ECOSYSTEMS AND HUMAN WELL BEING and human well... · 2008. 9. 11. · Achim Steiner, Director General, IUCN - The World Conservation Union Halldor Thorgeirsson, Coordinator, United

ECOSYSTEMSAND HUMANWELL-BEING

ECOSYSTEMSAND HUMANWELL-BEINGHealth Synthesis

M I L L E N N I U M E C O S Y S T E M A S S E S S M E N T

Millennium EcosystemAssessment Panel

Millennium Ecosystem Assessment BoardThe MA Board represents the users of the findings of the MA process.

Harold A. Mooney (co-chair), StanfordUniversity, United States of America

Angela Cropper (co-chair), TheCropper Foundation, Trinidad andTobago

Doris Capistrano, Center forInternational Forestry Research, Indonesia

Stephen R. Carpenter, University ofWisconsin-Madison, United States ofAmerica

Kanchan Chopra, Institute ofEconomic Growth, India

Partha Dasgupta, University ofCambridge, United Kingdom of GreatBritain and Northern Ireland

Rashid Hassan, University of Pretoria,South Africa

Rik Leemans, Wageningen University,the Netherlands

Robert M. May, University of Oxford,United Kingdom of Great Britain andNorthern Ireland

Prabhu Pingali, Food and AgricultureOrganization of the United Nations, Italy

Cristian Samper, Smithsonian NationalMuseum of Natural History, United Statesof America

Robert Scholes, Council for Scientificand Industrial Research, South Africa

Robert T. Watson, World Bank, UnitedStates of America (ex officio)

A. H. Zakri, United Nations University,Japan (ex officio)

Zhao Shidong, Chinese Academy ofSciences, China

Editorial Board ChairsJosé Sarukhán, Universidad NacionalAutÛnoma de MÈxico, Mexico

Anne Whyte, Mestor Associates Ltd.,Canada

MA DirectorWalter V. Reid, Millennium EcosystemAssessment, Malaysia and United States ofAmerica

Co-chairsRobert T. Watson, Chief Scientist,World Bank

A.H. Zakri, Director, Institute ofAdvanced Studies, United NationsUniversity

Institutional RepresentativesSalvatore Arico, ProgrammeOfficer, Division of Ecological andEarth Sciences, United NationsEducational, Scientific and CulturalOrganization

Peter Bridgewater, SecretaryGeneral, Ramsar Convention onWetlands

Hama Arba Diallo, ExecutiveSecretary, United NationsConvention to CombatDesertification

Adel El-Beltagy, DirectorGeneral, International Center forAgricultural Research in Dry Areas,Consultative Group onInternational Agricultural Research

Max Finlayson, Chair, Scientificand Technical Review Panel,Ramsar Convention on Wetlands

Colin Galbraith, Chair,Scientific Council, Convention onMigratory Species

Erika Harms, Senior ProgramOfficer for Biodiversity, UnitedNations Foundation

Robert Hepworth, ExecutiveSecretary, Convention on MigratorySpecies

Olav Kjørven, Director, Energyand Environment Group, UnitedNations Development Programme

Kerstin Leitner, AssistantDirector-General, SustainableDevelopment and HealthyEnvironments, World HealthOrganization

Alfred Oteng-Yeboah, Chair,Subsidiary Body on Scientific,Technical and Technological Advice,Convention on Biological Diversity

Christian Prip, Chair, SubsidiaryBody on Scientific, Technical andTechnological Advice, Conventionon Biological Diversity

Mario A. Ramos, BiodiversityProgram Manager, GlobalEnvironment Facility

Thomas Rosswall, ExecutiveDirector, International Council forScience - ICSU

Achim Steiner, Director General,IUCN - The World ConservationUnion

Halldor Thorgeirsson,Coordinator, United NationsFramework Convention on ClimateChange

Klaus Töpfer, Executive Director,United Nations EnvironmentProgramme

Jeff Tschirley, Chief,Environmental and NaturalResources Service, Research,Extension and Training Division,Food and Agriculture Organizationof the United Nations

Riccardo Valentini, Chair,Committee on Science andTechnology, United NationsConvention to CombatDesertification

Hamdallah Zedan, ExecutiveSecretary, Convention on BiologicalDiversity, United NationsConvention on Biological Diversity

At-large MembersFernando Almeida, ExecutivePresident, Business Council forSustainable Development-Brazil

Phoebe Barnard, Global InvasiveSpecies Programme, South Africa

Gordana Beltram, Undersecretary,Ministry of the Environment andSpatial Planning, Slovenia

Delmar Blasco, former SecretaryGeneral, Ramsar Convention onWetlands, Spain

Antony Burgmans, Chairman,Unilever N.V., the Netherlands

Esther Camac-Ramirez,Asociación Ixä Ca Vaá de Desarrolloe Información Indigena (AssociationIxacavaa for Indigenous Developmentand Information), Costa Rica

Angela Cropper President (ex offi-cio), The Cropper Foundation,Trinidad and Tobago

Partha Dasgupta, Professor,Faculty of Economics and Politics,University of Cambridge, UnitedKingdom of Great Britain andNorthern Ireland

José María Figueres, FundaciónCosta Rica para el DesarrolloSostenible, Costa Rica

Fred Fortier, Indigenous Peoples'Biodiversity Information Network,Canada

Mohamed H.A. Hassan,Executive Director, The Academy ofSciences for the Developing World,Italy

Jonathan Lash, President, WorldResources Institute, United States ofAmerica

Wangari Maathai, AssistantMinister for Environment andNatural Resources, Kenya

Paul Maro, Professor, Departmentof Geography, University of Dar esSalaam, Tanzania

Harold A. Mooney (ex officio),Professor, Department of BiologicalSciences, Stanford University,United States of America

Marina Motovilova, Faculty ofGeography, Laboratory of MoscowRegion, Russian Federation

M.K. Prasad, Environment Centreof the Kerala Sastra Sahitya Parishad,India

Walter V. Reid, Director,Millennium Ecosystem Assessment,Malaysia and United States ofAmerica

Henry Schacht, past Chairman ofthe Board, Lucent Technologies,United States of America

Peter Johan Schei, Director, TheFridtjof Nansen Institute, Norway

Ismail Serageldin, Director,Bibliotheca Alexandrina, Egypt

David Suzuki, Chair, DavidSuzuki Foundation, Canada

M.S. Swaminathan, Chairman,MS Swaminathan ResearchFoundation, India

José Galízia Tundisi, President,International Institute of Ecology,Brazil

Axel Wenblad, Vice President ofEnvironmental Affairs, Skanska AB,Sweden

Xu Guanhua, Minister, Ministry ofScience and Technology, China

Muhammad Yunus, ManagingDirector, Grameen Bank,Bangladesh

A Report of the Millennium Ecosystem Assessment

Core Writing Team Carlos Corvalan, Simon Hales, Anthony McMichael

Extended Writing Team Colin Butler, Diarmid Campbell-Lendrum, Ulisses Confalonieri, Kerstin Leitner, Nancy Lewis, Jonathan Patz,Karen Polson, Joel Scheraga, Alistair Woodward, Maged Younes and many MA authors.

Review EditorsJosé Sarukhán and Anne Whyte (co-chairs); Philip Weinstein and other members of the MA Board of ReviewEditors.

ECOSYSTEMSAND HUMANWELL-BEING

Health Synthesis

Printed in France.

WHO Library Cataloguing-in-Publication Data

Ecosystems and human well-being : health synthesis : a report of the Millennium Ecosystem Assessment / Core writing team: Carlos Corvalan,Simon Hales, Anthony McMichael ; extended writing team: Colin Butler ... [et al.] ; review editors: José Sarukhán ... [et al.].

1. Ecosystem 2. Environmental health 3. Health status 4. Development 5. Goals 6. Risk assessment I. Corvalán, Carlos F. II. Hales, Simon.III. McMichael, Anthony J. IV. Butler, Colin. V. Sarukhán, José.

ISBN 92 4 156309 5 (NLM classification: WA 30)

© World Health Organization 2005All rights reserved. Publications of the World Health Organization can be obtained from WHO Press, World Health Organization, 20 Avenue Appia,1211 Geneva 27, Switzerland (tel: +41 22 791 2476; fax: +41 22 791 4857; email: [email protected]). Requests for permission to reproduce ortranslate WHO publications – whether for sale or for noncommercial distribution – should be addressed to WHO Press, at the above address (fax: +41 22 791 4806; email: [email protected]).

The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on thepart of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning thedelimitation of its frontiers or boundaries. Dotted lines on maps represent approximate border lines for which there may not yet be full agreement.

The mention of specific companies or of certain manufacturers’ products does not imply that they are endorsed or recommended by the WorldHealth Organization in preference to others of a similar nature that are not mentioned. Errors and omissions excepted, the names of proprietaryproducts are distinguished by initial capital letters.

All reasonable precautions have been taken by the World Health Organization to verify the information contained in this publication. However, thepublished material is being distributed without warranty of any kind, either express or implied. The responsibility for the interpretation and use ofthe material lies with the reader. In no event shall the World Health Organization be liable for damages arising from its use.

The named authors alone are responsible for the views expressed in this publication.

Foreword ii

Reader’s Guide iv

Summary for Decision-Makers 1

Key Health Questions in the Millennium Ecosystem Assessment 111 Why do ecosystems matter to human health? 12

1.1 Introduction 121.2 Current state of ecosystems and associated human health status 12

2 How have ecosystems changed and what are the health implications? 27

3 How might ecosystems change and what would be the health implications? 303.1 Critical drivers and other factors affecting future changes to health 343.2 Plausible future changes in ecosystems and the health effects in different

sectors and regions 353.3 Possible thresholds, regime shifts or irreversible changes 36

4 What actions are required to address the health consequences of ecosystem change? 384.1 Reducing vulnerability 384.2 The Millennium Development Goals 39

5 How can priorities be established for actions to address the health consequences of ecosystem change? 425.1 What considerations are important when setting priorities and what is science's

role in informing decisions? 425.2 How can we measure the size and distribution of the health effects of

ecosystem change? 425.3 What kinds of intervention options are available? 435.4 How should priorities for these options be established? 455.5 How can stakeholders and policy-makers be involved? 455.6 How does uncertainty affect priority-setting? 46

6 What are the policy implications of the most robust findings and key uncertainties? 486.1 Policy implications of the most robust findings 486.2 Policy implications of key uncertainties 49

Appendix A. Abbreviations, Acronyms and Figure Sources 51Appendix B. Assessment Report Tables of Contents 52

CONTENTS

Ecosystems and Human Well-being: Hea l th Synthes is i

FOREWORD

It is becoming increasingly clear that population growth and economic development are leading to rapid changes in ourglobal ecosystems. In recognition of this, the United Nations’ Secretary-General Kofi Annan, in a 2000 report to theGeneral Assembly entitled: "We the Peoples: The Role of the United Nations in the 21st Century," called for the MillenniumEcosystem Assessment to be undertaken. Since 2001, the Millennium Ecosystem Assessment has worked to assess theconsequences of ecosystem change for human well-being, and establish the scientific basis for actions needed to enhancethe conservation and sustainable use of those systems, so that they can continue to supply the services that underpin allaspects of human life.

The assessment exercise has involved more than 1 300 experts worldwide. The findings provide the strongest evidence sofar of the impact of our actions on the natural world. They show, for example, that over the past 50 years, humans havechanged natural ecosystems more rapidly and extensively than in any comparable period in human history. Thistransformation of the planet has contributed to substantial net gains in human well-being and economic development.But not all regions and groups of people have benefited from this process, and many have been harmed. Moreover, thefull costs associated with these gains are only now becoming apparent. Approximately 60% of the ecosystem "services"examined, from regulation of air quality to purification of water, are being degraded or used unsustainably.

Nature's goods and services are the ultimate foundations of life and health, even though in modern societies thisfundamental dependency may be indirect, displaced in space and time, and therefore poorly recognized. These moredistant and complex links mean that we now need to look at environmental health through a broader lens. Health risksare no longer merely a result of localized exposures to "traditional" forms of pollution – although these still certainlyexist. They are also a result of broader pressures on ecosystems, from depletion and degradation of freshwater resources,to the impacts of global climate change on natural disasters and agricultural production. Like more traditional risks, theharmful effects of the degradation of ecosystem services are being borne disproportionately by the poor. However,unlike these more traditional hazards, the potential for unpleasant surprises, such as emergence and spread of newinfectious diseases, is much greater.

This report represents a call to the health sector, not only to cure the diseases that result from environmentaldegradation, but also to ensure that the benefits that the natural environment provides to human health and well-beingare preserved for future generations.

LEE Jong-wookDirector-GeneralWorld Health Organization

This report synthesizes the findings from the Millennium Ecosystem Assessment's (MA) global and sub-globalassessments of how ecosystem changes do, or could, affect human health and well-being. All the MA authors and revieweditors have contributed to this report through their contributions to the underlying assessment chapters on which thistext is based.

Five additional MA synthesis reports were prepared to facilitate access to information by other audiences: generaloverview; UNCCD (desertification); CBD (biological diversity); Ramsar Convention (wetlands); and business. EachMA sub-global assessment also will produce additional reports to meet the needs of its own audience. The full technicalassessment reports of the four MA working groups will be published in mid-2005 by Island Press.

All of the assessment's printed materials, together with core data and a glossary of terminology used in the technicalreports, will be available on the Internet at www.maweb.org. Appendix A lists the acronyms and abbreviations used inthis report. References for the underlying chapters in the full technical assessment reports of each working group appearin parentheses in the body of this synthesis report. A list of the assessment report chapters is provided in Appendix B.

The following set of words has been used, where appropriate, to indicate estimated levels of certainty about theobservations or conclusions: very certain (98% or greater probability), high certainty (85-98% probability), mediumcertainty (65-85% probability), low certainty (52-65% probability) and very uncertain (50-52% probability). Theseestimates are based on the collective judgment of the authors, using the observational evidence, modelling results andrelevant theory. Elsewhere the following qualitative scale is used to gauge the level of scientific understanding: well-established, established but incomplete, competing explanations and speculative. These terms appear in italics.

Throughout this report, dollars ($) indicate U.S. dollars, and tonne means metric tonne. The term billion is used inaccordance with the WHO definition – of one thousand millions.

iv Ecosystems and Human Well-being: Hea l th Synthes is

READER’S GUIDE

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Why do ecosystems matter to human health?

cosystems are the planet's life-support systems -for the human species and all other forms of life.

Human biology has a fundamental need for food, water,

clean air, shelter and relative climatic constancy. Otherhealth benefits include those derived from having a fullcomplement of species, intact watersheds, climateregulation and genetic diversity. Stresses on freshwatersources, food-producing systems and climate regulationcould cause major adverse health impacts (high certainty)(see Figure SDM1).

Ecosystems and Human Well-being: Hea l th Synthes is 1

SUMMARY FOR

DECISION-MAKERS

Figure SDM1. Harmful effects of ecosystem change on human health

This figure describes the causal pathway from escalating human pressures on the environment through to ecosystem changes resulting in diversehealth consequences. Not all ecosystem changes are included. Some changes can have positive effects (e.g. food production).

The health impacts of ecosystem change are global as well as local; here dust from north Africa is distributed widelyacross the continent, with potential impacts on health.Degradation of drylands, as well as biomass burning,exacerbates problems associated with dust storms.

SeaWiFS / NASA / Goddard Space Flight Center and ORBIMAGE/ http://visibleearth.nasa.gov

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Ecosystem services are indispensable to the well-beingand health of people everywhere. In addition to providinglife's basic (above-mentioned) needs, changes in their flowaffect livelihoods, income, local migration and, on occasion,political conflict. The resultant impacts on economic andphysical security, freedom, choice and social relations havewide-ranging impacts on well-being and health.

The causal links between environmental change andhuman health are complex because often they areindirect, displaced in space and time, and dependent ona number of modifying forces. For example, climatechanges can place stresses on agricultural production or theintegrity of coral reefs and coastal fisheries. This can lead tomalnutrition, stunted childhood growth, susceptibility toinfectious diseases and other ailments. Deforestation mayalter infectious disease patterns, for example by affectingvector (e.g. mosquito) distributions over time. The MAidentified key ecosystem services and their links to humanhealth. These are described in more detail below.

Ecosystem services and human health Fresh water

Many aspects of the world's hydrological (water) cycle areregulated by the natural functions of ecosystems andassociated geophysical processes (such as evaporation and thefunctioning of the climate system). Human interventions inwatersheds, lakes and river systems take many forms -deforestation, farming, irrigation, river damming andextractions from subterranean aquifers. Wetlands play acrucial role in the filtering of fresh water, including theremoval of various chemicals and potentially toxic elements(e.g. heavy metals such as cadmium and lead).

Fresh water is essential for human health. It is used forgrowing food, drinking, personal hygiene, washing,cooking and the dilution and recycling of wastes. Waterscarcity jeopardizes food production, human health,economic development and geopolitical stability. Globally,the availability of water per person has declined markedlyin recent decades. One third of the world's populationnow lives in countries experiencing moderate to highwater stress. This fraction will continue to increase as bothpopulation size and per capita water demand grow -reflecting the escalating use of fresh water for irrigatedagriculture, livestock production, industry and therequirements of wealthier urban residents.Over 1 billion people lack access to safe water supplies;2.6 billion people lack adequate sanitation. This has led towidespread microbial contamination of drinking water.Water-associated infectious diseases claim up to 3.2million lives each year, approximately 6% of all deathsglobally. The burden of disease from inadequate water,sanitation and hygiene totals 1.7 million deaths and theloss of more than 54 million healthy life years.Investments in safe drinking-water and improvedsanitation show a close correspondence withimprovements in human health and economicproductivity. Every day each person needs 20-50 litres ofwater free from harmful chemical and microbialcontaminants, for drinking, cooking and hygiene. Thegrowing challenge of providing this basic service to largesegments of the human population is highlighted by oneof the United Nations Millennium Development Goals,MDG-7, which calls for halving by 2015 the proportionof people without sustainable access to safe drinking-waterand basic sanitation.

FoodProductive terrestrial and marine ecosystems, both wild andmanaged, are the source of our food - a prerequisite forhealth and life. Global aggregate food production currentlyis sufficient to meet the needs of all. However, of the presentworld population of 6.5 billion, over 800 million - nearly allof them in low-income countries - do not obtain enoughprotein and calories for energy. Worldwide, a similar(increasing) number are now overfed. Several billion peopleexperience deficiences of one or more micronutrients(especially vitamin A, zinc and iodine).

In poor countries, especially in rural areas, the health ofhuman communities often is directly dependent on locallyproductive ecosystems providing sources of basicnutrition. Local food production is critical in preventing

2 Ecosystems and Human Well-being: Hea l th Synthes is

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Anopheles stephensi mosquito, a known malaria vector, with a distribution fromEgypt to China, obtaining a blood meal from a human host. In the wild, mosquitolarvae are found in sites such as stream pools and margins, puddles, irrigationchannels and springs. In urban areas the larvae are found in a wide variety ofartificial containers including cisterns, wells, tubs and fountains.


hunger and promoting ruraldevelopment in areas where the poordo not have the capacity to purchasefood from elsewhere. Wild foods areimportant locally in many developingcountries, often bridging the hungergap created by stresses such asdroughts and civil unrest. In richerurban communities, humandependence on ecosystems for food isless apparent but no less fundamental.

Worldwide, undernutrition accounts fornearly 10% of the global burden ofdisease. Almost all of this occurs in poorcountries where food production has notkept up with population increases,particularly in sub-Saharan Africa.Furthermore, undernutrition is relatedstrongly to poverty in developingcountries with high mortality rates; between one-sixth andone-quarter of the burden of disease is related to childhoodand maternal undernutrition. In developed countries withlow mortality rates, diet-related risks (mainly overnutrition,often in combination with physical inactivity) account forbetween one-tenth and one-third of the burden of disease.The nutritional disparity between rich and poor primarily iscaused by social and economic factors as well as the unevenimpacts of world food trade. In the future, however, adversechanges in food-producing ecosystems are likely to play anincreasingly important role in nutritional disparities(medium certainty).

Timber, fibre and fuel Many processes and resources in nature provide power thatcan be harnessed by human communities, especially wind,water and biomass combustion. Different geographicalregions and countries at varying stages of development usevaried methods of generating power. This has many healthimpacts and the availability of power, especially electricity,has important applications in health care.

Over half of the world’s population continues to rely uponsolid fuels for cooking and heating. These fuels - includingwood, crop stubble and animal dung - are a direct productof ecosystems. Indoor air pollution produced by thecombustion of biomass fuels as well as coal in poorlyventilated heating and cooking environments, causessignificant mortality and morbidity from respiratorydiseases, particularly among children.

In areas where the demand for wood has surpassed localsupply and people cannot afford other forms of power,there is increased vulnerability to illness and malnutritionfrom consuming (unboiled) microbiologicallycontaminated water and improperly cooked food, as well asfrom exposure to cold. Poor women and children in ruralcommunities often are those most affected by a scarcity offuel wood. Many must walk long distances searching forfuel and firewood (as well as water) and hauling it home.These time-consuming tasks reduce the time and energyavailable for tending crops, cooking meals or attendingschool. Therefore, provision of adequate and sustainableenergy supplies is fundamental not only to economicdevelopment, but also to health and well-being.

Outdoor air pollution is caused predominantly by thecombustion of non-renewable fossil fuels for electricitygeneration, transport and industry. Globally, urban airpollution is responsible for significant mortality everyyear, mostly as a result of heart and lung diseases. Inaddition, the accompanying release of a major greenhousegas (CO2) and its consequent contribution to globalwarming have further, mostly adverse, impacts on humanhealth. Air pollution due to forest fires and burningpractices in agriculture also can have serious local andregional health consequences. This was highlighted by thepublic health experiences in south-east Asia in 1998,following widespread (drought-associated) forest fires inSumatra and Kalimantan, Indonesia in the latter part of1997 and early 1998.

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Cooking and heating using solid fuels in poorly verticlated houses results in very high levels of exposure to indoor airpollution, especially among women and children. WHO estimates that this causes over 1.6 million deaths per year.

Timber exploitation has contributed to species' loss andecosystem degradation in many regions of the developingworld, affecting traditional livelihoods, microbial ecologyand causing other health-related risks. In particular thedestruction and fragmentation of habitats, accompaniedby new patterns of human-microbe contacts, hasintroduced new infectious diseases into humanpopulations – e.g. the Nipah virus in Malaysia andvarious viral haemorrhagic fevers in South America.Deforestation also endangers health by intensifying theeffects of natural disasters such as floods and landslides(see Box 1.1).

Biological productsMillions of people around the world depend partly orfully on natural products collected from ecosystems formedicinal purposes. Although synthetic medicines (overhalf of which originated from natural precursors) areavailable for many purposes, the global need and demandfor natural products persists. Some of the better-knownmainstream pharmaceuticals from natural sources includeaspirin, digitalis and quinine.

Nutrient and waste management, processing anddetoxificationEcosystems play a critical role in the recycling andredistribution of nutrients. This fundamental serviceunderpins the health of plant and animal species everywhere. Disruption of nutrient cycling can impair soil fertility,

resulting in reduced crop yields. This impairs thenutritional status of households (medium certainty) anddiet deficiencies (both macro-and micro-nutrients) harmchildren's physical and mental development. In turn, thiscan impair the livelihoods of farmers and limit theoptions open to their children.

Human health can be harmed by exposure to certain toxinsproduced by algal blooms. These can occur as a result ofeutrophication of waterways excessively loaded with nitratesand phosphates infiltrating from run-off water discharged inagricultural, industrial and domestic processes.

Humans are also at risk from inorganic chemicals andpersistent organic chemical pollutants in food and water.Such exposures can occur when attempts to improvewater access lead to contamination from natural sources(as occurred recently with arsenic contamination of tubewells in Bangladesh), and when human actions releasetoxic chemicals into the environment (for example,through pesticide use). Toxic chemicals in water and foodcan have adverse effects on various organ systems.Exposure to low concentrations of some chemicals (suchas PCBs, dioxins and DDT) may cause endocrinedisruption, interfering with normal human hormone-mediated physiology and impairing reproduction.

Regulation of infectious disease Infectious diseases are caused by viruses, bacteria and othertypes of microbes or parasites. Only a few infectious agentscause actual disease in plants, animals and humans; usuallythese are constrained geographically and seasonally byecosystems and ecological relationships in nature. Patterns ofmicrobe entry into the human species (sometimes as newmutants) are sensitive to climatic and micro-environmentalconditions. These factors may impact upon the spread ofmicrobes between humans; their more distantdissemination; and the activity of vector organisms (e.g.mosquitoes) involved in their transmission. Often human-induced changes in ecosystems and in physicalenvironmental conditions alter these natural influences oninfectious agent range and activity.

The pattern and extent of change in incidence of aparticular infectious disease depends on the particularecosystems affected, type of land-use change, disease-specifictransmission dynamics, sociocultural changes and thesusceptibility of human populations. Infectious disease risksare affected particularly by destruction of, or encroachmentinto, wildlife habitat (particularly through logging and road


Bark of whitewillow (Salix alba)was recommendedas a pain reliever bythe Ancient Greekphysician,Hippocrates. Salicin, the activeingredient in willowbark – similarlyfound in the spireaor meadowsweetplant (Filipendulaulmaria/Spiraeaulmaria) – wasdiscovered in theearly 1800s.Aspirin® wasintroduced to thepublic in 1899,following synthesisof the salicinderivative:acetylsalicylic acid.

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building); changes in the distribution and availabilityof surface waters, e.g. through dam construction,irrigation and stream diversion; agricultural land-usechanges, including proliferation of both livestock andcrops; uncontrolled urbanization or urban sprawl;resistance to pesticide chemicals used to controlcertain disease vectors; climate variability and change;migration and international travel and trade; and theaccidental or intentional human introduction ofpathogens.

Recently, there has been an upturn in the rate ofemergence or re-emergence of infectious diseases. Factors contributing substantially to this trendinclude: intensified human encroachment on naturalenvironments; reductions in biodiversity (includingnatural predators of vector organisms); particularlivestock and poultry production methods; andincreased long-distance trade in wild animal species(including as food). Further contributors include: habitatalterations that lead to changes in the number of vectorbreeding sites or in reservoir host distribution; nicheinvasions or interspecies host transfers; human-inducedgenetic changes of disease vectors or pathogens (such asmosquito resistance to pesticides or emergence ofantibiotic-resistant bacteria); and environmentalcontamination by infectious disease agents.

Cultural, spiritual and recreational services People and communities obtain many non-materialbenefits from ecosystems. Ecosystems provide sites andopportunities for tourism, recreation, aestheticappreciation, inspiration and education. Such services canimprove mental health; enhance a subjective sense ofculture or place; and also enrich objective knowledge ofnatural and social sciences, e.g. botany, biology, historyand archaeology. Health benefits of these services may bematerially less tangible than those captured byconventional health indicators or standard economicvaluation measures. Nonetheless, such services are highlyvalued by people in all societies. Various traditionalpractices linked to ecosystem services, including seasonalcycles of thanks and celebration, play an important role indeveloping social capital and enhancing social well-being.

Climate regulationRegional climatic conditions are influenced by changes inecosystems and landscapes, especially deforestation anddesertification. On a larger scale, the ongoing human-

induced alteration of atmospheric composition (thegreenhouse effect) also affects climatic conditions.

Each of the ecosystem services described above is sensitiveto climatic conditions and therefore will be affected byhuman-induced climate change. In turn, these ecosystemchanges will affect the well-being and health of humanpopulations. Meanwhile, climate change itself does, andwill, affect human health.

Although climate change will have some beneficial effectson human health, most are expected to be negative.Direct effects, such as increased mortality from heatwaves,are most readily predicted but indirect effects are likely tohave greater overall impact. Human health is likely to beaffected indirectly by climate-induced changes in thedistribution of productive ecosystems and in theavailability of food, water and energy supplies. Thesechanges will affect the distribution of infectious diseases,nutritional status and patterns of human settlement.

Extreme weather events (including heatwaves, floods, stormsand droughts) and sea-level rise are anticipated to increase asa result of climate change. These events have local andsometimes regional effects: directly through deaths andinjuries and indirectly through economic disruption,infrastructure damage and population displacement. In turn,this may lead to increased incidence of certaincommunicable diseases as a result of overcrowding; lack ofclean water and shelter; poor nutritional status; and adverseimpacts on mental health.

Human health is likely to be affected indirectly by climate-induced changes in the distributionof productive ecosystems. This photo shows rice cultivation in south-east Asia.

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Globally, the annual absolute number of people killed,injured or made homeless by natural disasters isincreasing. An important factor is the growth in humansettlements in geographically sensitive locations, such ascoastal zones and flood plains, exposed to extremeevents. Case-studies have shown that environmentaldegradation has reduced the capacity of ecosystems toact as a buffer against climate extremes. For example,degraded coral reefs and mangrove forests may lose theircapacity to stabilize coastlines and protect against someof the damaging effects of storm surges. Heavy rainfalling on deforested slopes may be more likely totrigger landslides. In many cases, the only landsavailable to poor households and communities forsettlement may also be highly vulnerable to impactsfrom weather extremes, e.g. flooding, as well as tonatural disasters.

How have ecosystems changed andwhat are the health implications?

As a result of human actions, the structure andfunctioning of the world's ecosystems changed morerapidly in the second half of the twentieth centurythan at any other time in human history. Themagnitude of these changes is growing as both populationsize and intensity of economic activity increase. Oneconsequence is that the diversity of life on Earth is beingdepleted at an accelerating rate. The loss of plant andanimal species is irreversible. So, too, is the unravelling orelimination of whole ecosystems.

Human societies also achieve benefits for well-beingand health by restructuring and managing variousecosystems. In most countries and regions, the changesmade to food-producing ecosystems in recent decadeshave provided substantial gains in production. Many ofthe most significant human-induced changes toecosystems have been essential to meet growing needs forfood and water. These changes have helped to reduce theproportion of malnourished people and improve humanhealth.

However, these gains have been achieved at increasingcost: degradation of 60% of ecosystem services;exacerbation of poverty for some; and growinginequities and disparities across groups of people. Theintensification of food production methods, expanded useof irrigation, forest-clearing and the intensive exploitationof capture fisheries (e.g. fishing in open marine or inlandwaters), all have entailed losses in natural resources andchanges in ecosystems' functions. The loss from nature ofpotential medicinal compounds is one consequence.Further, these changes to ecosystems have occurredunevenly, often exacerbating the inequalities in access toecosystem services and contributing further to poverty.Both within and between countries, poverty is aconsistent underlying determinant of undernutrition; lackof access to safe water and sanitation; and lack of access toother public services important to health and well-being,e.g. health services, garbage disposal, etc. These adversefactors have staggering human health implications, costingmillions of lives each year.


Extreme weather events, including heatwaves, floods, storms and droughts, areanticipated to increase as a result of climate change. This is a true colour imageof Hurricane Frances as it passed over the Bahamas with sustained winds of 185kph, 3 September 2004.

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By dint of much higher per-person consumptionlevels, the world's richer populations exertdisproportionate pressure on global ecosystems - yetare less vulnerable to the adverse consequences.These populations exhibit less vulnerability to theeffects of ecosystem degradation, largely as a result oftheir ability to import resources from, and displacehealth risks to, other geographical locations.

Poverty and hunger have tended to force rural peopleonto marginal drought-prone lands with poor soilfertility, and others to urban slums. About 1 billion peopleare affected by land degradation such as that caused by soilerosion, waterlogging or salinity of irrigated land. Erosion hascaused substantially reduced crop yields in Africa.

Diminished human health and well-being tends toincrease the immediate dependence on ecosystemservices. The resultant additional pressure can (further)damage the ecosystems' capacity to deliver services(medium certainty). As well-being declines, people'soptions for regulating their use of natural resources atsustainable levels are reduced. Immediate needs inevitablytake priority, increasing the pressure on ecosystem services,and can create a downward spiral of increasing poverty andfurther degradation of ecosystem services.

How might ecosystems change andwhat would be the healthimplications?

Continuation of the dual trends of growing exploitationof ecosystem services and the generally decliningcondition of most ecosystems is unsustainable and likelyto lead to irreversible changes. When changes to anecosystem cross a threshold, recovery is generally slow andcostly, even impossible. Thresholds may become lower asanthropogenic impacts simplify these natural systems andreduce their intrinsic resilience to change.

Many of the people and places affected adversely byecosystem changes and declining ecosystem servicesare highly vulnerable and ill-equipped to cope withfurther loss of ecosystem services. Highly vulnerablegroups include those whose needs for ecosystem servicesalready exceed supply. This includes people who lackadequate safe water supplies as well as those living in areas

with declining agricultural yields and therefore at risk ofmalnutrition and impaired child development. In tropicaland semitropical regions much of the ongoingdeforestation alters the dynamics of infectious diseasetransmission, especially by changing the conditions formosquito, tick and rodent populations. This may increaseoutbreaks of diseases such as malaria and dengue fever.

The regions facing the greatest challenges in achievingthe MDGs overlap largely with those facing thegreatest problems related to the sustainable supply ofecosystem services. Many of these regions include largeareas of drylands, in which the combination of populationgrowth and land degradation is increasing humanvulnerability to both economic and environmental changeand, consequently, impairing well-being and health.

Ecosystem changes may occur on such a large scale asto have a catastrophic effect on human health. Thereis an increasing risk of non-linear changes in ecosystems,including accelerating, abrupt and potentially irreversiblechanges (established but incomplete evidence). Theincreased likelihood of these non-linear changes stemsfrom the loss of biodiversity and growing pressures frommultiple direct drivers of ecosystem change. Similar non-linearities are anticipated in social-economic-politicalcontexts. For example, widespread food insecurityresulting from severe climate change, institutional failureand increasingly damaged soils could worsen inequalityand lead to widespread conflict. Meanwhile, a great manyindividually less dramatic losses in ecosystem services arelikely to influence human health adversely.

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The MA Scenarios Working Group developed four scenariosto explore possible future trends and developments until2050, and the consequences for ecosystem services andhuman well-being. Scenarios are plausible, proactive andrelevant stories about how the future might unfold. They arenot forecasts, projections, predictions or recommendations.Rather, they are implications of specific policy outcomesbased on current knowledge of underlying socioecologicalprocesses. The MA scenarios are used to explore a range ofcontexts under which sustainable development could bepursued, and approaches supporting sustainable development.The scenarios are: (i) Global Orchestration: globally-driveneconomic development emphasising social responsibility,equity, and social public goods, and with a reactive approachto ecosystems; (ii) Order from Strength: regionalizeddevelopment with an emphasis on security and economicgrowth and a reactive approach to ecosystems; (iii) AdaptingMosaic: regionalized development emphasising proactivemanagement of ecosystems, local adaptation and flexiblegovernance; and (iv) TechnoGarden: globalized developmentusing technology to achieve environmental outcomes, with aproactive approach to ecosystems (see Box 3.2).

Under all four MA scenarios, the projected changes inthe underlying driving forces result in significantgrowth in consumption of ecosystem services,continued loss of biodiversity and further degradationof some ecosystem services.

• During the next 50 years, demand for food is projectedto grow by 70-80% and demand for water by 30-85%.Water withdrawals in developing countries areprojected to increase significantly.

• Food security is not achieved under any of the MAscenarios by 2050. Child malnutrition will be difficultto eliminate, despite an increasing food supply andmore diversified diets.

• A severe deterioration of the services provided byfreshwater resources (such as aquatic habitat; fishproduction; water for households, industry andagriculture) is found in the scenarios that are reactiveto environmental problems. Less severe but stillimportant declines are expected in the scenarios thatare more proactive about environmental problems.

• Habitat loss and other ecosystem changes are projectedto lead to a decline in local diversity of native speciesby 2050.

In the scenarios with more promising health prospects,the number of undernourished children is reduced andthe burden of epidemic diseases such as malaria andtuberculosis also falls. Improved vaccine development anddistribution could allow populations to cope relatively wellwith the next influenza pandemic, while the impact of othernew infectious diseases should also be limited if well-coordinated public health measures are in place. Under a lessoptimistic scenario, the number of malnourished childrenincreases. The health and social conditions for rich and poorcountries diverge and a negative spiral of poverty, declininghealth and degraded ecosystems could develop.

What actions would address thehealth consequences of ecosystemchange?

There are two strategies for avoiding disease and injurycaused by ecosystem disruption. One - preferable inprinciple - is to prevent, limit or manage the environmentaldamage. The other is to make adaptive changes that willprotect individuals and populations from the adverseconsequences of ecosystem change. These should not beviewed as alternatives; both strategies are useful.Two aspects need to be considered to understand thepotential negative health impacts of ecosystem change: thecurrent (and likely future) intrinsic vulnerability (e.g.nutritional status) of populations and their likely futurecapacity for adaptation. These are closely related. In manycases the forces that place populations at risk (such aspoverty and high burdens of disease) also impair theircapacity to prepare for the future.


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As part of a strategy for achieving the MDGs,improved ecosystem management would need toaddress a complex set of underlying causes ofenvironmental change. This entails cross-sectoralpolicies, institutions and investments on local,national, regional and global scales. Achievement ofthe MDGs, enhanced human well-being and improvedhuman health status requires particular attention toimproving ecosystem management and the capacity forpolicy-making at national and local levels. Meanwhile,there is the need to address global challenges includinglong-term climate change, the depletion of internationalfisheries and the spread of exotic species.

How can priorities be established foractions to address the healthconsequences of ecosystem change?

There is a need for a more systematic inventory, byregion and country, of current and likely populationhealth impacts of ecosystem change. Clearly, informationis a crucial resource. An appropriate metric - for instancedisability-adjusted life years (DALYs) gained or lost - shouldbe used to make at least approximate estimates of theseimpacts. This will require an unusual level of inter-disciplinary analysis and synthesis in which the populationhealth sciences are central, especially epidemiology. Burden-of-disease evaluations within the context of ecosystemchange are appropriate for aggregating health impactsthrough a range of mechanisms and, potentially, can aidpriority-setting and decision-making to address ecosystem change. However, they must be considered as only onecomponent of evidence; they cannot account fully forcomplex causal pathways, long timescales and potentialirreversibility. These important properties need to beincluded in the final considerations about any response toecological change.

Priority-setting of actions to address the healthconsequences of ecosystem change also should reflectthe priorities and values of all those affected by theproposed actions. Therefore the final decisions aboutpriorities should be taken either by individuals or by theirlegitimate political representatives, with reference to theprevailing stakeholder/community values.

It is important to consider which sections of thepopulation are most affected by ecological changes,including the distribution of disease impacts by age,gender, social status, ethnicity and geographical region.Global estimates for the year 2000 indicated that in poorcountries with high mortality rates, between one-sixth andone-quarter of the total disease burden was attributable tochildhood and maternal undernutrition. Children andpregnant women are at much greater risk for morbidity andmortality from malaria, particularly if malnourished;morbidity and mortality due to heatwaves is highest amongthe elderly. Many other such differences in vulnerability todisease have been documented. For example, in many poorcountries the risk of child diarrhoeal disease is relatedstrongly to poverty and the risk of malnutrition among thepoor is greater among girls than among boys.

The responses to ecosystem changes include mitigationand adaptation. Mitigation implies reducing or reversingthe change process. Adaptation aims to increase theresilience of both social systems and ecosystems to theimpacts of ecosystem change in order to reduce thecurrent and future health risks – and to take advantage ofbeneficial consequences of ecosystem changes. Decisionson priority actions should consider the best evidenceavailable on the likely effectiveness of any intervention ineither class. Mitigation and adaptation response options canbe legal, economic, financial, institutional, social,behavioural, technological or cognitive. They encompassspontaneous responses to ecosystem change and planned(anticipatory) interventions by affected individuals andinstitutions such as governments. In order to protect humanhealth, responses very often must involve actions outside ofthe health sector – particularly in agriculture, industry,education, coastal zone management and urban planning.

Monitoring nutritional status in Zambia: an officer from the Central StatisticalOffice collects data on food and water availability and prices of important fooditems in a village.

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What are the policy implications ofecosystem change's threats to health?

Measures to ensure ecological sustainability wouldsafeguard ecosystem services and thereby benefit healthin the long term. A good and equitable health status withina population confers a range of social, economic andpolitical benefits. Society is more cohesive, more productiveand more stable. For a population weighed down by diseaserelated to poverty and by inequities in access to food andother resources, equitable provision of these resources wouldhave major health benefits (high certainty). Where ill-healthis caused, directly or indirectly, by excessive consumption ofecosystem services (such as food and energy), substantialreductions in consumption would have major healthbenefits and simultaneously reduce pressure on life-supportsystems (high certainty).

Increasing populations and growing economies result inhigher total consumption. In addition to the pressure onecosystems this situation directly increases certain healthrisks - such as those from over-nutrition and physicalinactivity. A reduction in consumption of animal productsand refined carbohydrates (simple sugars) in rich countrieswould have benefits for both human health and ecosystems.The rise of obesity in urban populations around the world isessentially a 'human ecological' problem due to the societal-level imbalance between energy ingested and energyexpended - it is a modern way-of-living problem. Theimplementation of better transport practices and systemscould lead to fewer injuries, decreases in obesity andcardiovascular disease through more physical activity insedentary populations, and reductions in local air pollutionand greenhouse gas emissions.

Integration of national agricultural and food security policieswith the economic, social and environmental goals ofsustainable development could be achieved, in part, byensuring that the environmental and social costs ofproduction and consumption are reflected more fully in themarket price of food and water.

Cross-sectoral policies that promote ecologicallysustainable development and address underlying drivingforces also will be essential. Agenda 21, the internationalaction plan adopted in 1992 at the United NationsConference on Environment and Development (EarthSummit), and the World Summit on SustainableDevelopment Plan of Implementation, adopted in

Johannesburg in 2002, both describe a comprehensiveapproach to ecologically sustainable developmentincorporating cross-sectoral policies. Within these twoframeworks, the following strategies have specific relevanceto health.

• Mitigation strategies that reduce the underlying causes ofecosystem change, while simultaneously improvinghuman health.

• Adaptation strategies to reduce the effect of ecosystemdisruption on health (addressing direct, mediated andlong-term health impacts).

• Integrated action for health, such as a health impactassessment of major development projects, policies andprogrammes and indicators for health and sustainabledevelopment.

• Inclusion of health in sustainable development planningefforts such as Agenda 21, in multilateral trade andenvironmental agreements and poverty reductionstrategies.

• Improvement of intersectoral collaboration betweendifferent tiers of government, government departmentsand NGOs.

• International capacity-building initiatives that assesshealth and environment linkages, using the knowledgegained to create more effective national and regionalpolicy responses to environmental threats.

• Dissemination of knowledge and good practice on healthgains from intersectoral policy.

The ongoing degradation of ecosystem services is asignificant barrier to achieving the MDGs. Ecologicallyunsustainable use of ecosystem services raises the potentialfor serious and irreversible ecological change. This mayoccur on such a large scale as to have a catastrophic effecton the economic, social and political processes on whichsocial stability, human well-being and good healthdepend. The MDGs give prominence to achievingreductions in malnutrition, infectious diseases, maternalmortality, exposure to unsafe drinking-water and, mostimportantly, poverty. All these goals are seriouslyjeopardized by continuing decline in the world'secosystems.

This indicates strongly that a precautionary approach toenvironmental protection is the most effective way toprotect and enhance health. Unavoidable uncertaintiesabout aspects of the risks to well-being and health fromenvironmental changes should not be an excuse for delayingpolicy decisions.


1. Why do ecosystems matter to human health? 12

2. How have ecosystems changed and what are the health implications? 27

3. How might ecosystems change and what would be the health 30implications?

4. What actions are required to address the health consequences of 38ecosystem change?

5. How can priorities be established for actions to address the health 42consequences of ecosystem change?

6. What are the policy implications of the most robust findings 48and key uncertainties?

KEY QUESTIONS

IN THE MILLENNIUM

ECOSYSTEM ASSESSMENTElectron micrograph of avian influenza A (H5N1) viruses(seen in gold) grown in MDCK – canine kidney – cells(seen in green). Changes in poultry and livestockproduction have contributed to the emergence of avianinfluenza as a global public health concern (see Box 1.1).

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1.1 Introduction

n a fundamental sense, ecosystems are the planet'slife-support systems - for the human species and all

other forms of life (see Figure 1.1). The needs of thehuman organism for food, water, clean air, shelter andrelative climatic constancy are basic and unalterable. That is,ecosystems are essential to human well-being and especiallyto human health – defined by the World HealthOrganization as a state of complete physical, mental andsocial well-being. Those who live in materially comfortable,urban environments commonly take for granted ecosystemservices to health. They assume that good health derivesfrom prudent consumer choices and behaviours, with accessto good health care services. But this ignores the role of thenatural environment: of the array of ecosystems that allowpeople to enjoy good health, social organization, economicactivity, a built environment and life itself.

Historically, overexploitation of ecosystem services hasled to the collapse of some societies (SG3). There is anobservable tendency for powerful and wealthy societieseventually to overexploit, damage and even destroy theirnatural environmental support base. The agricultural-basedcivilizations of Mesopotamia, the Indus Valley, the Mayans,and (on a micro-scale) Easter Island all provide well-documented examples. Industrial societies, although inmany cases more distant from the source of the ecosystemservices on which they depend, may reach similar limits.

Resource consumption in one location can lead todegradation of ecosystem services and associatedhealth effects in other parts of the world (SG3). At itsmost fundamental level of analysis, the pressure onecosystems can be conceptualized as a function ofpopulation, technology and lifestyle. In turn, these factorsdepend on many social and cultural elements. Forexample, fertilizer use in agricultural productionincreasingly is dependent on resources extracted fromother regions and has led to eutrophication of rivers, lakesand coastal ecosystems.

Notwithstanding ecosystems' fundamental role asdeterminants of human health, sociocultural factors playa similarly important role. These include infrastructuralassets; income and wealth distribution; technologies used;and level of knowledge. In many industrialized countries,

changes in these social factors over the last few centuries haveboth enhanced some ecosystem services (through moreproductive agriculture, for instance) and improved healthservices and education, contributing to increases in lifeexpectancy. The complex multifactorial causation of states ofhealth and disease complicates the attribution of humanhealth impacts to ecosystem changes. A precautionaryapproach to ecosystem management is appropriate.

In many respects human health is a bottom-line (orintegrating) component of well-being, since changes ineconomic, social, political, residential, psychological andbehavioural circumstances all have health consequences.Basic determinants of human well-being may be defined interms of: security; an adequate supply of basic materials forlivelihood (e.g. food, shelter, clothing, energy, etc.);personal freedoms; good social relations; and physicalhealth. By influencing patterns of livelihoods, income,local migration and political conflict, ecosystem servicesimpact the determinants of human well-being. The waysin which health status may both reflect and influencehuman well-being are illustrated in Figure 1.2.

1.2 Current state of ecosystems andassociated human health status

Ecosystem services are indispensable to the well-beingof people throughout the world (SG3). The benefitsobtained from ecosystems include: food; natural fibres; asteady supply of clean water; regulation of some pests anddiseases; medicinal substances; recreation; and protectionfrom natural hazards such as storms and floods. The MAcategorizes ecosystem services as follows: provisioningservices, regulating services, supporting services andcultural services – each of which has several sub-categories(see Figure 1.3). The state of the environment andecosystems are modified by patterns of demographicgrowth, development and consumption, all of which mayreduce or increase (if only temporarily) the supply ofecosystem services.

The causal links between environmental change andhuman health are complex because often they areindirect, displaced in space and time and dependenton a number of modifying forces. For example, climatechanges can place stresses on agricultural production orthe integrity of coral reefs and coastal fisheries. This can

1. Why do ecosystems matter to human health?

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lead to malnutrition and related ailments. Deforestationmay alter disease patterns as well as local and regionalclimates, potentially affecting disease vector distributionsover time. Processes stemming from disruption ofecosystems may lead to the emergence or resurgence ofdisease, while local factors such as poverty, poorprevention and treatment and heightened susceptibility

may lead to local establishment of transmission. Whenthese events combine with human activities related toglobalization (such as international trade and travel)global pandemics can arise, as illustrated already by thedevelopment and spread of HIV/AIDS and, potentially,by the appearance in human populations of other newinfectious disease strains, e.g. avian influenza.

Figure 1.1 MA: conceptual framework

Changes in drivers that indirectly affect ecosystems, such as population, technology and lifestyle (upper right corner of Figure 1.1 ) can lead tochanges in drivers that directly affect ecosystems, such as fisheries' catches or fertilizer applications to increase food production (lower right corner).The resulting changes in the ecosystem (lower left corner) cause ecosystem services to change and thereby affect human well-being. Theseinteractions can take place at more than one scale and can cross scales. For example, a global timber market may lead to regional loss of forest cover,increasing flood magnitude along a local stretch of river. Similarly, interactions can take place across different timescales. Actions to respond tonegative changes or to enhance positive changes can be taken at almost all points in this framework (cross bars).


Figure 1.2 Associations between health, other aspects of human well-being and ecosystem services (R 16 Figure 16.1)

The MA identifies five main aspects of human well-being. This diagram makes health the central aspect. Human health is affected directly andindirectly by changes in ecosystems but also is affected by changes to other aspects of well-being. Lack of aspects of human well-being (i.e.material minimum, good social relations, security, freedom and choice) all can have health impacts. Health also can influence these other aspectsof human well-being.

1.2.1 Fresh waterOver 1 billion people lack access to safe water supplies;2.6 billion people lack adequate sanitation. This has ledto widespread microbial contamination of drinking-water (see Figure 1.4). Water-associated infectious diseasesclaim 3.2 million lives each year, approximately 6% of alldeaths globally. The burden of disease from inadequatewater, sanitation and hygiene totals 1.7 million deaths andthe loss of more than 54 million healthy life years.Investments in safe drinking-water and improved sanitationshow a close correspondence with improvements in human

health and economic productivity. Every day each personrequires 20-50 litres of water free of harmful chemical andmicrobial contaminants for drinking, cooking and hygiene.There remain substantial challenges to providing this basicservice to large segments of the human population (C7).

Fresh water is a key resource for human health. It is usedfor growing food, drinking, washing, cooking and thedilution and recycling of wastes. Globally, the amount offresh water available per person decreased from 16 800 m3 in1950 to 6800 m3 in 2000, as a result of population growth.


Figure 1.3 Categories of ecosystem service

Figure 1.3 depicts the strength of linkages between commonly-encountered categories of ecosystem services and components of human well-being, andincludes indications of the extent to which it is possible for socioeconomic factors to mediate the linkage. For example, the ability to purchase asubstitute for a degraded ecosystem service offers a high potential for mediation. The strength of the linkages and the potential for mediation differ indifferent ecosystems and regions. In addition to the influence of ecosystem services on human well-being depicted here, other factors influence humanwell-being including other environmental factors as well as economic, social, technological and cultural factors. In turn ecosystems are affected bychanges in human well-being.

One third of the world lives in countries experiencingmoderate to high water stress, a fraction that is increasing aspopulation and per capita water demand grow.

Water scarcity is a globally significant andaccelerating condition for 1-2 billion peopleworldwide, leading to problems with foodproduction, human health and economicdevelopment. A high degree of uncertainty surroundsthese estimates and they merit substantial further analysisin order to support sound water policy formulation and

management. Rates of increase in a key water scarcitymeasure (water use relative to accessible supply) from1960 to the present averaged nearly 20% per decadeglobally, with values of 15% to more than 30% perdecade for individual continents (C7).

The supply of fresh water safe for human use andconsumption has been reduced further by severepollution from anthropogenic sources. Over the pasthalf-century there has been an accelerated release ofartificial chemicals into the environment, many of which


Figure 1.4 Access to improved water and sanitation facilities globally

The top map shows the percentage of population using improved drinking-water sources. The lower map shows the percentage of population usingimproved sanitation. In regions of the world where a significant proportion of the population has no access to improved sanitation, the natural waterfiltration and purification services provided by ecosystems may be quickly overwhelmed by improperly disposed human waste. If this service is notreplaced by a reliable engineered filtration system or water supply, the result is likely to be high levels of diarrhoea and other water-borne diseasesAltogether, unsafe water, sanitation and hygiene were estimated to be responsible for approximately 1.7 million deaths in the year 2000.


are long-lived and transformed into by-products whosebehaviours, synergies and impacts are not well-known.Inorganic nitrogen pollution of inland waterways, forexample, has more than doubled globally since 1960 andincreased by a factor of over 10 for many industrializedparts of the world. Pollution impairs the ability ofecosystems to provide clean and reliable sources of water.Deterioration of fresh water quality is magnified incultivated and urban systems (high use, high pollutionsources) and in dryland systems (high demand for flowregulation, absence of dilution potential) (C7).

From 5% to possibly 25% of global fresh water useexceeds long-term accessible supplies and is now meteither through engineered water transfers or overdraftof groundwater supplies (low to medium certainty).Much of this water is used for irrigation, with irretrievablelosses in water-scarce regions. All continents record suchwithdrawals. In the relatively dry region of North Africaand the Middle East up to 30% of all water use isunsustainable (C7).

The effects of climate change on water resources aredifficult to forecast because of the many factors thatinfluence rainfall, runoff and evapotranspiration (R16).Temperature increases may worsen water quality byincreasing the growth of microorganisms and decreasingdissolved oxygen. Water-related disasters, such as droughtsand floods, also have important health impacts. Thefrequency of heavy rainfall events is likely to increase,leading to an increase in flood magnitude and frequency.Heavy rainfall tends to affect water quality adversely byincreasing the quantities of chemical and biologicalpollutants that are suddenly flushed into rivers and byoverloading sewers and waste storage facilities. In someparts of the world, climate change also may raiserequirements for irrigation water because of increasedevaporation. Climate change will affect the distribution andlength of transmission seasons for vector-borne diseases.

1.2.2 FoodFor maximum well-being, people must have access toand consume not only sufficient calories but also adiverse diet with sufficient protein, oils and fats,micronutrients and other dietary factors (C8). Averagedaily energy intake has declined recently in the poorestcountries. Inadequate energy intake is exacerbated by thegenerally low-quality diets of poor people. The world'spoorest populations generally rely on starchy staples for

energy, leading to significant protein, vitamin and mineraldeficiencies. Nutritional status and children's growth ratesimprove with consumption of greater food diversity,particularly of fruits and vegetables.

A global epidemic of diet-related obesity andnoncommunicable disease is emerging as increasinglyurbanized populations adopt diets that are higher inenergy and lower in diversity of fruits and vegetablesthan those consumed traditionally (C8). Many poorcountries now face a double burden of diet-related disease:the simultaneous challenges of significant incidence ofcommunicable diseases in poor and undernourishedcommunities and an increasing incidence of chronicdiseases associated with the overweight and obese,especially in richer and less physically active subsections ofthe populations, often in urban areas. The pathway fromtraditional rural diets to those of increasingly urban andaffluent societies and the attendant implications fornutrition and health has been dubbed the nutritiontransition or the diet transition.

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In poor countries, especially in rural areas, people's healthis highly dependent on the services of local productiveecosystems for food (R16). Aggregate food productioncurrently is sufficient to meet the needs of all, yet of thepresent world population of over 6 billion, over 800 millionconsume insufficient protein or calories to meet dailyminimum requirements. Similar numbers are overfed, oftenwith diets that are high in energy but lacking in diversity.Several billion people experience micronutrient deficiency. Inricher urban communities, human dependence on ecosystemsfor nourishment is less apparent but no less fundamental.

The nutritional imbalance between rich and poor hasbeen driven primarily by social factors, though ecologicalfactors may play an increasingly important role in thefuture (R16). Undernutrition is related strongly to poverty;in the poorest countries with the highest mortality rates,between one-sixth and one-quarter of the burden of disease isrelated to childhood and maternal undernutrition (see Figure

1.5). Worldwide, undernutrition accounts for nearly 10% ofthe burden of disease. In developed countries with lowmortality rates, diet-related risks (mainly overnutrition, incombination with physical inactivity) account for betweenone-tenth and one-third of the burden of disease, mainlythrough conditions such as hypertension, coronary heartdisease and diabetes. Population health considerations haveimportant implications for agricultural policy.

Local food production is critical for eliminating hungerand promoting rural development in areas where thepoor do not have the capacity to purchase food fromelsewhere (C8). In regions such as sub-Saharan Africa, twothirds of the population relies on agriculture or agriculture-related activities for their livelihood. At the same time, thenumber of food-insecure people is growing fastest in poorcountries where underdeveloped market infrastructures andlow per capita income prevent food needs from beingsatisfied through globalized chains of food production and


Figure 1.5 Map of child mortality

The poorest countries have the highest rates of child deaths, particularly from environmental hazards.


supply. In these areas, local food production is critical foreliminating hunger and providing insurance against risingfood prices. When household food surpluses are marketedlocally, such production may be a generator of employmentand economic benefits. Subsistence agriculture thus canprovide a nutritional baseline and social safety net for ruralfamilies – alongside income-oriented agricultural production(cash crops) – and enhance health.

The accelerating demand for livestock productsincreasingly is being met by intensive (industrial orlandless) production systems, particularly for chickensand pigs, and especially in Asia (C8). These highly

modified systems have contributed to large increases inproduction but pose a range of risks to ecosystems andhuman health. These include the generation of high levels ofwaste, increased pressure on cultivated systems to providefeed inputs with consequent increased demand for water andnitrogen fertilizer, as well as the risk of outbreaks of infectiousdisease such as BSE, SARS and avian flu (see Box 1.1).

In poor countries (excluding China), per capita fishconsumption declined between 1985 and 1997 (C18).Pressure on marine ecosystems is increasing to the pointwhere wild fisheries are near or exceeding their maximumsustainable levels of exploitation. World fish catches have

Box 1.1 Pigs, poultry and people

Many important human diseases (includinginfluenza, tuberculosis and measles) arezoonoses that long ago became establishedwithin human populations after crossingfrom domesticated animal species includingchickens, cattle and dogs (C14). Modern,intensive farming practices in associationwith trade, travel and ecological change, areimplicated in the emergence of diseasesincluding BSE, foot-and-mouth disease andNipah virus.Probably the zoonosis of greatestcontemporary concern for public health isavian influenza, which has been reportedrecently to be spreading from Asia. Thisvirus has the potential to mutate, or to swapor reassort genes with coinfecting influenzaviruses circulating in human populations,and among wild or domesticated birds,leading to new, highly virulent strains thatcould be transmitted directly betweenhumans. The close cohabitation of poultryand people in poor rural areas creates greatpotential for infection. In addition, currentpoultry production patterns (an ecosystemwhich could never exist in nature) andinternational movement of both birds andpeople, facilitate the amplification andspread of the disease. Despite vaccinationand the periodic culling of infected flocks,the risk of human infection persists.

In recent years, outbreaks of Nipah virushave been reported in Malaysia, Singapore,Bangladesh and India. In the Malaysianoutbreak, which killed more than 100

people, the causal webincluded an expandinghuman population, poorgovernance, climate change,illegal land clearing, forestfires and intensive animalhusbandry. The path of contagion hasbeen traced back tomigrations of bats fromIndonesia to neighbouringMalaysia, beginning around1998. This followed anintense El Niño dry spell,which coincided with theillegal burning by farmers oflarge sections of Indonesianforest, particularly in theSumatra and Kalimantanregions, in 1997 and 1998,to clear land for plantations. The intensesmoke and haze, which persisted formonths, forced the migration of flocks ofbats, infected with a previously unknownvirus, to neighbouring Malaysia. Here theycame into contact with intensively-farmedpigs. The pigs developed a respiratoryillness, transmitted directly to other pigsand humans. Many pigs were culled in orderto limit the spread of the virus. No human-to-human transmission was proven. Morerecently, an outbreak of Nipah virusoccurred in Bangladesh. The causalpathway there is less well-investigated andunderstood, but may involve direct human

exposure to bat droppings. An epidemic of Japanese encephalitis in SriLanka has been attributed, in part, to thepromotion of smallholder pig husbandry inan attempt to generate supplementaryincome among rice farmers in an irrigatedecosystem that increased the habitat forvectors. Diseases affecting flocks and herdsalso can impose a high human cost, botheconomic and psychological, upon animalhusbandry workers who depend on theinfected animals for their livelihoods. This isthe case especially when animals areuninsured or when large numbers ofanimals are culled.

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been declining since the early 1990s due to overexploitation.Inland water fisheries, which are particularly important inproviding high-quality diets for poor people, also havedeclined due to habitat modification and water abstraction.

Wild foods are locally important in many developingcountries, often bridging the hunger gap created bystresses such as droughts and civil unrest (C8). Inaddition to fish, wild plants and animals are importantsources of nutrition in some diets and have significant value,although this is not captured by conventional economicmeasures. The capacity of ecosystems to provide wild foodsources generally is declining, as natural habitats worldwideare under increasing pressure, and as wild plant and animalpopulations are exploited for food at unsustainable levels.Agricultural intensification and the 'simplification', e.g.increased uniformity and decreased biodiversity, ofagricultural landscapes, can limit the availability of, andaccess to, wild foods and food plants growing as weeds.These may be of nutritional importance, especially tolandless poor people and vulnerable groups withinhouseholds. Similarly the decline of traditional fisheries (dueto commercial exploitation of coastal fisheries and damageto inland water ecosystems due to water extraction anddiversion) can have severe negative nutritional and healthconsequences in poor countries.

1.2.3 Timber, fibre and fuel Timber exploitation has contributed to ecosystemdegradation and associated health effects in manyregions of the developing world (C9). Demand for timberhas led to widespread deforestation in tropical rainforests.This is associated with high rates of occupational injuriesand exposure to infectious diseases, such as malaria, amongworkers and families in the Amazon rainforest. Over thelonger term, deforestation can lead to transmission cycles of

vector-borne diseasestransferring from theforest to the domesticenvironment,increasing diseaseburdens for womenand childrenparticularly.

Power generation has a range of health impacts (R16).Outdoor air pollution is caused predominantly by thecombustion of non-renewable fossil fuels for electricitygeneration, transport and industry. Globally, urban airpollution is responsible for significant mortality andmorbidity every year, largely as a result of heart and lungdiseases. The accompanying release of a major greenhousegas (CO2) and its consequent contribution to globalwarming have further, mostly adverse, impacts on humanhealth. Air pollution due to forest fires and burningpractices in agriculture also can have serious local andregional health consequences. This was highlighted by thepublic health experiences in south-east Asia in 1998,following widespread drought-associated forest fires inSumatra and Kalimantan, Indonesia (see Box 1.1). Indoorair pollution from the combustion of solid fuels,including biomass (e.g. wood, crop stubble, and animaldung) and coal, in poorly ventilated heating and cookingenvironments, is responsible for significant respiratorydisease and deaths globally, particularly among children.Over half of the world’s population relies upon solid fuelsfor cooking and heating (see Figure 1.6). In areas wherethe demand for wood has surpassed local supply andalternative energy sources are either unavailable or tooexpensive, the shortage of biomass fuel can lead to avariety of other health impacts, including: increasedvulnerability to illness from exposure to cold, andincreased vulnerability to food and water-borne diseasesfrom improper heating of food and water. Increasedincidence of food- and water-borne diseases can, in turn,contribute to malnutrition. Poor women and children inrural communities often are the most affected byfuelwood scarcity. Many must walk long distancessearching for and carrying firewood (often water too) andtherefore have less time and energy for tending crops,cooking meals or attending school. For these reasons,adequate energy supplies are fundamental to sustainabledevelopment.

1.2.4 Biological productsMillions of people around the world depend partly orfully on products collected from ecosystems formedicinal purposes (R16). Even when syntheticmedicines (often originating from natural sources) areavailable, the need and demand for wild products persists.Some of the better-known pharmaceuticals from naturalsources include aspirin, digitalis and quinine.


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Figure 1.6 Percentage of households using solid fuel for cooking

Most of the world's population uses solid fuels, including both biomass and coal, to meet their basic energy needs, often cooking and heating uponopen fires or rudimentary stoves. The resulting indoor smoke is responsible for significant morbidity and mortality from respiratory disease.

1.2.5 Nutrient and waste management, processingand detoxification

Humans are at risk from inorganic chemicalcompounds and persistent organic pollutants presentin food and water (C7, R16). Contamination caninfiltrate from natural sources (as in the case of arseniccontamination of water in tube wells in Bangladesh)and from human actions resulting in the release of toxicchemicals into the environment (for example, throughpesticide use). Toxic chemicals can cause a variety ofadverse health effects. Low-level exposure to somechemicals present in industrial effluent or used aspesticides, such as PCBs, dioxins and DDT, may causeendocrine disruption, undermining disease resistanceand reproduction. They are also responsible for moreacute health impacts, including poisonings.The presence of pharmaceutical products or residues inthe environment is a related emerging environmental

issue. Pharmaceutical residues may be released throughsewage and solid waste disposal and removed onlypartially by conventional biological treatment. As a result,they can be detected in sewage treatment plant effluentsand in receiving waters, posing health risks that have notyet been quantified.

Nutrient depletion, e.g. as a result of inadequate soilconservation practices, can impair soil fertility resultingin lower crop yields, which in turn may negatively affectthe nutritional status of farm households. Dietarydeficiencies (in terms of both macro- and micro-nutrients)have been demonstrated to harm children's physical andmental growth. The economic and livelihood impacts onfarmers may also impinge on their ability to secure adequateeducation and health services for themselves and theirchildren, limiting their future options.

While ecosystems provide effective mechanisms forcleansing the environment of wastes, this service is nowovertaxed in many settings, leading to local andsometimes global waste accumulation (C15). Well-functioning ecosystems absorb and remove contaminants; forexample, wetlands can remove excess nutrients from sewagerunoff, preventing damage to ecosystems downstream. Ifexcessive wastes are discharged into ecosystems, wastetreatment technologies are required to restore or preserveecosystem balance, and thus reduce or eliminate the risks tohuman health. When recycled appropriately, human wastecan be a useful resource that promotes soil fertility. However,where waste contains persistent chemicals such asorganochlorines or heavy metals, recycling can lead to theaccumulation of these pollutants and increased humanexposures through food and water. In poor countries, nearlyall sewage and most industrial wastes are dumped untreatedinto surface water. It is uncertain whether the wastedetoxification capabilities of the planet as a whole areincreasing, decreasing, or reaching a critical threshold atwhich such services may no longer function effectively.

Sustained increases in nitrogen and phosphorus loadingof ecosystems due to land-based human activities arecontributing to the deterioration of water quality overmany of the globe's inhabited regions (C7). Fertilizer useis the major contributor to this problem. Excessive fertilizerrunoff into lakes and streams can upset the balance ofnutrients in lakes and rivers, facilitating the growth of certainalgal plants, including some that are toxic to humans.Eutrophication, the process whereby excessive plant growthdepletes oxygen in the water, can negatively impact other

forms of aquatic life, e.g. fish, and thus food sources, creatingrisks to human health and well-being.

1.2.6 Regulation of infectious disease The magnitude and direction of altered infectious diseaseincidence due to ecosystem changes depend on thecharacteristics of the particular ecosystems; type of land-use change; disease-specific transmission dynamics; andthe susceptibility of human populations (C14). Infectiousdisease risks are affected particularly by destruction of, orencroachment into, wildlife habitat, particularly throughlogging and road building; changes in the distribution andavailability of surface waters, such as through damconstruction; irrigation and stream diversion; and agriculturalland-use changes, including proliferation of both livestockand crops.

The reasons for the emergence or re-emergence of somediseases are unknown, but the main biologicalmechanisms that have altered the incidence of manyinfectious diseases are clear: altered habitat features leadingto changes in the number of vector breeding sites or reservoirhost distribution; niche invasions of new species orinterspecies host transfers; changes in biodiversity, includingloss of predator species and changes in host populationdensity; human-induced genetic changes of disease vectors orpathogens (such as mosquito resistance to pesticides oremergence of antibiotic-resistant bacteria); andenvironmental contamination by infectious disease agents(C14). Numerous disease/ecosystem relationships illustratethese biological mechanisms.


Box 1.2 Can biodiversity regulate infectious diseases?

Many other infectious diseases have been,or are potentially, transmissible to humansfrom wild animals, either directly or viainsect vectors. Others are transmittedbetween humans by vectors, e.g. malaria.Close contact with bushmeat is believed tohave led to the first transmission of HIV tohumans. SARS may have entered thehuman population via wild species, alsoraised domestically, and consumed as foodin China. It is clear that ecosystem change,including changed biodiversity, influencesthe risk of transmission of many diseasesto humans (C14). For example, the

increased transmission of Lyme disease inrecent years partly is due to increasedrodent populations, the most importantreservoir of the causative organism of thistick-borne disease. Other zoonotic diseasesaffecting humans include West Nile virusand Hendra virus.

Many ecosystem changes can alter thehabitats, and hence populations, ofdisease-transmitting vectors. Such changesmay include: forest clearance; constructionof dams, or irrigation and canal networks;and deliberate or inadvertent water

collection (e.g. in debris). However, thetransmission of major infectious vector-borne diseases such as malaria and yellowfever can never be described as entirelyecosystem-dependent, but rather as afunction of human interactions andecosystem services. Along with improvedmanagement of ecosystem services, otheractions (e.g. public education, medical andchemical interventions, and povertyalleviation), all play a role in reducing, andin some cases eliminating, diseasetransmission.


Box 1.3 Infectious diseases related to ecosystem disturbance

Disturbance or degradation of ecosystems can have biological effects that are highly relevant to infectious disease transmission (C14).The reasons for the emergence or re-emergence of some diseases are unknown, but the following mechanisms have been proposed:• altered habitat leading to changes in the number of vector breeding sites or reservoir host distribution;• niche invasions or transfer of interspecies hosts;• biodiversity change (including loss of predator species and changes in host population density);• human-induced genetic changes in disease vectors or pathogens (such as mosquito resistance to pesticides or the emergence of

antibiotic-resistant bacteria); and• environmental contamination by infectious disease agents (such as faecal contamination of source waters).

Cryptosporidium parvumColoured scanning electron micrograph (SEM) of the surface of the smallintestine infected with Cryptosporidium parvum parasites (red), cause ofcryptosporidiosis. The parasite develops in the protrusions (microvilli) ofepithelial cells that line the intestinal wall. Severe infection causes thefolds of the intestinal wall to fuse and atrophy. Infection typicallyproduces mild symptoms of diarrhoea, fever and headache. However, inthe immuno-compromised, such as those with AIDS (acquired immunedeficiency syndrome), infection can be fatal.

Dams and irrigation canals provide ideal habitats forsnails that serve as the intermediate reservoir host speciesfor schistosomiasis. Irrigated rice fields increase the extentof mosquito breeding areas, leading to greatertransmission of mosquito-borne malaria, lymphaticfilariasis, Japanese encephalitis, and Rift Valley fever.Deforestation alters malaria risk, depending on the regionof the world. Deforestation has increased the risk ofmalaria in Africa and South America, but the effect insouth-east Asia is very uncertain. Natural systems with intact structures and characteristicsgenerally resist the introduction of invasive human andanimal pathogens brought by human migration andsettlement. This seems to be the case for cholera, kala-azarand schistosomiasis, which have not become establishedin the Amazonian forest ecosystem.Uncontrolled urbanization of forest areas has beenassociated with mosquito-borne viruses (arboviruses) inthe Amazon and lymphatic filariasis in Africa. Tropicalurban areas with poor water supply systems and lack ofshelter promote transmission of dengue fever.Zoonotic pathogens, e.g. pathogens completing theirnatural life-cycle in animal hosts, are a significant cause ofboth historical diseases (such as HIV and tuberculosis)and newly emerging infectious diseases affecting humans(such as SARS, West Nile virus and Hendra virus) (seeBox 1.2.)

Intensive livestock management practices that includeroutine, sub-therapeutic use of antibiotics havecontributed to the emergence of antibiotic-resistantstrains of Salmonella, Campylobacter and Escherichia colibacteria. Overcrowding of livestock and the mixing oflivestock breeds that may occur in intensive meatproduction, as well as trade in wild, undomesticatedanimals (bushmeat), can facilitate interspecies hosttransfer of disease agents. This, in turn can lead to theemergence of dangerous novel human pathogens such asSARS and new strains of influenza (see Box 1.3).

Major trade-offs may exist between infectious disease riskand certain kinds of development projects geared towardsincreasing food production, power generation capacity,and economic growth (C14). The infectious diseases ofmajor public health importance that require special attentiondue to ecosystem changes, but also have the greatest potentialfor risk reduction by planned interventions include: malaria,across most ecological systems; dengue fever in tropical urbancentres; schistosomiasis and filariasis in cultivated and inlandwater systems in the tropics; leishmaniasis in forest anddryland systems; cholera in coastal and urban systems;cryptosporidiosis in agricultural systems; Japaneseencephalitis in agricultural systems; and West Nile virus andLyme disease in urban/suburban systems of Europe andNorth America (see Table 1.1).

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Table 1.1 Infectious diseases and mechanisms of potential changing incidence as related to ecosystem changes - some examples (C14)

DALYsa (Proximate) (Ultimate) Emergence Geographical Sensitivity toDisease (thousand) Emergence driver distribution ecological change Confidence level

mechanism

Malaria 46 486 niche invasion, deforestation, water tropical (America, + + + + + + +vector expansion projects Asia and Africa )

Dengue fever 616 vector expansion urbanization, poor housing tropical + + + + +forest encroachment,

HIV 84 458 host transfer bushmeat hunting, human global + + +behaviour

host transfer, deforestation, agricultural tropical Americas,Leishmaniasis 2090 habitat alteration development Europe and Middle + + + + + + +

Eastdepletion of

Lyme disease predators, biodiversity habitat fragmentation North America + + + +loss, reservoir Europe

expansion

Chagas disease 667 habitat alteration deforestation, urban Americas + + + + +sprawl and encroachment

Japanese 709 vector expansion irrigated rice fields south-east Asia + + + + + +encephalitisWest Nile virus and other Americas, Eurasia + + +encephalitidesGuanarito, Junin biodiversity loss, monoculture in agriculture South America + + + + +and Machupo reservoir expansion after deforestationvirusesOropouche / forest encroachment,Mayaro viruses in vector expansion urbanization South America + + + + + +Brazil

variations inHantavirus population density of climate variability + + + +

natural food sources

Rabies biodiversity loss, deforestation and mining tropical + + + +altered host selection

Schistosomiasis 1702 intermediate host dam building, irrigation America, Africa, + + + + + + + +expansion Asia

Leptospirosis global (tropical) + + + + +

Cholera b sea surface climate variability and global (tropical) ++ + + +temperature rising change

poor watershedCryptosporidiosis b

contamination by management where global + + + + + + +oocytes livestock exist

Meningitis 6192 dust storms desertification Saharan Africa + + + +Coccidioidomycosis disturbing soils climate variability global + + + + +Lymphatic 5777 tropical Americafilariasis and Africa + + + +

Trypanosomiasis 1525 Africa

Onchocerciasis 484 Africa, tropical + + + + +America

Rift Valley fever heavy rains climate variability and Africachange

industrial food production, Australia, Nipah/Hendra niche invasion deforestation, climate south-east + + + +viruses abnormalities Asia

a Disability-adjusted life years. b Both cholera and cryptosporidiosis contribute to the loss of nearly 62 million DALY’s annually from diarrhoeal diseases. Key: + = low; + + = moderate; + + + = high; + + + + = very high.

1.2.7 Cultural, spiritual and recreational servicesCultural services provided by ecosystems may be lesstangible than material services. Nonetheless suchservices are highly valued by all societies (R16). Peopleobtain diverse non-material benefits from ecosystems,including recreational opportunities and tourism,aesthetic appreciation, inspiration, a sense of place andeducation. Traditional practices linked to ecosystemservices play an important role in developing social capitaland enhancing social well-being.

There is a hypothesis that stimulating contact with therich and varied environment of ecosystems, includinggardens, may benefit physical and mental health. There islimited evidence that this may help in the prevention andtreatment of depression, drug addiction and behaviouraldisturbances as well as convalescence from illness orsurgery. Regular contact with pets seems to prolong andenhance the quality of life, especially in old age. Beneficialcontact with nature need not be physical and tactile. Forexample, there is some evidence that certain benefits maybe obtained from visual or visualized contact.

1.2.8 Climate regulationEach of the ecological services described above issensitive to climate and will be affected byanthropogenic climate change (R16). Although climatechange will have some beneficial effects on human health,most are expected to be negative. Direct effects, such asincreased mortality from heatwaves, are most readilypredicted but indirect effects are likely to predominate.Human health is likely to be affected indirectly byclimate-induced changes in the distribution of productiveecosystems and the availability of food, water and energysupplies. In turn, these changes will affect the distributionof infectious diseases, nutritional status and patterns ofhuman settlement. Changes in the geographicaldistribution, abundance and behaviour of plants andanimals affect, and are affected by, biodiversity, nutrientcycling and waste processing.

Extreme weather events (including floods, storms anddroughts) and sea-level rise are expected to increase asa result of climate change (R16). These have local andsometimes regional effects: directly through deaths andinjuries; indirectly through economic disruption,infrastructure damage and population displacement.Changes in land cover affect flood frequency andmagnitude, but the degree and extent of this impact is

highly dependent on the characteristics of the localecosystem and the nature of the land cover change.Health effects of climate extremes include: physicalinjuries; increases in communicable diseases resultingfrom crowding; lack of safe water and shelter; poornutritional status; and adverse effects on mental health.

Globally, the annual absolute number of peoplekilled, injured or made homeless by natural disastersis increasing (R16). An important reason for this is thegrowth of human settlements in coastal zones and onfloodplains that are particularly exposed to extremeevents. Case studies have shown that environmentaldegradation has reduced the capacity of certain ecosystemsto serve as a buffer against climate extremes. For example,degraded or damaged coral reefs and mangroves may losetheir capacity to stabilize coastlines and limit thedamaging effect of storm surges. Landslides may be morelikely to occur on deforested slopes following heavyrainfall. In many areas, the only land available to poorhouseholds and communities may also be highlyvulnerable to impacts from weather extremes.

In recent decades, most regions of the worldexperienced significant human migration from ruralareas to cities. More than half of the world'spopulation now lives in high-density urban areas,many of which are poorly supplied with eitherecosystem or human services. Such migration andincreasing vulnerability means that even without growingnumbers of extreme events, losses attributable to eachevent will tend to increase. There is particular concern forthe sustainability of the livelihoods of the inhabitants ofsmall island states. These locales provide an example ofpopulations experiencing increasing climate variability,sea-level rise and loss of biodiversity, with associatedimpacts on health and well-being.

Natural ecosystems play an important role inregulating climate, mainly by acting as sinks forgreenhouse gases (C13). Ecosystems, both natural andmanaged, exert a strong influence on climate and airquality as sources and sinks of pollutants, greenhousegases and suspended dust (aerosols), due to physicalproperties that affect the flows of energy and rainfall.Ecosystems can affect climate in numerous ways: in termsof warming, as sources of greenhouse gases; and in termsof cooling, as sinks of greenhouse gases. Climatic heatingand cooling mechanisms also are influenced by albedo, or


ecosystem reflectivity to solar radiation, e.g. forests absorbheat energy, and thus have lower albedo than snow, whichreflects solar radiation. Natural aerosols (e.g. dust) alsoreflect solar radiation. Ecosystems affect climate throughpatterns of evapotranspiration and cloud formation, waterredistribution/recycling, and regional rainfall. Ecosystemsaffect air quality through interactions with atmosphericcleansing processes (e.g. as sinks for air pollutants andsources of pollution such as particulates from biomasscombustion); and through nutrient redistribution (e.g.fertilizing effects of nitrogen deposition, carbon dioxideand dust).

Health risks from climate change are expected to increase(C13, R16). Human activities are responsible for an annualemission of an estimated 7.9 billion tonnes of carbon dioxideto the atmosphere. Reforestation and changes in agriculturalpractices in temperate regions in the past few decades haveenhanced global capacity to absorb this carbon, but notsufficiently to halt climate change. Reducing anthropogeniccarbon emissions is critical to the mitigation of climatechange. Enhancing or maintaining the capacity of ecosystemsto absorb carbon is similarly important.

Ecosystem management has the potential to modifyconcentrations of a number of greenhouse gases,although this potential is likely to be small incomparison to the potential growth in fossil fuelemissions over the next century, as predicted in scenariosdeveloped by the Intergovernmental Panel on ClimateChange (IPCC) [high certainty] (C13). In their activegrowth phase, forests are the terrestrial ecosystems mosteffective in capturing carbon dioxide, the greenhouse gasresponsible for the most significant share of global warmingimpacts. However, such forests must be maintained intact inorder to serve as effective sinks. In general, when a forest iscleared it is replaced by land uses that capture and containless than half of the carbon that was stored by the forest.


Electron micrograph ofparticulate matter sampled on afilter near a street; diesel soot(small grey spheres) dominatesthe sample. Salts and mineralsare in green and pinkishcrystalline forms.

Air pollution does not affect health alone; it can reduce farm productivity by shielding crops from sunlight. The image to the left, similar to a digital photograph, shows a natural-colourview of thick haze over the agricultural regions north of the Yangtze River in eastern China, 28 February 2005. The image to the right uses short-wave and near-infrared observationsto reveal the green winter crops, mostly wheat and rice (close to the Yangtze River), underneath the haze. Water is deep blue or brighter blue when sediment levels are high.

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he structure and functioning of the world’secosystems changed more rapidly in the second

half of the twentieth century than over anycomparable period in human history. Humans arefundamentally, and to a significant extent irreversibly,changing the diversity of life on Earth and most of thesechanges represent a loss of biodiversity. Most changes toecosystems have been made to meet a dramatic growthin the demand for food, water, timber, fibre and fuel.

More land was converted to cropland in the 30 yearsafter 1950 than in the 150 years between 1700 and1850 (C26). Cultivated systems - areas where at least30% of the landscape is in croplands, shiftingcultivation, confined livestock production orfreshwater aquaculture - now cover one quarter ofEarth’s terrestrial surface.Roughly 20% of the world’s coral reefs were lost andan additional 20% degraded in the last severaldecades of the twentieth century (C19). The amount of water impounded behind dams hasquadrupled since 1960; reservoirs now hold three tosix times as much water as natural rivers. Waterwithdrawals from rivers and lakes have doubled since1960. Most water use (70% worldwide) is foragriculture.Since 1960, flows of reactive (biologically available)nitrogen in terrestrial ecosystems have doubled andflows of phosphorus have tripled.Since 1750, the atmospheric concentration of carbondioxide has increased by about 32% (from about 280ppm to 376 ppm in 2003).

In the aggregate, and for most countries, changesmade to the world’s ecosystems in recent decades haveprovided substantial benefits (C5). Many of the mostsignificant changes to ecosystems have been essential tomeet growing needs for food and water. These havehelped to reduce the proportion of malnourished peopleand improve human health. However, these gains havebeen achieved at growing costs in the form of thedegradation of many ecosystem services; increased risks oflarge, non-linear changes in ecosystems; exacerbation ofpoverty for some; and growing inequities and disparitiesacross groups of people.

Human well-being is affected by changes in thecomposition, functioning and flow of ecosystemservices. Management of an ecosystem to achieve aparticular goal (such as food, timber production or floodcontrol) generally results in changes to other ecosystemservices. These changes are not always taken intoaccount in planning, but they sometimes havesignificant impacts on human health.

Poor populations are more vulnerable to adversehealth effects from both local and globalenvironmental changes. Richer populations exertdisproportionate pressure on global ecosystems butare less vulnerable (R16). At present, major inequalitiesexist in access to ecosystem services. The status, or state,of these services is interlinked strongly with othercomponents and determinants of poverty such asincome, health and security. At the local level, povertyand the lack of access to clean, sustainable and efficientmeans for extracting ecosystem services can lead to localenvironmental degradation, with associated health risks.Also, poorer populations often live in environments thatare more prone to infectious and other diseases, andhave fewer resources for prevention and treatment.Richer populations have reduced health vulnerability toecosystem degradation, partly because they are able toimport resources from, and displace health risks to,other locations.

Many of the people and places affected adversely byecosystem changes and declining ecosystem servicesare highly vulnerable and ill-equipped to cope withfurther losses (C6). Human alterations of ecosystemsand their services shape the threats to which people andplaces are exposed and their vulnerability to those


2. How have ecosystems changed andwhat are the health implications?

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threats. The same alterations of environment can havevery different consequences, with reference to thedifferential vulnerability of the dependent social andecological systems. For example, disease emergence andre-emergence due to altered ecosystems can occur inboth rich and poor countries, and on any continent.Nonetheless, people in the tropics are more likely to beaffected in the future due to their greater exposure tosuch diseases and the greater scarcity of resources to copewith such ecosystem alterations and disease outbreaks insuch regions (R16). Highly vulnerable groups includethose whose needs for ecosystem services already exceedthe supply, such as people lacking adequate safe watersupplies or living in areas with declining agriculturalproduction (including a number of regions in Africa).

Vulnerability has increased as a result of the growthof populations in living ecosystems that are at greaterrisk from extreme weather or natural disasters, e.g.populations in low-lying coastal areas at risk offlooding, and populations in dryland ecosystems atrisk of drought. Partly as a result of this, the number ofnatural disaster victims requiring international assistancehas quadrupled over the past four decades. Finally,vulnerability is increased if either social or ecologicalresilience is diminished, e.g. through the loss of drought-resistant crop varieties; loss of farming expertise; or lossof institutional capacity to provide environmentalmanagement and health services that help protect localpopulations.

Historically, poor people disproportionately have lostaccess to ecosystem services as demand fromwealthier populations has grown (C6, R19). Coastalhabitats that primarily supported the food andlivelihood needs of local populations often are convertedto intensive aquaculture ponds or sites where speciessuch as shrimp and salmon are cultured primarily forexport markets. While some coastal residents may gainemployment and income from these enterprises, othersmay lose access to cheap protein or alternative sources oflivelihoods. Many areas where overfishing is a concernalso are low-income, food-deficit countries. For example,many west-African countries support large distant waterfleets that catch significant quantities of fish. Most ofthese fish are exported or shipped directly to Europe,yielding little direct benefit to the nutritional needs oflocal populations.

In poor countries (excluding China), per capita fishconsumption declined between 1985 and 1997 (C18).In some areas fish prices for consumers have increasedfaster than the cost of living. Fish products are tradedheavily (approximately 50% of fish exports are from poorcountries) and exports from poor countries and thesouthern hemisphere presently offset much of theshortfall in European, North American and east-Asianmarkets.

The regions facing the greatest challenges in achievingthe MDGs also tend to be the regions facing the mostserious problems in the ecologically sustainablesupply of ecosystem services (R19.ES). Many of theseregions include large areas of drylands, in which acombination of demographic growth and landdegradation is increasing human vulnerability to botheconomic and environmental change. In the last 20 years,these regions have experienced some of the highest ratesof forest and land degradation in the world.


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Over 1 billion people survive on incomes of less thanUS$ 1 per day, mostly in rural areas where they arehighly dependent on agriculture, grazing and huntingfor subsistence (R19). Although the wealthy arerelatively well-buffered from changes in some ecosystemservices, their mismanagement or overuse of those sameservices directly threatens the survival of poor people.Ecosystem conditions have a relatively direct and clearinfluence on human well-being in poor countries, asshown by the strong relationship between well-beingindicators such as the infant mortality rate and ecosystemtype in regions such as sub-Saharan Africa and Asia. Incontrast, in high-income societies, for instance OECDcountries, there is relatively little difference in infantmortality rates across populations living in a wide range ofecosystems (C6).

Diminished human well-being tends toincrease immediate dependence onecosystem services, and the resultantadditional pressure can damage furtherthe capacity of ecosystems to deliveressential services (SG2). As human well-being declines, there is a correspondingdecline in the options available for people toregulate their use of natural resources atsustainable levels. This increases pressure onecosystem services and can create adownward spiral of increasing poverty andfurther degradation of these services.

Within and between countries, poverty is aconsistent underlying determinant ofundernutrition and of diseases caused bylack of access to safe water, improvedsanitation and other public services (R16).Over 90% of the world's undernourishedpopulation lives in poor countries (C8). SouthAsia and sub-Saharan Africa, the regions withthe largest numbers of undernourishedpeople, also are the regions where per capitafood production has lagged the most.

Poverty and hunger have tended to force rural peopleonto marginal drought-prone lands with poor soilfertility; others have been forced to move to urbanslums (R16). About 1 billion people are affected by landdegradation caused by soil erosion, waterlogging orincreased salinity of irrigated land. Erosion has caused asubstantial reduction in crop yields in Africa.

In Africa, Asia and Latin America, 25–50% of thepopulation lives in informal or illegal settlementsaround urban centres with few or no public servicesand no effective regulation of pollution or ecosystemdegradation (C7). In many countries, local or regionalauthorities provide water and sanitation services only ifproof of landownership is provided. Other problems existin the provision of water and sanitation services to urbanslums and peri-urban settlements. These include: thedistance of such settlements from existing water andsewage networks; the cost of developing necessaryinfrastructure; rapid growth of such settlements, theirirregular development; and the limited ability of manyhouseholds to pay connection charges or monthly fees –unless the service is subsidized by the state.

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Rapid, uncontrolled urban growth in Africa, Latin America and Asia has contributed to ecosystemdegradation and increased pollution, with consequent health impacts.


Box 3.1 Scenario exercises

Scenarios are plausible, challenging andrelevant stories about how the futuremight unfold that can be told in bothwords and numbers (S2). They are notforecasts, projections or predictions andusually are not assigned probabilities,including those within the MA. Scenariosattempt to envision future pathways,including critical uncertainties andthresholds. They also try to provokequestions, widen perspectives andilluminate key issues, thereby supporting

more informed and rational decision-making.Previous global scenario exercises havefocused on social, economic and someenvironmental drivers but largely haveomitted important aspects of ecology andhealth. The MA scenarios, developed by aniterative process over several years,explicitly have included ecological changein both the quantitative models and thestorylines (S3). In addition, they haveenabled a first-order attempt to assess

future health.Scenarios are based on a coherent andinternally consistent set of assumptionsabout key driving forces and relationships.They are constrained within “riverbeds” oflikelihood. Many principles act toconstrain plausible futures. These includethe laws of physics, the principles ofeconomics, demographic inertia andplausible rates of technological and socialevolution and adaptation.

3. How might ecosystems change and what would be the health implications?

here is a dynamic interaction, growing rapidly inscale, between people and ecosystems. Although

understanding of these issues is expanding, the near tomid-term future of these linked elements is permeated bycomplexity, uncertainty, surprise and contest. Against this range of variables, scenarios are nonetheless atool useful in exploring an otherwise impenetrable future.

The MA developed four scenarios to explore plausiblefuture changes in drivers, ecosystems, ecosystemservices and human well-being: (i) GlobalOrchestration: globally-driven development patterns, withan emphasis on economic growth, social responsibilityand access to public goods; (ii) Order from Strength:regionalized development orientation, with emphasis onnational security and economic growth; (iii) AdaptingMosaic: regionalized development orientation, with anemphasis on local adaptation and flexible governance; and(iv) TechnoGarden: globally driven development patterns,emphasizing scientific innovations and green technologies(see Box 3.1 for a general description of scenarios). Thesescenarios were not designed to explore the entire range ofpossible futures for ecosystem services; other scenarioscould be developed that would have more optimistic ormore pessimistic outcomes for ecosystems, their servicesand human well-being.

The scenarios were developed using both quantitativemodels and qualitative analysis. For some drivers (suchas land-use change and carbon emissions) and someecosystem services (such as water withdrawals and foodproduction), quantitative projections were calculatedusing established, peer-reviewed global models. Otherdrivers were estimated qualitatively. For example,estimations were made for economic growth and rates oftechnological change, changes in the supply of ecosystemservices (particularly supporting and cultural services suchas soil formation and recreational opportunities) and forrates changes in human well-being indicators, such ashuman health and social relations. In general, thequantitative models used for these scenarios addressedincremental changes but failed to address thresholds, riskof extreme events or impacts of large, extremely costly orirreversible changes in ecosystem services. Thesephenomena were addressed qualitatively by consideringthe risks and impacts of large but unpredictable ecosystemchanges in each scenario.

The MA used these scenarios to explore the complexityand richness of the contested future. Limitations,uncertainties and flaws in the data and assumptions,together with interactions between these different inputs,mean that the precise modelling of the health impacts ofchanges in drivers are likely to remain elusive for manyyears. Nonetheless, the MA scenarios aim to use the bestavailable evidence today to assess future changes in

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ecosystem services and their relationships to human well-being, including human health (see Box 3.2).

There has been limited inclusion of health variablesin past global scenario exercises. Modelling techniquesto forecast future population health status remain in the

early stages of development. However, the models used bythe MA provide estimates for some key indicators ofhuman health, including global population and the percapita regional availability of water and food production.Many other aspects relevant to future health are restrictedto qualitative assessments.

Box 3.2 Health dimensions of the four MA scenarios

Millennium Ecosystem Assessment ScenariosThe MA developed four scenarios to exploreplausible futures for ecosystems and humanwell-being. The scenarios explored two globaldevelopment paths (globalized versusregionalized societies and economies) and twodifferent approaches for ecosystemmanagement (reactive and proactive). Inreactive management, problems are addressedonly after they become obvious, whereasproactive management attempts to maintainecosystem services for the long term. Thesescenarios were selected to explore contrastingtransitions of global society up to the year 2050. • Globalized world with reactive ecosystem

management; an emphasis on equity,economic growth, and public goods such asinfrastructure and education (also calledGlobal Orchestration);

• Regionalized world with reactive ecosystemmanagement; an emphasis on security andeconomic growth (also called Order fromStrength);

• Regionalized world with proactive ecosystemmanagement; an emphasis on localadaptations and learning (also calledAdapting Mosaic); and

• Globalized world with proactive ecosystemmanagement; and an emphasis on greentechnologies (also called TechnoGarden).

The MA scenarios were developed with a focuson conditions in 2050, although they includesome information to the end of the century.

Global OrchestrationThis scenario depicts a globally connectedsociety in which policy reforms that focus onglobal trade and economic liberalization areused to reshape economies and governance.There is an emphasis on the creation ofmarkets that allow equitable participation andprovide equitable access to goods andservices. These policies, in combination withlarge investments in global public health andthe improvement of education worldwide,generally succeed in promoting economicexpansion and lifting many people out ofpoverty into an expanding global middle class.Supranational institutions in this globalizedscenario are well-placed to deal with globalenvironmental problems such as climatechange and fisheries’ decline.

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However, there is a reactive approach toecosystem management. People generally areconfident that ecological problems can beovercome by improved policies andtechnological advances. Nonetheless,underestimation of environmental problemsincreases the risk of ecological and socialsurprises, including emerging infectiousdiseases and widespread conflict.Health improves substantially, especially indeveloping countries. Income increases inindustrial and developing countries too. Foodproduction per person improves and thepercentage of undernourished children isreduced from its current level of over 30% to20%. The absolute number of malnourishedchildren declines also. Total population growthis lowest in this scenario and the burden ofdiseases such as HIV/AIDS, malaria,tuberculosis and depression is reduced as poorpopulations gradually improve their livingstandards, benefit from better, more inclusivegovernance and see that their children havegreater opportunities. Improved vaccinedevelopment and distribution allowspopulations in this scenario to cope with thenext influenza pandemic. The impact of othernew diseases, such as SARS, is limited bypublic health measures including vaccines.Global health organizations are better fundedand regional health capacity improves,including for primary health care, laboratoriesand hospitals. Regional shortfalls in foodharvests should be managed adequately byeffective food relief programmes.

On the negative side, increased nutritionalavailability combined with an emphasis on amarket-based approach to public health islikely to raise the prevalence of obesity and typeII diabetes everywhere. The complications,particularly from diabetes occurring at anearlier age of onset and a possible increase incancer, are likely to result in a heavy burden onhealth services.

Adverse ecological surprises, such as runawayclimate change, may be of sufficient magnitudeto have serious adverse health consequencesincluding severe damage to infrastructure andeconomic conditions. Many environmentalconditions needed for good public health couldworsen. For example, microbiological waterpollution in developing countries could becomean even more important source of ill-healththan at present. Environmental contamination

with persistent pollutants and heavy metalscould increase and cause unexpectedly severeharm to health. The scenario is vulnerable toinstitutional failure, resulting in an increasedinequality of the distribution of the greaterresources predicted in this scenario.

Order from StrengthThis scenario represents a regionalized andfragmented world that is concerned withsecurity and protection, and where regionalmarkets are emphasized. Governments,businesses and citizens focus inwardly inresponse to perceived threats, including thosefrom global terrorism. There is a progressivebreakdown of global cooperation, and increasedcompartmentalization or fragmentation ofeconomic, social and security arrangements.Scientific and cultural exchange declines.Countries and policy-makers act upon their ownshort-term interests, viewing that strategy asthe best defence against economic insecurityand other forms of instability. Generally theenvironment is seen as of secondaryimportance to security and other challenges.Also there is a belief in the ability of humans torely upon technological innovations to resolveenvironmental challenges they face, or yet toemerge. The industrial world regards certainregions of the developing world as unimportantor too chaotic for prolonged and serious social,economic and policy investment.

This scenario has the lowest investment inhuman capital. Poor countries face majorobstacles in improving the health status oftheir citizens. Institutions critical to goodgovernance remain particularly weak,exacerbating health gaps. Social and politicalinstitutions are overwhelmed by powerful lobbygroups with narrow interests, particularly thepromotion of security for privileged minorities.

The death or migration of knowledge-richadults further weakens the human capitalassets of developing countries. Inequalityincreases within and between developing andindustrialized countries. In some regions thescarcity of ecosystem services reaches criticallevels, generating poverty traps and violentconflict.

Infant and maternal mortality rates remainhigh in developing countries, as does themorbidity from obstructed labour includinginfections, epilepsy and fistulas. Prevention and

cure of important diseases is neglected.Undernutrition increases regionally,exacerbating cognitive maldevelopment andepidemics. International efforts to tacklediseases of poverty weaken. Poverty andpopulation pressures in certain regions forceincreased contact between humans andnonagricultural ecosystems to obtain bushmeatand other forest goods, leading to moreoutbreaks of haemorrhagic fever and zoonoses.

New and resurgent diseases become common indeveloping countries. Few, if any, penetrate toindustrialized countries, indeed some aspectsof health improve. While the modelling resultspredict substantial global population increasein this scenario over the next 50 years, this ishighly questionable, illustrating a case wherethe constraints and assumptions built into themodels lead to implausibility.

This scenario is more likely than others toexperience only a modest increase in total

population; social, political and economicinstability in many regions contributes totemporary and fluctuating population declinesand increases. It is also possible, though of lowprobability, that a more chronic disease couldcross from a non-domesticated animal speciesinto humans. As with HIV, this could colonizehuman populations slowly and then morerapidly, including those in industrializedcountries. The higher emphasis on security inthis scenario causes a high opportunity cost tohealth research. The higher risk of terrorismincreases anxiety for people with largerincomes.

TechnoGardenTechnology and market-oriented institutionalreform are used to achieve solutions toenvironmental problems in this scenario.Ecological engineering substitutes for, andrepairs, many ecosystem services, decoupling

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improved human well-being from ecosystemservice loss. These changes co-develop with theexpansion of property rights to ecosystemservices, such as requiring people to pay forpollution they create or paying people forproviding key ecosystem services throughactions such as preservation of key watersheds.Interest in maintaining, and even increasing,the economic value of these property rights,combined with an interest in learning andinformation, leads to a flowering of ecologicalengineering approaches for managingecosystem services.

Technological improvements in the developmentof alternative energy sources facilitate greateravailability of energy at relatively low prices.Cost-effective seawater desalinization makespossible the broader irrigation of deserts thatcurrently are sparsely populated and higher cropyields, improving food production capacity.Global nutrition improves substantially, drivingvirtuous cycles of consequent social and

economic improvements, especially among poortropical populations. Medical breakthroughsextend life expectancy and improve the qualityof the later years of life. Technological, surgical,genetic, pharmacological, nutraceutical andother scientific advances increase humancarrying-capacity on a global scale. Heat-stable, single-dose oral vaccines that conferlifetime immunity to multiple diseases aredeveloped. Water pollution and indoor airpollution are eliminated almost entirely.Societies could use new technologies for greaterexpression, strengthening social, family andhuman capital.

This utopian scenario could unravel, however, ifinstitutional improvements fail to match thepace of technological advance. In that event,public health could be undermined in manyregions and many forms of inequality could

increase, even in a scenario yielding anabsolute increase in the production ofecosystem services. Virtual reality could bemisused to pacify and condition people in waysthat reduce freedom. Devastating engineereddiseases could be released accidentally ordeliberately. Cheap robots could reduce danger,drudgery and servitude but also increaseunemployment and human exploitation. Familyand social ties could loosen if children bond tovirtual nurses rather than flesh-and-bloodplaymates. Audiences desensitized by excessivediets of virtual violence and pornography couldchallenge civil society norms if whettedappetites demand ever-increasing doses.

Increased calorie-dense food could exacerbatethe global epidemic of obesity and diabetes.Technology could narrow dietary diversity,including of micronutrients. Excessivelysedentary lifestyles in childhood could reducethe use of large muscles leading to poorlydeveloped gross motor coordination. In laterlife, increasingly sedentary behaviour couldexacerbate health conditions associated withphysical inactivity, thus cancelling out othermedical advances improving the health of theelderly. Designer drugs could prove moredangerous and addictive than promised.Discrimination based on genetic profiles foremployment and insurance could becomeroutine. Diseases targeting specific geneticcharacteristics could be engineered for ethniccleansing or other forms of genocide. Newdiseases could also arise or be more widelydisseminated by new technologies, as occurredwith several infectious diseases in thetwentieth century.

Adapting MosaicIn this scenario there is a strong emphasis onlearning about socioecological systems throughadaptive management. This focus is linked withbalancing human, manufactured and naturalcapital. Confidence in the ability of humans tobetter manage socioecological systems isbalanced by humility and an active preparationfor ecological surprises. Political and economicpower devolves to regions, with great regionalvariation, and 'learning while managing' iswidely acclaimed as an approach to goodgovernance, management and problem-solving.

However, eventually the focus on localgovernance leads to failures in managing the

global commons. Problems such as climatechange, marine fisheries’ collapse and pollutionworsen, leading to increased globalenvironmental surprises. Slowly communitiesrealize that addressing certain issues requiresan approach to management on a broaderscale. This evolves through the development ofcommunity networks focused on ecologicalunits rather than existing political borders thatdo not necessarily match ecosystemboundaries.

This scenario is thus characterized by greaterregional pride and more cultural and socialdiversity. Mental health improves, includingthat of minority populations, reducingalcoholism, domestic violence, depression andintravenous drug use. Knowledge and practiceof traditional health systems is preserved betterin this scenario. The revival of traditionalhealth systems could assist thecommercialization of new pharmaceuticals.

Food supplies per capita decline, especially insub-Saharan Africa and south Asia, but this ispartly compensated for by a more equaldistribution. Globally, the number (but notpercentage) of calorie-malnourished children ispredicted to increase by about 6% by the year2020, but then fall.

On the negative side, the global capacity toprovide emergency relief for disasters such asfamine, epidemics or earthquakes, is likely todecline. This is important because manyregions are unlikely to develop sufficient criticalmasses of expertise or economies of scale tofoster the new technologies needed to maintainhigh living standards. This could lead toregional setbacks and new poverty traps.

A dearth of global leadership could delay orundermine the establishment of effective globalenvironmental treaties. Climate change andother large-scale environmental problemstherefore may be comparatively severe in thisscenario, exacerbating their long-term adversehealth effects. The degree to which ideas,technology and capital circulate internationallyis crucial to health improvement. Without thetransfer of regional and global expertise, areasthat are disadvantaged now are likely not onlyto persist but also may become moredisadvantaged.

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3.1 Critical drivers and other factorsaffecting future changes to health

The MA defines a driver as any natural or human-induced factor that indirectly or directly causes a changein an ecosystem (S7). A direct driver is one thatunequivocally influences ecosystem processes. Importantdirect drivers include changes in climate, plant nutrient use,land-use management and change, diseases and invasivespecies. An indirect driver operates diffusely, by altering oneor more direct drivers. Examples of indirect drivers includedemographic, economic, sociopolitical, scientific,technological, cultural, lifestyle and religious factors.

Growing populations and growing economies areassociated with higher consumption and increasedpressure on ecosystems (SWG). The degree of pressuredepends on human and ecosystem factors. Human factorsinclude: demographics, technology, behaviour, policy andculture. But pressure also depends critically on theresilience of the ecosystem in question. In some cases,conservation measures may reduce the human pressure onecosystems considered to be nearing a critical threshold.In other cases, a small incremental increase in pressuremay result in an unexpected, non-linear adverse ecosystemresponse, such as the collapse of a marine fishery or acoral reef ecosystem.

3.1.1 Direct driversThe direct drivers of change vary by location. Majorcurrent and projected drivers include changes in climate,land use, nutrient loading, invasive species, fishing,modification of rivers, water withdrawal and pollution(SWG). During the first half of the 21st century, the MAscenarios indicate that the array of both indirect and directdrivers affecting ecosystems and their services will remainlargely the same as over the past half-century. However, therelative importance of different drivers will begin to shiftand change. For instance, while the rate of globalpopulation growth is projected to decline gradually as globalpopulation peaks, shifts in demographic distribution willbecome relatively more important as a driver. By the end ofthe century, climate change and its impacts may be one ofthe most important direct drivers of change for ecosystemsand their services.

3.1.2 Indirect driversWorld population probably will peak before the end ofthe 21st century at fewer than 10 billion people (S7).The global population growth rate peaked at 2.1% per yearin the late 1960s and fell to 1.35% per year by 2000 whenthe global population reached 6 billion. Population growthover the next several decades is expected to be concentratedin the poorest urban communities in sub-Saharan Africa,south Asia, and the Middle East. Populations in all parts ofthe world are expected to age during the next century.While industrialized countries will have the oldest averagepopulations, the rate of ageing could be extremely fast insome developing countries.

In the 200 years for which we have reliable data overallgrowth of consumption has outpaced increased efficienciesin production processes, leading to absolute increases inglobal consumption of materials and energy (S7). Thismeans that in practice, economic growth tends to increaseconsumption of energy and materials.

In the MA scenarios, the range of per capita incomegrowth is 200–400% between 2000 and 2050 (S7).Increasing per capita income is thus anticipated further tointensify per capita consumption in most parts of the world.Implicit in this prediction is the assumption that the linkedsocioecological system can provide sufficient human andecosystem services to feed and otherwise provide for thislarger and wealthier population. However, without majorchanges in technology, culture, or both, the pressure onecosystems seems likely to increase, as a result. For example,as incomes rise, diets tend to become higher in protein.

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3.2 Plausible future changes in ecosystemsand the health effects in different sectorsand regions

Rapid conversion of ecosystems is projected tocontinue under all MA scenarios in the first half ofthe 21st century (S9.ES). Rates of conversion ofecosystems are highly dependent on future developmentscenarios and in particular on changes in population,wealth and technology. The most land-conservingscenarios are those that include increasingly efficientagricultural production, lower meat consumption andlower population increases.

Under all four MA scenarios, the projected changes indrivers result in significant growth in consumption ofecosystem services, continued loss of biodiversity andfurther degradation of some ecosystem services (SWG).

During the next 50 years, demand for food is projectedto grow by 70–80% and demand for water by30–85%. Water withdrawals in developing countriesare projected to increase significantly under allscenarios, although they are projected to decline inOECD countries. Food security is not achieved by 2050; childmalnutrition will be difficult to eradicate.Habitat loss and other ecosystem changes are projectedto lead to a global decline in local diversity of nativespecies by 2050.

A severe deterioration of the services provided byfreshwater resources (such as aquatic habitat, fishproduction and water supply for households, industryand agriculture) is found in the scenarios that arereactive to environmental problems. Less severe butstill important declines are expected in the scenariosthat are more proactive in addressing environmentalproblems.

The scenarios identify certain 'hot spot' regions ofparticularly rapid decline in per capita ecosystemservices, including sub-Saharan Africa, the Middle Eastand south Asia (S9). Water withdrawal is likely to expandrapidly in sub-Saharan Africa, requiring an unprecedentedinvestment in new water infrastructure. Under somescenarios, this rapid increase in withdrawals will cause asimilarly quick increase in untreated return flows tofreshwater systems, which could endanger public health andaquatic ecosystems. This region could experience not onlyaccelerating intensification of agriculture but also furtherexpansion of agricultural land onto natural land. Furtherintensification could lead to a higher level of contaminationof surface and groundwater. In south Asia the pressure onecosystems could lead to sociopolitical breakdowns thatinterfere with the well-being of the population and itsfurther economic development.

Desertification, or land degradation in drylandecosystems, is projected to pose a particularlysignificant threat to human development (C22). Landdegradation refers to the loss of primary production, oftenthrough soil erosion but also through changes invegetation and through processes such as salinization andshifting sand. Approximately 10–20% of drylands sufferfrom one or more forms of land degradation (mediumcertainty). The combination of low current levels ofhuman well-being (high rates of poverty, low per capitaGDP, high infant mortality rates); a large and growingrural population; the high variability of environmentalconditions in dryland regions; and the high sensitivity oflocal populations to changes in ecosystem services; meansthat continuing land degradation could have profoundlynegative impacts on the well-being of a large number ofpeople.

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The MA scenarios found thatdryland ecosystem services areparticularly vulnerable tosubstantial and persistentreductions in ecosystem servicesdriven by climate change, waterstress and intensive use (S.SDM).Many of the most vulnerabledrylands are found in sub-SaharanAfrica and central Asia. Subsidies offood and water for people invulnerable drylands can have theunintended effect of increasing therisk of even larger breakdowns ofecosystem services in future years.Local adaptation and conservationpractices can mitigate some losses ofdryland ecosystem services,although it will be difficult toreverse trends towards loss of food production capacity,water supplies and biodiversity in drylands.

The per capita supply of food is projected to increaseunder all four scenarios, and diets in developingcountries will become more diversified (S.SDM). Foodsecurity is likely to remain out of reach of many. Childmalnutrition will be difficult to eradicate even by 2050,despite increasing food supply under all four scenariosand more diversified diets in poor countries. The Orderfrom Strength scenario leads to the highest projectednumber of malnourished children in 2050 – about 180million compared with about 170 million children today.

In the more promising scenarios related to health, thenumber of undernourished children is reduced andthe burden of epidemic diseases such as HIV/AIDS,malaria and tuberculosis also falls (S11). Improvedvaccine development and distribution could allow peopleto cope comparatively well with the next influenzapandemic, while the impact of other new diseases, such asSARS, should also be limited by well-coordinated publichealth measures.

In the Order from Strength scenario, the health andsocial conditions for rich and poor countries divergeand a negative spiral of poverty, declining health anddegraded ecosystems could develop (S11).Demographic pressures in developing countries,combined with static or deteriorating nutritional status

of local populations, could drive increased contactbetween humans and non-agricultural ecosystems, aspeople seek out bushmeat and other forest goods. Thiscould lead to more outbreaks of haemorrhagic fever andzoonoses. Sleeping sickness could increase, as povertyforces humans to penetrate tsetse fly–infested regions.New diseases could emerge from the interaction ofmultiple factors, as in the case of the Nipah virus (see Box 1.1).

The loss or depletion of certain ecosystem services canbe accommodated through substitutes. However,under the MA scenarios, an increasing number ofpeople may be unable to replace satisfactorily, orescape from, the effects of depleted ecosystem services(S11). It is possible to substitute some depleted ecosystemservices with human services and improved technology. Inmany other cases, however, exploitation of ecosystemservices of another type or in another locale is merelyintensified. Impacts often fall on the more vulnerablehuman populations globally. For instance, ecosystemimpacts of the consumer demand for wood in developedcountries may drive deforestation in poorer tropicalregions. In other cases, the sustainability of servicesavailable to future generations may be at risk (e.g. in thecase of deep-sea fisheries). The number of people affectedby depleted ecosystem services will increase as worldpopulation grows, and as an increasing number andvariety of ecosystems approach critical limits in theirability to provide certain services.

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3.3 Possible thresholds, regime shifts orirreversible changes

The dual trends of growing exploitation of ecosystemservices and the generally declining condition of mostecosystems are unsustainable and likely to lead toirreversible changes. Having crossed a threshold,recovery is generally slow, costly and may be impossible.Thresholds may become lower as anthropogenic impactssimplify systems and reduce their intrinsic resilience tochange (C5).

Non-linear (including accelerating, abrupt andpotentially irreversible) changes have been commonlyencountered in ecosystems and their services(S.SDM). Usually, changes in ecosystems and theirservices are gradual and incremental, most are detectableand predictable - at least in principle (high certainty).However, there are many examples of non-linear andsometimes abrupt changes in ecosystems. In these casesthe ecosystem may change gradually as a result of aparticular pressure, until a critical threshold is reached, atwhich point changes occur relatively rapidly as the systemshifts to a new state. Some of these non-linear changescan be very large and have severe impacts on humanhealth. Capabilities for predicting some non-linearchanges are improving. However, for most ecosystems,while science often can warn ofthe potential risks from non-linearchanges that may result fromincreased pressures on ecosystems,it cannot predict the thresholdlevels where non-linear changeswill be encountered.

Examples of non-linear ecologicalevents include runaway climatechange, desertification, fisheries’collapse, eutrophication andmajor disease. Adverse non-linearsocial events include severeconflict, governance failure andincreasing fundamentalism andnationalism. Multiple andinteracting adverse events couldalso occur (S11). For example,widespread food insecurity -resulting from severe climatechange, institutional failure and

increasingly damaged soils - could worsen inequality andlead to widespread conflict. Numerous other losses inecosystem services, while individually less dramatic, also arelikely to influence human health adversely. Their plausiblecumulative effect ranges from modest to immense. Thecumulative effects of these also will depend on social andecological resilience. If capacity is eroded, vulnerabilityincreases and can contribute to a vicious cycle of even moreimpacts resulting in immense damage to human health.

The vulnerability of human well-being to suddenadverse ecological and social changes and other non-linear events varies among the scenarios (S11).Scenarios are characterized by the likelihood of non-linearchanges, by the level and quality of preparedness to themand by social coping capacity. High levels of humancapital, and other forms of capital, do not alwaysguarantee preparedness and in some cases may lead tocomplacency. Likelihood, preparedness and resilienceinteract in any given scenario to determine the overallvulnerability of human well-being to non-linear events.Vulnerability to non-linear social and ecological events isgreatest in the Order from Strength scenario. Among theother scenarios, it varies according to the kind of eventand its scale, especially in the case of Adapting Mosaic.Global Orchestration is more vulnerable to ecologicalrather than social non-linear events.


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Experiment in agriculture in deserts and drylands.

n principle, two courses of action are availablewhereby disease and injury caused by ecosystem

disruption may be avoided. One avenue is the prevention,limitation, or management of environmental damage(mitigation strategies). A second course of action involvesmaking necessary changes to protect individuals andpopulations from the consequences of ecosystem change(adaptation strategies). We do not elaborate on the firstapproach because it is not unique to health and isexplored at length in each of the other MA reports. In thissection we begin by outlining ways of reducing humanvulnerability to the effects of ecosystem change. We drawattention, however, to the connections between actionstaken to reduce human vulnerability and actions that mayprotect the environment. In many instances, similaractions will indeed serve both goals. Nonetheless, wherepopulations are weighed down by very immediateproblems, such as a heavy burden of disease, it may bemuch more difficult to advance sustainable developmentand environmental management strategies that require alonger-term perspective. In this context, the MDGs offera framework for international action.

4.1 Reducing vulnerability

Two closely-related issues need to be considered tounderstand the potential negative health impacts ofecosystem change: current vulnerability states andcapacity for future adaptation (R16). In many cases,the forces that place human populations at risk (such aspoverty and high burdens of disease) also impair theircapacity to prepare for the future. The burden ofHIV/AIDS in Africa, for example, is a major impedimentto all development programmes, including those focusedon sustainable land use, ecosystem protection and povertyreduction.

Populations, subgroups and systems that cannot orwill not adapt are more vulnerable (R16). Somepopulation subgroups may not have the resilience toadapt because of a lack of material resources, relevantinformation, and public health infrastructure, as well as alack of effective governance and civil institutions.Appropriate targeting of interventions requiresunderstanding of the demographic or geographical


4. What actions are required to address the health consequences of ecosystem change?

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Many of the health consequences ofecosystem change are borne by children -through increased morbidity andmortality from diseases related to unsafewater and sanitation, indoor airpollution, as well as vector-borne diseasessuch as malaria.


subpopulations most at risk, the factors that contribute totheir vulnerability, and factors that potentially may bemodified within the context of a particular time andsetting. Individual, community and geographical factorsdetermine vulnerability.

4.2 The Millennium Development Goals

The Millennium Development Goals (MDGs) wereadopted by the United Nations General Assemblyfollowing endorsement of the Millennium Declarationby heads of state and government representatives at theUnited Nations Millennium Summit in September2000.

The MDGs aim to improve human well-being byreducing poverty, hunger, and child and maternalmortality; ensuring education for all; controlling andmanaging diseases; reducing gender disparities; ensuringsustainable development; and pursuing globalpartnerships. For each MDG, targets have been set tobe achieved by 2015 – referring to 1990 as the baseline.The goals are not comprehensive, and even if all wereachieved, this would not ensure equitable andsustainable development.

The United Nations Millennium Project establishedMillennium Task Forces to address the individual goalsand identify specific interventions for each goal. Someapproaches considered for achieving the MDGs may berelatively sparing of ecosystems; others would very likelyincur much heavier environmental costs (R19).

The ongoing degradation of ecosystem services is asignificant barrier to achieving the MDGs and theharmful consequences of this degradation couldgrow significantly worse during the first half of the21st century. The MDGs can best be met throughintegrated, synergistic strategies rather than isolatedinterventions. Particular emphasis needs to be placedon the sustainable intensification of existing cultivatedecosystems in order to satisfy growing demand for food- alongside the preservation of other importantecosystem services, e.g. water filtration andpurification. Balancing such dual objectives is a majorchallenge, particularly as many social and economicissues also need to be addressed in order to reducehunger (R19).

As part of a strategy for achieving the MDGs,improved ecosystem management needs to address acomplex set of drivers of environmental changethrough cross-sectoral policies, institutional actions,and investments at local, national, regional andglobal levels (see Box 4.1). Improved capacity for crosssectoral policy-making is required not only at locallevels, but also at global levels e.g. to address issues suchas climate change and depletion of internationalfisheries (R19).

Deforestation in Latin America.

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Learning to run a nursery for agroforestry in the dry country of South Nyanza,Kenya.

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Goal 1. Eradicate extreme poverty and hunger

Target 1: Halve, between 1990 and 2015, theproportion of people whose income is less thanUS$ 1 per day. The Millennium Declarationidentifies global poverty as the most daunting ofall global problems. A clear understanding of thecomplex and dynamic relationship betweenpoverty and the environment is required in orderto address this. Numerous interventions, manywith ecosystem implications, are possible to haltthe negative spiral of poverty and environmentaldegradation. Many of these interventions havepositive impacts for health, education and othergoals. For example, granting land or resourcetenure to poor rural people can increaseconservation incentives, capital investment inproduction and livelihood security.

Target 2: Halve, between 1990 and 2015, theproportion of people who suffer from hunger. FAOestimates that 840 million people go to bedhungry each night. Hunger is at least as much ofan economic (income) and social (equity anddistribution) issue as it is an issue related toecosystem services. Access to adequate food isparticularly important for poor rural populations.Interventions that increase agricultural yield andarea have significant implications for ecosystemservices. The MA findings illuminate manyaspects of these complex and dynamicrelationships. The way that ecosystems aremanaged has a significant impact on theavailability and price of food and thus on theachievement of this target (R19).

Goal 2. Achieve universal primary education

Target 3: Ensure that by 2015 childreneverywhere, boys and girls alike, will be able tocomplete a full course of primary schooling. Theexpansion of primary education is likely to havemany long-term positive impacts for ecosystemservices, especially by enhancing human capitaland individual and social capability. Yet bettereducation fosters increased hope, expectationsand capacity that some could view as potentiallyincreasing the short- to mid-term pressure onecosystem services by increasing the per capitaecological footprint. In the long run, however,education is likely to reduce the total size of thisfootprint. A better-educated population is likely tobe in a stronger position to protect, preserve and

restore essential ecosystem services, including byaccelerating the demographic transition incountries where fertility rates remain high orabove replacement level.

Goal 3. Promote gender equality and empowerwomen

Target 4: Eliminate gender disparity in primaryand secondary education preferably by 2005 andat all levels of education no later than 2015.Gender equity is an essential goal in itself andcritical for meeting the other MDGs. The date setfor achieving gender parity in primary andsecondary education is 2005 - 10 years beforethe other goals. Among the more than 780million adults who cannot read or write, nearlytwo thirds are women. Many poor populations areparticularly dependent on locally availableecosystem services for their health and otherelements of well-being (R19). Women and girlsare especially vulnerable. Often they lack not onlyproportionate access to already limited economicresources but also frequently beardisproportionate responsibility for providing thehuman services that partially compensate fordiminished local ecosystem services, such ascollecting water and fuelwood from often-increasing distances. Such heavy labourconstrains the ability of girls to attend schooland can sap energy and concentration even whenthey do.

Goal 4. Reduce child mortality

Target 5: Reduce by two thirds, between 1990 and2015, the under-five mortality rate. Despiteprogress in some countries reducing childmortality in children less than five years old, stillmore than 10 million children die unnecessarilyeach year, almost all in poor countries. In manycountries, infant and childhood mortality rates arefalling more slowly, in some countries rates havestagnated or are rising. Undernutrition is theunderlying cause of a substantial proportion of allchild deaths. The systematic application of anecosystems approach to the MDGs, as well assynergies from the other goals, will benefitreduction of the under-five mortality rate,including through improved nutrition of childrenand mothers (R19).

Unhygienic and unsafe environments placechildren's health at risk. The causal links

between infectious disease and ecosystems andtheir services are complex but are seen mostclearly among impoverished communities thatlack the buffers that the rich can afford (R16).Ingestion of unsafe water, inadequate water forhygiene and lack of access to sanitationcontribute to millions of children's deaths, asignificant portion from diarrhoea. Degraded andmodified ecosystems, especially those that allowconsiderable amounts of standing water, arefrequent sources of water- and vector-bornediseases (such as diarrhoeal diseases, malariaand dengue fever) to which children aresusceptible. Poor nutritional status andmicronutrient deficiencies among childrendecrease their immune and non-immune hostdefences, making many of them more vulnerableto infectious diseases.

Goal 5. Improve maternal health

Target 6: Reduce by three quarters, between 1990and 2015, the maternal mortality ratio. Maternalmortality can be reduced by increasing healthand gender equity through the provision ofknowledge about reproductive alternatives,antenatal care, nutrition and disease. Ensuringthat women have greater control over theirreproductive health, including access to familyplanning, can help reduce population growth andconsequent pressures on ecosystems.

Goal 6. Combat HIV/AIDS, malaria and otherdiseases

Target 7: Have halted by 2015, and begun toreverse, the spread of HIV/AIDS. Most of the interventions needed to addressHIV/AIDS are medical, educational and politicalrather than ecological. Reduced poverty and

Box 4.1 Ecosystem change and the MDGs and Targets

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improved gender equity will reduce livelihoodchoices, including prostitution, that increase therisk of HIV/AIDS. In some countries where theHIV/AIDS epidemic is very severe, such as parts ofsub-Saharan Africa, the disease is having adirect impact on ecosystems, such as by loweringagricultural production. HIV/AIDS also has a directimpact on the economy by cutting production,earnings and taxes, thereby eroding the resourcesneeded to deal with the epidemic (R19).

Target 8: Have halted by 2015, and begun toreverse, the incidence of malaria and other majordiseases. One billion people live in malaria-endemic areas and malaria is responsible forover a million deaths annually. Malaria alone isresponsible for 11% of the disease burden inAfrica (R12). Ecosystem change, including forest

clearance and irrigated agriculture, often isresponsible for increasing the incidence ofmalaria. Better ecosystem management, inconjunction with primary and secondaryprevention, is central to addressing this problem.Integrated vector management provides a rangeof environmental management tools within anecosystem framework, including modification ofthe environment, biological and chemicalcontrols.

Goal 7. Ensure environmental sustainability

Target 9: Integrate the principles of sustainabledevelopment into country policies andprogrammes and reverse the loss ofenvironmental resources. There is growingappreciation that the value of the humaneconomy is subsidized by innumerable ecosystemservices. As the ecological footprint of the humaneconomy grows, thresholds of ecosystem serviceloss and degradation draw inexorably nearer,

placing at risk the sustainability of human well-being and development. Preserving and restoringenvironmental integrity while reducing povertywhen the global population continues to grow isan immense challenge. Improved ecologicalvaluation methods that better account for theeconomic values of ecological goods and servicesignored by markets are an important tool formeeting this challenge.

Target 10: Halve, by 2015, the proportion ofpeople without sustainable access to safedrinking-water and basic sanitation. During the1990s, around 80 million people per year, onaverage, gained access to an improved drinking-water supply; and a similar number, to improvedsanitation. Still, in order to meet Target 10 of theMDGs, this achievement needs to be scaled up, sothat an additional 100 million people per year, onaverage, gain access to an improved drinking-water supply, and an additional 140 millionpeople per year, on average, gain access toimproved sanitation. In many regions, achievingthe targets on water and sanitation withoutparallel investments in water treatment canthreaten freshwater and coastal ecosystems andthe services they provide.

Target 11: By 2020, achieve significantimprovement in the lives of at least 100 millionslum dwellers. Urbanization is transforming theworld fundamentally. Close to 50% of the worldpopulation lives in urban areas, compared withonly 15% in 1900. Currently it is estimated thatover 900 million people live in slums, roughly onethird of the world's urban population. More than70% of the urban population in the leastdeveloped countries and sub-Saharan Africa livein slum-like conditions. This number is set toincrease to roughly 2 billion by 2020 unlesscurrent trends change substantially. Thechallenge is particularly acute in sub-SaharanAfrica, where urbanization proceeds at a very highpace. The most extreme forms of environmentaldegradation tend to be found in slums. Chronicpollution of water sources, high diseaseprevalence and deterioration of public healthconditions are common features in many of theseunplanned urban settlements. This target has alimited overall impact on rates of urbanizationand total urban demand for ecosystem services,since the targeted 100 million slum dwellersaccount for only a relatively small share of thetotal urban slum population (R1).

Goal 8. Develop a global partnership fordevelopment

Target 12: Develop further an open trading andfinancial system, including a commitment togood governance, development and povertyreduction, nationally and internationally.Globalization is a multifaceted collection ofprocesses, a central part of which is theexpansion of world trade. The MDGs aim to betterharness globalization to reduce poverty. Goal 8complements the first seven. It calls for an open,rule-based trading and financial system andincreased aid and debt relief to countriescommitted to poverty reduction. There aresignificant opportunities to integrate aid anddebt relief with innovative "debt for MDG" swaps(R19).

Targets 13-15: Address the special needs of leastdeveloped countries, landlocked and small islanddeveloping states and highly indebted poorcountries. Many landlocked, small island andhighly indebted nations lack the basic health,education and infrastructure capacities neededto gain adequate access to expanded marketsand make the most of more open trade regimes.Therefore, special terms of trade, officialdevelopment assistance and debt relief arerequired to finance new infrastructure and toaddress land and water sustainability issues.

Targets 16-18: In cooperation with developingcountries and the private sector, address youthunemployment, access to affordable essentialdrugs and access to the benefits of newtechnologies. In harnessing globalization toreduce poverty and achieve sustainabledevelopment, the implications for ecosystemsand their services must be a primaryconsideration. Recent estimates place the valueof the world's ecosystems at more than the totalvalue of the world's economy, taking into accountthe value of freshwater purification, pollination,clean air, flood control, soil stability and climateregulation (R19). Nevertheless, recognition ofecosystem services seldom penetrates policydebates. In making trade-offs between progresson human development goals and maintenanceof ecosystem services, and in order to makebetter choices possible, improved ecologicalvaluation methods need to be used to take moreaccount of the economic values of ecologicalgoods and services ignored by markets.

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5.1 What considerations are important whensetting priorities and what is science's role ininforming decisions?

riorities for actions addressing the human healthconsequences of ecosystem change should reflect

the priorities and values of those who are affected by theaction (R16). The final decisions about priorities thereforeshould be taken either by individuals or by their legitimatepolitical representatives with reference to these values. Oftendecision-makers use multiple criteria (such as equityconcerns, efficient use of scarce natural resources, politicalfeasibility and cultural considerations) to set priorities.Scientific assessments can inform these decision-makingprocesses. Assessments should strive to be policy-relevantwithout being policy-prescriptive, providing timely anduseful information that allows stakeholders to judge how anaction or inaction corresponds to their priorities.

Policy-relevant scientific assessments have led directly tomany important decisions protecting public health fromenvironmental risks. In many countries and settings,legislation regulating environmental exposures to lead,asbestos and secondary tobacco smoke, for instance, havebeen facilitated by evidence synthesized by health scientistswho measured the links between environmental exposuresand health outcomes, reached a reasonably broad consensusregarding health impacts, and presented these findings topolicy-makers. Experiences implementing the MontrealProtocol on Substances that Deplete the Ozone Layerdemonstrate that health considerations also can beimportant in decisions by local policymakers andstakeholders to address global environmental issues. Thisexperience may encourage decision-makers similarly toaddress the health aspects of other risks, such asdesertification, biodiversity loss and climate change.

5.2 How can we measure the size anddistribution of the health effects of ecosystemchange?

In the last decade, new approaches have been developedto assess the overall effects of environmental risks andother risks to population health. Where it is possible tomeasure the effect of an ecosystem alteration on the rates of

specific diseases, this can also be used to estimate the overall'burden of disease' caused by that change. This can bedescribed in terms of disability-adjusted life years (DALYs).DALYs represent the sum of years of life lost from prematuredeath (e.g. the actual age at death compared with natural lifeexpectancy) and the number of years of life lived with adisability (e.g. the duration of the disease, weighted by ameasure of its severity). These measures allow health impactsexperienced as a result of multiple causes or through multiplecausal pathways to be summed together. For example, thecombined effects of climate change on morbidity andmortality from infectious diseases, malnutrition, and theimpacts of natural disasters can be aggregated into a singleDALY measurement. Potentially this allows directcomparisons of the effects of different ecological changes (orany other risk factors) on population health and can act as aguide for rational priority-setting for an action (R16).

It is important to consider which subsections of thepopulation are most affected by ecological changes,including the distribution of disease by age, gender, socialstatus, ethnicity and geographical region. Global estimatesfor the year 2000 indicated that among the poorest countrieswith the highest mortality rates, between one-sixth and onequarter of the disease burden was attributable to childhoodand maternal undernutrition. Children and pregnant womenare at much greater risk from malaria, both in terms ofmorbidity and mortality, particularly if they are malnourished.Morbidity and mortality due to heatwaves, meanwhile, ishighest among the elderly.


5. How can priorities be established for actions toaddress the health consequences of ecosystem change?

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Burden-of-disease assessments depend on access toquantitative data sufficient to relate changes in exposureto the incidence of specific diseases. Within theenvironmental health field, such assessments have beencarried out most successfully among defined or discretepopulation groups, in relation to localized environmentalfactors characterized by a set of well-defined dose-responsehealth effects, e.g. air pollution exposures or environmentallead exposures. Such assessment is more difficult to apply inthe case of ecosystem effects acting through more diffusecausal pathways. For example, reduced availability of freshwater could affect health adversely by increasing a range ofwater-borne diseases and also by reducing agriculturalproduction. However, any quantitative projections of theseeffects are likely to have a higher degree of uncertainty thanthe examples just described. This is due to the multitude ofother important causal factors (such as weather conditionsduring growing seasons) and diverse causal pathways of theimpacts. For instance, water availability may influence notonly plant growth rates but also agricultural pests anddiseases, all of which in turn affect overall yields.

Considerations of timescale are equally important.Comparative risk assessments of the burden of diseaseattributable to climate change indicate that health impactsare modest compared with other risk factors over the brieftime frames in which many political decisions are taken (a

five-year horizon, at most). However, they becomeconsiderably more significant when impacts are consideredover several decades. They are, therefore, of greater relevancewhere far-sighted policy-makers make decisions with longtime horizons. Examples include large capital investments,such as planning decisions on the reconstruction of urbancombined sewage systems or building on flood-prone areas.These would benefit from consideration of changing risksover decades rather than years. The burden-of-diseaseframework also fails to take account of differences betweenenvironmental risk factors that could be readily addressed byrobust policies as new information becomes available abouthealth impacts (e.g. urban air pollution), and other impacts(such as biodiversity loss) which may be irreversible.

Burden-of-disease evaluation is thus an appropriate toolfor estimating and aggregating health impactsattributable to one particular ecosystem mechanism orto a range of ecosystem mechanisms. This tool potentiallycan aid priority-setting and decision-making to addressecosystem change. However, burden of disease assessmentshould be regarded as only one component of evidence assuch evaluations cannot account fully for complex causalpathways, long timescales and potential irreversibility. Theseimportant properties need to be included in finalconsiderations about any response to ecological change(R16).

Box 5.1 Interventions to reduce ecosystem change's pressures on health services - examples of promising responses

Provide technical and financial assistance to implement the GlobalStrategy for Health for All, including health information systems andintegrated databases on development hazards.Strengthen advocacy for the provision of basic preventive and curativehealth care at all levels. Review delivery of basic health services at thelocal level to ensure that priority problems of poor people are addressedadequately.Make essential drugs affordable and available to the world's poorernations including, where necessary, alterations in the multilateral tradesystem, national policies and institutional drug supply management. Implement long-range health and human resource planning to train,recruit and retain staff. Develop codes of conduct for internationalrecruitment of health professionals.Strengthen health services for displaced communities and those affectedby war, famine or environmental degradation.Implement health impact assessment of major development projects,policies and programmes and monitor indicators for health andsustainable development.

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5.3 What kinds of intervention options areavailable?

Responses to ecosystem changes include: mitigation(reducing or reversing the extent and rate of change) andadaptation (increasing systems' resilience to change - toreduce the current and future risks and take advantageof opportunities posed by those changes) (R16). Decisions on priority actions should include the bestevidence available on the likely effectiveness of anyintervention in either class. Mitigation and adaptationresponse options can include legal, economic and financial,institutional, social and behavioural, technological orcognitive measures and actions. They encompass bothspontaneous responses to ecosystem change and planned(anticipatory) interventions by affected individuals andinstitutions such as governments. Responses that protecthuman health very often involve actions outside the healthsector (see Box 5.1).

The health sector bears responsibility for informingdecision-makers about the health effects of ecosystemchanges and potential interventions. Where there are trade-offs to be made, for instance between more effective long-term mitigation and a faster rate of present-day economicgrowth, it is important for politicians, regulators and thepublic to understand the health consequences. These can beincluded alongside economic or other costs when settingpriorities. Optimally, decision-makers may assign a higherpriority to win-win options – for example, specificgreenhouse gas mitigation measures that lead not only tolong-term reductions in the risks of deaths in heatwaves,floods, droughts etc. but also bring benefits in terms offewer deaths from air pollution in the short-term.

In almost every type of policy or community response toecosystem changes, the consequences for health may beeither positive or negative (R16). The outcome will dependon how the policy or regulation is framed, and what accountis taken of contingencies and local circumstances. Forinstance, global trade and economic agreements have greatlyfacilitated the increased quantities and diversity of foodproducts available in many markets around the world, whichmay be beneficial to health. In other settings, however,globalized trade in food may have contributed to diminishedfood access and security, deepening poverty, and deterioratingstandards of public health.

Adaptation interventions need to be designed atspatial and temporal scales appropriate to the healthoutcome of concern, taking into consideration thesocial, economic and demographic driving forces(R16). They also should be targeted towards particularlyvulnerable groups that have the least capacity to adapt toecosystem change. Such targeting requires understandingof which demographic or geographical subpopulationsmay be most at risk, the factors contributing to theirvulnerability and which of these can be modified feasiblyand effectively. Some of the most important determinantsof vulnerability to any particular level of risk are the levelof material resources, effectiveness of governance and civilinstitutions, quality of public health infrastructure, accessto relevant information and existing burden of disease.These factors are not uniform across a region or nation;rather, there are geographical, demographic andsocioeconomic differences.

Cross-sectoral policies that promote ecologicallysustainable development and address underlying drivingforces also will be essential (R16). Agenda 21 and the RioDeclaration on Environment and Development describe acomprehensive approach to ecologically sustainabledevelopment incorporating cross-sectoral policies. Indefining the options that may be available through cross-sectoral policies, the following strategies are of specificrelevance to health.

Integrated action for health, making use of tools such ashealth impact assessment of major development projects,policies, programmes and indicators for health andsustainable development.


A microscopic view of the tiny crustacean Mesocyclops. CertainMesocyclops species have been identified in Viet Nam and other Asianlocales as highly efficient predators of the Aedes aegypti larvae, the mainmosquito vector of dengue fever, and are important for controlling thedisease.

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Including health in sustainable development planningefforts such as Agenda 21, multilateral trade andenvironmental agreements, and poverty reductionstrategies.Improvement of intersectoral collaboration betweendifferent tiers of government, government departmentsand NGOs.International capacity-building initiatives that assesshealth and environment linkages and use the knowledgegained to create more effective national and regionalpolicy responses to environmental threats.Dissemination of knowledge and good practice on healthgains from intersectoral policy.

5.4 How should priorities for these options beestablished?

The process for deciding priority options varies acrossjurisdictions, institutions and cultures. The MA hasidentified a series of elements that tend to improveoutcomes for ecosystems and human well-being (R18.ES)including the following.

Use of best available information with consideration ofthe full range of effects of policies, including trade-offs,across ecosystem services.Where possible, valuation of both marketed and non-marketed ecosystem services.Aim to maximize efficiency (benefit per unit investment)but not at the expense of effectiveness (overall benefit).Consideration of equity and vulnerability in terms of thedistribution of costs and benefits.

Recognition that not all values at stake can be quantified,thus quantification can provide a false objectivity indecision processes that have significant subjective elements.Provision of regular monitoring and evaluation.

Use of certain quantitative tools may support prioritysetting. In the health sector, risk assessments are conducted(e.g. using burden of disease tools) to estimate the directhealth gains that could be obtained from alleviating aparticular risk factor. Cost-effectiveness analysis (CEA) maybe used to assess the health benefits of policy optionsdirectly against financial costs in order to select options thatmaximize health efficiency.

However, many policies have effects across multipleecosystem services, often with long-term, diffuse anduncertain effects on both health and non-health aspects ofwell-being. In these cases decision-making may be supportedbetter by a combination of techniques, including cost-benefit analysis (which value diverse benefits in the sameunits, usually monetary); analysis of the distribution of costsand benefits across different socioeconomic groups; andqualitative considerations of the precautionary principle.

Once a decision to intervene has been made, cost-effectiveness criteria also can be used to select a preferredintervention among various alternatives (R16).Increasingly, approaches such as CEA are used to setpriorities among interventions that will bring similar healthgains - when the main factor that distinguishes between theinterventions is their cost. Policy-makers can use cost-effectiveness ratios (e.g. dollars per DALY) of the variousoptions to select those that provide the greatest health gainsfor any specified level of resources. Thus, CEA can be usefulto compare similar kinds of policies whose effects are limitedmainly to the health sector and are comparable in terms ofdeaths or DALYs. An analysis of cost-effectiveness acrossdifferent socioeconomic groups can be conducted in orderto gain more information about how interventions are likelyto benefit particularly vulnerable groups in the population.

Examining a cup of water for Aedes aegypti larvae in a community in north VietNam. This is a simple way to examine the effectiveness of interventions. Large-scaletrials in the region involving the introduction of Mesocyclops into water tanksand containers have eliminated dengue in a number of locales. This is an exampleof improved environmental management of vector-borne disease yielding healthbenefits and also helping to minimize the impacts on ecosystems from excessive useof chemically-based vector control tools.

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5.5 How can stakeholders and policy-makersbe involved?

In order to affect either official policy or individualbehaviour, it is necessary to take account of how risk isperceived among vulnerable communities. Effective riskcommunication strategies maximize the chances that policyinterventions will enjoy popular support, and thus besuccessfully implemented. .

Vulnerable communities that are most likely to beaffected by ecological changes should be involvedthroughout the entire policy-focused assessmentprocess, not as an afterthought. Communityengagement in the process provides access to localknowledge about the effects of ecological factors, ensuresthat the assessment addresses the issues of greatest concernto those affected, and maximizes the probability that anyrecommended change in policy or behaviour will beadopted. If a source of information is not widely trusted,it is unlikely that recommended changes will be accepted.

Community surveys have shown that some groups tend tobe regarded as highly trustworthy; others (such asgovernment agencies) are treated with caution. Healthcare providers tend to be regarded as one of the high-trustgroups, underlining again their important role inexplaining the significance of healthy ecosystems.

Consultation should make the best use of the expertiseof both stakeholders and researchers. Engagement of allrelevant groups will also result in credible research withrapid translation into practice. Stakeholders may haveexpert local knowledge but inaccurate ideas of the truenature of risks associated with different factors; researchersshould have more exact knowledge of disease processesand relative risks but may estimate inappropriately howgeneral concepts apply to local situations. Accurate andaccessible reporting of assessment results can remedyinaccurate risk perceptions and enhance the public'sability to evaluate science and policy issues. In many pastpolicy experiences, poor reporting misled anddisempowered a public that is affected increasingly by

applications of science and technology.

Emotive and economically importantissues such as global environmentalchange present additional challengesto risk communication and tounderstanding risk perception. It isimportant to avoid overrepresentation ofthe views of a minority of thepopulation who may emphasize onlyone aspect of an issue (special interestgroups, for instance, may focus only onthe need to conserve ecosystems withoutreflecting wider societal interests inenhancing economic growth too). Suchgroups can include industries thatperceive action to protect theenvironment to be harmful to business.They may have significant resources topromote assessments of risks or publicperceptions that are consistent with theirown financial interests, not necessarilythe interests of the wider population.


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5.6 How does uncertainty affect priority-setting?

There are unavoidable uncertainties about the impacts ofglobal environmental changes on public health. Theseinclude the potential magnitude, timing and effects of globalenvironmental change; sensitivity of health to changes inecosystem services; effectiveness of different courses of actionin addressing potential impacts; and the shape of futuresocieties (e.g. changes in socioeconomic and technologicalfactors, and associated disease burdens). Traditionalepidemiological methods are not well-suited to such issues asthey are designed to test the influence of discrete risk factorson well-defined health outcomes (such as smoking's effect onlung cancer) and to emphasize avoidance of an incorrectidentification of a harmful effect. In contrast, globalenvironmental change has diverse and wide-ranging ratherthan discrete effects on individuals or small areas and anabsence of control groups. It may be difficult or impossibleto reverse, so false negative effects are equally as important asfalse positives. However, new epidemiological methods arebeing developed to predict the emerging health impacts ofenvironmental change.

The level of uncertainties and the unsuitability ofstandard approaches lead many scientists to avoidattempting to answer some questions posed directly bydecision-makers. For example, a policy-maker may askwhether a particular mitigation strategy is likely to lead tooverall benefits or harm to health. Scientists tend to respondwith a scientifically more rigorous and less uncertain answerto a small part of the equation (such as a demonstration thatclimate variations cause increases or decreases in diseasevector abundance in a specific location).

It is important that scientific assessments attempt to givedirect answers to decision-makers' questions, even if theycan be only very approximate. However, it is essential thatany such assessments be accompanied by an accurate andunderstandable description of underlying assumptions,associated uncertainties and the implications of theuncertainties for the potential outcomes of decisions beingmade. Sometimes it is argued that the existence of theseuncertainties precludes policy-makers from taking action tomitigate and adapt to global environmental change. This ismisleading, since decision-makers (from politicians toindividual citizens) make many decisions with uncertainoutcomes every day. An informed decision is better than anuninformed one. Uncertainties attached to potentially largeand irreversible risks strengthen rather than weaken the casefor precautionary action.

Scientific assessments can provide decision-makers with arange of information on how actions to deal with globalenvironmental change may address their concerns. Theseinclude, for example, identifying interventions that provide thegreatest health protection for the lowest costs and thatcorrespond to their values, such as fairness and equity. It mayappear that by providing several different approaches topriority-setting and failing to recommend specific courses ofaction, the scientific community is providing a poor service.This is not the case. By presenting different kinds ofapproaches, assessments can be "policy-relevant, but notpolicy-prescriptive"- helping to clarify the current state ofknowledge in relation to decision-makers' values but leavingthem with the final decision on whether and how to act.Scientists fail in their responsibilities when they describecurrent scientific understanding of issues in a manner that doesnot relate to decision-makers' concerns; provides informationbiased towards particular subgroups or special interests; orhides uncertainties in an assessment of an action or inaction.


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Indigenous residents of an Indonesian forest region use a Global Positioning System(GPS) to map boundaries, prevent illegal logging and thus protect vital ecosystemservices upon which they depend.


robust finding is defined as one that holds under avariety of approaches, methods, models and

assumptions and that is expected to be relativelyunaffected by uncertainties. In this context, addressingkey uncertainties regarding ecosystem change andhuman health, potentially may lead to new and robustfindings in relation to the questions addressed in thisreport, or may provide greater accuracy regardingquantification of the magnitude or timing of costs,benefits, ecosystem changes, impacts on human well-being or on responses.

6.1 Policy implications of the most robustfindings

Ecosystem services are indispensable to the well-being of people everywhere. Local conditions exert avery strong influence on the nature, extent and timingof the effects of a particular ecosystem disruption onhealth. In general, the links between ecosystem changeand human health are seen most clearly amongimpoverished communities. These lack the buffers thatthe rich can afford and often are most directlydependent on productive ecosystems for their health(R16).

Changes in ecosystems have a more direct influenceon human well-being among poor populations thanamong wealthy populations. Social adaptations may minimize, displace orpostpone the health effects of ecosystem disruption,but there are limits to what can be achieved.Even wealthy populations cannot be insulated fullyfrom the degradation of ecosystem services. Policies and actions to reduce vulnerability need tobe comprehensive and sensitive to broader drivingforces and issues of scale but at the same timeaccount for differences between settings and locales. Broad frameworks should not be taken automaticallyas reliable guides to local conditions.

Major inequalities exist in the access to ecosystemservices (R16). Historically, poor people have lostaccess to ecosystem services disproportionately asdemand for those services has grown. Where apopulation is weighed down by disease related topoverty, and lack of entitlement to essential resourcessuch as shelter, nutritious food or clean water, theprovision of these resources should be the first priorityfor public health policy. Such changes could improvehealth in the short term and contribute to long-termecological sustainability.

Growing populations and growing economies areassociated with higher consumption; this increasespressures on ecosystems. At the same time, wealthiersocieties have a greater capacity to protect ecosystemsand the services they provide. Therefore, the degree ofpressure depends on technologies, behaviours, policies,social systems and other factors. Economic growthtends to increase consumption of energy and materials.Efficiency gains and shifts of consumption patternsfrom goods to services tend to reduce energy andmaterials’ consumption intensity (per unit of output).Nonetheless, such savings have been outpaced by theoverall global demand for, and consumption of, energyand materials so that absolute consumption ofecosystem services continues to grow.

6. What are the policy implications of the most robust findings and key uncertainties?

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Where ill-health is directly or indirectly a result ofexcessive consumption of ecosystem services (such asfood and energy), substantial reductions inconsumption would have major health benefits andsimultaneously reduce pressure on life-supportsystems.Introducing less-polluting transportation systems andreducing vehicle dependence could lead to fewerinjuries, more physical activity among sedentarypopulations and reductions in local air pollution andgreenhouse gas emissions.Integration of national agricultural and food securitypolicies with the economic, social and environmentalgoals of sustainable development could be achieved,in part, by ensuring that the environmental andsocial costs of production and consumption arereflected more fully in the price of food and water.In rich countries, reduced consumption of animalproducts and refined carbohydrates would havebenefits for both human health and ecosystems.

Measures to ensure ecological sustainability couldsafeguard ecosystem services and therefore benefithealth in the long term (R16). A healthy communityis more capable of sustaining local ecosystems, soinequalities in access to ecosystem services couldbecome ecologically unsustainable. The goals of

ecological sustainability and human health are mutuallyreinforcing. Choices made about the management ofecosystems can have important consequences for health,and vice versa. Consideration of ecosystem changeenlarges the scope of health responses by highlighting'upstream' causes of disease, injury and prematuredeath. Consideration of social determinants ofecosystem change enlarges the scope of ecosystemmanagement. The health sector can make an importantcontribution to reducing the damage caused byenvironmental disruptions, but the greatest gains wouldbe made by interventions that are partly or whollyplaced in other sectors.

To achieve the goal of enhancing human well-beingwhile conserving ecosystems, wide-ranging reformsof governance, institutions, laws and policies arerequired. Effective management cannot focus on asingle approach (markets, local control, governmentcontrol etc.). Response strategies must be tailored to thespecific social and environmental context. Effectivemanagement of the ecosystems in any particular regioncannot be achieved through a narrow focus on responsesat any one scale (local, national, regional or global).International agreements are indispensable foraddressing ecosystem-related concerns but they tend towork most effectively when focused on narrowlydefined issues.

Market mechanisms do not automatically addresspoverty and equity goals. Intervention strategies willbe more effective in reducing poverty when they respectdifferent degrees, and types of use, of ecosystem servicesby different communities. Poverty reduction strategiesmust take into account the important role ecosystemscan play to improve the health and well-being of theworld's poorest. Markets can be modified to ensure thatpoverty and equity goals are met but still use scarceenvironmental and natural resources efficiently to meetthose goals. For example, the benefits of reducingeffluent emissions into fresh water can be internalizedby imposing emissions taxes on the polluters.

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6.2 Policy implications of key uncertainties

A cascade of uncertainties is associated with legal,market, institutional and behavioural responses.Integration across response strategies can mitigate andreduce elements of uncertainty but it is unlikely that itcan be eliminated in any important context. Maincurrent uncertainties include:

a limited ability to quantify and predict the actualrelationships between biodiversity changes andchanges in ecosystem services for particular placesand times (C29);the absence of quantitative models linking ecosystemchange to many ecosystem services (S13);limited information on the details of linkagesbetween human well-being and the provision ofecosystem services, except in the case of food andwater (C29); andlimited information on the economic consequencesof changes in ecosystem services at any scale.

Can society achieve a "sustainability transition" inwhich human well-being is improved without criticaldegradation of ecosystems and their goods andservices? Ingenuity, technological progress and socialreorganization are facilitating decreased energy andmaterial intensity per unit of economic output. This,together with the possibility of increased ecosystemservice intensity and substitution, suggests that pressureon ecosystem services can one day be decoupled fromequitable growth in human well-being. In the nearfuture, however, humankind's ecological 'footprint'inevitably will expand further due to populationgrowth, poverty reduction goals and the parallelexpansion of affluence and consumption.

Unavoidable uncertainties about the impacts ofglobal environmental changes on public healthshould not be an excuse for delaying policydecisions. A precautionary approach to policy-makingmay be most appropriate, given the potential for seriousand irreversible adverse human health impacts ofecological degradation.


APPENDIX A Abbreviations, Acronyms and Figure Sources

BSE bovine spongiform encephalopathyCBD Convention on Biological DiversityCEA cost-effectiveness analysisCO2 carbon dioxideDALY disability-adjusted life yearFAO Food and Agriculture Organization of the United NationsGDP gross domestic productMA Millennium Ecosystem AssessmentMDG Millennium Development GoalNGO nongovernmental organizationOECD Organisation for Economic Co-operation and DevelopmentPCBs polychlorinated biphenylsSARS severe acute respiratory syndromeUNCCD United Nations Convention to Combat Desertification

Figure sources

Several figures used in this report were redrawn from figures included in the technical assessment reports in the chaptersreferenced in the figure captions. Preparation of several figures involved additional information as follows:

Figure SDM 1 – Harmful effects of ecosystem change on human health. The figure represents a synthesis of information onecosystem health links from throughout the MA; most importantly from C14, R12, R16 and S11.

Figure 1.4 – Access to improved water and sanitation facilities globally. The source figures (C7 Fig 7.13 and 7.14) arebased on World Health Organization and United Nations Children’s Fund, Global Water Supply and SanitationAssessment 2000 Report, Geneva, World Health Organization – updated for 2002 using the WHO online database.

Figure 1.5 – Child mortality. The figure is based on the most recent child mortality statistics reported in the WorldHealth Report 2005, Make every mother and child count, Geneva, World Health Organization, 2005.

Figure 1.6 – Percentage of households using solid fuel for cooking. The figure is based on data cited in R16, originally reported inthe World Health Report 2002, Reducing risks, promoting healthy life, Geneva, World Health Organization, 2002.


Note that text references to CF, CWG, SWG, RWG, or

SGWG refer to the entire working group report. ES refers

to the Main Messages in a chapter.

Ecosystems and Human Well-being: A Framework for

Assessment

CF.1 Introduction and Conceptual

Framework

CF.2 Ecosystems and Their Services

CF.3 Ecosystems and Human Well-being

CF.4 Drivers of Change in Ecosystems and Their

Services

CF.5 Dealing with Scale

CF.6 Concepts of Ecosystem Value and Valuation

Approaches

CF.7 Analytical Approaches

CF.8 Strategic Interventions, Response Options, and

Decision-making

Current State and Trends: Findings of the Condition

and Trends Working Group

C.SDM Summary

C.01 MA Conceptual Framework

C.02 Analytical Approaches for Assessing Ecosystem

Conditions and Human Well-being

C.03 Drivers of Change (note: this is a synopsis of

Scenarios Chapter 7)

C.04 Biodiversity

C.05 Ecosystem Conditions and Human Well-being

C.06 Vulnerable Peoples and Places

C.07 Fresh Water

C.08 Food

C.09 Timber, Fuel, and Fiber

C.10 New Products and Industries from Biodiversity

C.11 Biological Regulation of Ecosystem Services

C.12 Nutrient Cycling

C.13 Climate and Air Quality

C.14 Human Health: Ecosystem Regulation of

Infectious Diseases

C.15 Waste Processing and Detoxification

C.16 Regulation of Natural Hazards: Floods and Fires

C.17 Cultural and Amenity Services

C.18 Marine Fisheries Systems

C.19 Coastal Systems

C.20 Inland Water Systems

C.21 Forest and Woodland Systems

C.22 Dryland Systems

C.23 Island Systems

C.24 Mountain Systems

C.25 Polar Systems

C.26 Cultivated Systems

C.27 Urban Systems

C.28 Synthesis

Scenarios: Findings of the Scenarios Working Group

S.SDM Summary

S.01 MA Conceptual Framework

S.02 Global Scenarios in Historical Perspective

S.03 Ecology in Global Scenarios

S.04 State of Art in Simulating Future Changes in

Ecosystem Services

S.05 Scenarios for Ecosystem Services: Rationale and

Overview

S.06 Methodology for Developing the MA Scenarios

S.07 Drivers of Change in Ecosystem Condition and

Services

S.08 Four Scenarios

S.09 Changes in Ecosystem Services and Their

Drivers Across the Scenarios

S.10 Biodiversity Across Scenarios

APPENDIX B Assessment Report Tables of Contents


S.11 Human Well-being Across Scenarios

S.12 Interactions Among Ecosystem Services

S.13 Lessons Learned for Scenario Analysis

S.14 Policy Synthesis for Key Stakeholders

Policy Responses: Findings of the Responses Working

Group

R.SDM Summary

R.01 MA Conceptual Framework

R.02 Typology of Responses

R.03 Assessing Responses

R.04 Recognizing Uncertainties in Evaluating

Responses

R.05 Biodiversity

R.06 Food and Ecosystems

R.07 Freshwater Ecosystem Services

R.08 Wood, Fuelwood, and Non-wood Forest

Products

R.09 Nutrient Management

R.10 Waste Management, Processing, and

Detoxification

R.11 Flood and Storm Control

R.12 Ecosystems and Vector-borne Disease Control

R.13 Climate Change

R.14 Cultural Services

R.15 Integrated Responses

R.16 Consequences and Options for Human Health

R.17 Consequences of Responses on Human Well-

being and Poverty Reduction

R.18 Choosing Responses

R.19 Implications for Achieving the Millennium

Development Goals

Multiscale Assessments: Findings of the Sub-global

Assessments Working Group

SG.SDM Summary

SG.01 MA Conceptual Framework

SG.02 Overview of the MA Sub-global Assessments

SG.03 Linking Ecosystem Services and Human Well-

being

SG.04 The Multiscale Approach

SG.05 Using Multiple Knowledge Systems: Benefits

and Challenges

SG.06 Assessment Process

SG.07 Drivers of Ecosystem Change

SG.08 Condition and Trends of Ecosystem Services

and Biodiversity

SG.09 Responses to Ecosystem Change and their

Impacts on Human Well-being

SG.10 Sub-global Scenarios

SG.11 Communities, Ecosystems, and Livelihoods

SG.12 Reflections and Lessons Learned

Secretariat Support OrganizationsThe United Nations Environment Programme (UNEP) coordinates the Millennium Ecosystem

Assessment Secretariat, which is based at the following partner institutions:

Food and Agriculture Organization of the United Nations, Italy

Institute of Economic Growth, India

International Maize and Wheat Improvement Center (CIMMYT), Mexico (until 2002)

Meridian Institute, United States

National Institute for Public Health and the Environment (RIVM), Netherlands (until mid-2004)

Scientific Committee on Problems of the Environment (SCOPE), France

UNEP-World Conservation Monitoring Centre, United Kingdom

University of Pretoria, South Africa

University of Wisconsin-Madison, United States

World Resources Institute (WRI), United States

WorldFish Center, Malaysia

Maps and graphics: Emmanuelle Bournay and Philippe Rekacewicz, UNEP/GRID-Arendal, Norway

The production of maps and graphics was made possible by the generous support of the Ministry of

Foreign Affairs of Norway and UNEP/GRID-Arendal. Funding for this publication also was provided

by the Global Change Research Programme in the United States Environmental Protection Agency’s

Office of Research and Development, National Center for Environmental Assessment.

This report was prepared by the World Health Organization as a contribution to the Millennium

Ecosystem Assessment, with contributions from:

Communications coordination: Nada Osseiran

Editing and design coordination: Elaine Fletcher

Text editor: Jo Woodhead

Graphic design:

Front cover photos

Above: The dependency of half of the world's population on fuelwood for domestic cooking and

heating is a significant factor in respiratory diseases from indoor air pollution, and can contribute to

deforestation and ecosystem change. Photo credit: Nigel Bruce, University of Liverpool.

Below: Artemisia annua, the botanical source of the artemisinin compound, used in artemisinin-based

combination therapies (ACTs) to treat forms of malaria that have become resistant to other anti-mala-

rial medications. Photo credit: Scott Bauer, ARS Photo Unit, United States Department of

Agriculture (USDA).

Front inside cover photo: Market in La Paz, Bolivia. Photo credit: A. Waak/Pan American Health

Organization/World Health Organization (PAHO/WHO).

Back cover photo: Fishing in Vietnam. Photo credit: UNEP/Ta Hai/TopFoto.co.uk.

Photo (this page): Ethiopia; Collecting water. Photo credit: M. Marzot, Food and Agriculture

Organization (FAO)/17067.

ISBN 92 4 156309

Documents

ECOSYSTEMS AND HUMAN WELL BEING and human well... · 2008. 9. 11. · Achim Steiner, Director General, IUCN - The World Conservation Union Halldor Thorgeirsson, Coordinator, United