CLIM 101 // Global Warming, Weather, Climate and Society // Fall 2012 Impacts of Climate Change Impacts on Natural Systems Impacts on Society: Impacts

CLIM 101 // Global Warming, Weather, Climate and Society // Fall 2012

Impacts of Climate Change

Impacts on Natural SystemsImpacts on Society: water, agriculture, food, and human health

CLIM 101: Global Warming: Weather, Climate and Society


HumansEcosystems

WeatherClimate


From AVISO.oceanobs.com

Global Sea Level


Reconstructed fields since 1870Coastal tide gaugesSatellite altimetry

base period

Sea level rise in mm from 1860 onward based on a merging of three different datasets.

Sea Level Rise over the Last 150 Years

0.17 m (7.5”) since 1900


• Cryosphere– Consists of: snow, river and lake ice, sea ice, ice shelves and ice

sheets, glaciers and ice caps, frozen ground– 2nd largest component of the climate system (75% of fresh water)– Linked to energy budget (reflection of solar radiation)– Natural sensor of climate variability (“canary in the mine”)– Important climate change variable

• Snow cover• Polar Sea ice – Arctic and Antarctic• Continental Ice Sheet – Greenland and Antarctic• Mountain Glaciers – Tropics and mid-latitude• Permafrost (Frozen Ground)

Changes in Cryosphere


Sea Ice


Arctic Sea Ice is Disappearing

2007: 38% below average2008: 34% below average


7Mar2011

15Sep2011


Arctic Sea Ice


Greenland Ice Sheet MeltNearly 2 Trillion Tons of Ice Melt since 2003

(Enough to fill 20 Chesapeake Bays) Melting Greenland ice sheet would raise global sea level by 7 m.


Based on GRACE data


Northern HemisphereFrozen Ground

Seasonally Frozen GroundIntermittently Frozen Ground

Permafrost (Frozen Ground)


Changes in Cryosphere

• Snow decrease

• Lake and river ice: Later formation and earlier

melt

• Sea ice extent decrease

• Loss of glaciers and ice sheets

• Sea level rise

• Permafrost loss


IPCC AR4 WG-II Report

• Chapter 3 - Fresh Water• Chapter 5 - Food • Chapter 8 - Impacts on human health

http://www.ipcc.ch/ipccreports/ar4-wg2.htm


Center of Ocean-Land-Atmosphere studies

South Asian Adaptation

Monsoon Drought in 2009


Monsoon Drought in 2009

Extreme Pakistan Floods in 2010







Impacts on Human Health• Climate change contributes to the global burden of disease and premature deaths• Climate change has:

– altered the distribution of some infectious disease vectors– altered the seasonal distribution of some allergenic pollen species – increased heatwave-related deaths

• Projected trends will: – increase malnutrition, inhibit child growth and development– increase deaths, incidence of disease and injury from heat waves, floods, storms,

fires and droughts – continue to change the range of some infectious disease vectors– have mixed effects on malaria; in some places the geographical range will contract,

elsewhere the geographical range will expand and the transmission season may be changed

– increase the burden of diarrheal diseases– increase cardio-respiratory morbidity and mortality associated with ground-level O3

– increase the number of people at risk of dengue – decrease deaths from cold

• Adaptive capacity needs to be improved everywhere• Adverse health impacts will be greatest in low-income countries. Those at greater risk

include, in all countries, the urban poor, the elderly and children, traditional societies, subsistence farmers, and coastal populations

CLIM 101 // Global Warming, Weather, Climate and Society // Fall 2012Stern Review



• Temperature dependence of malaria vector well known to researchers in the 1920s (e.g., A. Macdonald, Journal of the Royal Army Medical Corps)

• Maximum altitude and latitudinal range strongly determined by mean temperature

• Interactions between pathogen, vector, host, and climate are complex and not fully understood

• Weaker links between disease incidence and climate within endemic regions

• Vectors are subject to significant control measures in developed world, confounding link to climate.

Climate and Malaria


Cholera• Cholera

– Pathogen (vibrio cholerae) inhabits aquatic environments

– Fecal-oral transmission– Ingestion of contaminated water– Numerous pandemics throughout

history• Symptoms: diarrhea, vomiting,

nausea• Death through dehydration, loss of

electrolytes• Treatable

• Bangladesh– Endemic center of cholera– Low-lying– Densely populated– Delta of two major rivers


What is Lyme disease?• Multisystem disease in humans (and animals) caused by

a spirochaete bacterium Borrelia burgdorferi

• Non-fatal but chronic and debilitating if not treated early

• Difficult to diagnose by doctors (clinical presentation and serology)

• ~ 20,000 cases a year in USA despite high level of awareness by the public & medical practitioners

• Infects wildlife (rodents, birds, mustelids NOT deer); transmitted from one animal to another by ticks

• Ticks are not very choosy about who they bite and bite people by accident

• The geographic range of Lyme disease is tied to that of its tick vectors



Impact of Climate Change on Lyme Disease in Canada

• A northward expansion of the range of Ixodes scapularis, associated with climate change, is likely because:– Tick survival increases dramatically

– Ticks are being carried into Canada each year on migratory birds

– The habitat in many areas is suitable for tick survival

• Chaotic weather (heavy rainfall and droughts) may inhibit spread

• Spread into central Provinces may be limited by low rainfall


Fresh Water Resources and their Management

• The impacts of climate change on freshwater systems and their management are mainly due to the observed and projected increases in temperature, sea level and precipitation variability.

• Semi-arid and arid areas are particularly exposed to the impacts of climate change on freshwater.

• Higher water temperatures, increased precipitation intensity, and longer periods of low flows exacerbate many forms of water pollution, with impacts on ecosystems, human health, water system reliability and operating costs.

• Climate change affects the function and operation of existing water infrastructure as well as water management practices.

• Adaptation procedures and risk management practices for the water sector are being developed in some countries and regions (e.g., Caribbean, Canada, Australia, Netherlands, UK, USA, Germany) that have recognized projected hydrological changes with related uncertainties.

• The negative impacts of climate change on freshwater systems outweigh its benefits.


Impact of Climate Change on World Food Prices

Cereal prices versus global mean temperature change


Summary

• Projected changes in the frequency and severity of extreme climate events will have more serious consequences for food and forestry production, and food insecurity, than will changes in projected means of temperature and precipitation.

• Climate change increases the number of people at risk of hunger (high confidence). The impact of chosen socioeconomic pathways (SRES scenario) on the numbers of people at risk of hunger is significantly greater than the impact of climate change. Climate change will further shift the focus of food insecurity to sub-Saharan Africa.

• While moderate warming benefits crop and pasture yields in mid- to high-latitude regions, even slight warming decreases yields in seasonally dry and low-latitude regions.

• Experimental research on crop response to elevated CO2 confirms Third Assessment Report (TAR) findings). New Free-Air Carbon Dioxide Enrichment (FACE) results suggest lower responses for forests. Cropmodels include CO2 estimates close to the upper range of new research (high confidence), while forest models may overestimate CO2 effects.

• Globally, commercial timber productivity rises modestly with climate change in the short and medium term, with large regional variability around the global trend.

• Local extinctions of particular fish species are expected at edges of ranges.

• Food and forestry trade is projected to increase in response to climate change, with increased dependence of most developing countries on food imports.

• Simulations suggest rising relative benefits of adaptation with low to moderate warming, although adaptation may stress water and environmental resources as warming increases.


Consequences of Global Warming


SRES Scenarios – Basis for IPCC AR4


What is in store for the future and what has already been committed

Global warming will increase if GHGs concentration increase. Even if GHGs were kept constant at current levels, there is a “commitment” of 0.6°C of additional warming by 2100.

1.8oC = 3.2oF

2.8oC = 5.0oF

3.4oC = 6.1oF

CO2 Eq

850

600

4000.6oC = 1.0oF


Relative to the 1980 to 1999 mean

Global Mean Sea Level


IPCC AR4 Working Group II Report "Impacts, Adaptation and

Vulnerability"• Chapter 4 - Ecosystems, their Properties, Goods and Services

• Chapter 6 - Costal system and low-lying areas

• Chapter 7 - Industry, settlement and society

• Chapter 3 - Fresh Water Resources and their Management

• Chapter 5 - Food, Fibre, and Forest Products

• Chapter 8 - Impacts on human health

http://www.ipcc.ch/ipccreports/ar4-wg2.htm


Vulnerability• 30 to 200

million people at risk of hunger with temperature rises of 2 to 3°C

• 0.7 to 4.4 billion people will experience growing water shortages with a rise of 2°CYields across Africa and Western Asia may fall by 15% to 35%


Ecological impacts of the European heatwave 2003

Relationships between the percentage of species loss and anomalies of moisture

availability and growing-degree days

Thuiller W. et.al. PNAS 2005;102:8245-8250

Future projections for Europe suggest significant reductions in species richness even under mean climate change conditions, and an increased frequency of such extremes is likely to exacerbate overall biodiversity losses.


Mohamed Nasheed Former President of

the Maldives

Wanted: New Home for My Country


Florida with 3 feet of Sea-Level Rise

Coastal areas are at increasing risk from sea-level rise and storm surge.


Impacts


Impacts on Industry, Settlement and Society

• Climate-change vulnerabilities of industry, settlement and society are mainly related to extreme weather events rather than to gradual climate change

• Aside from major extreme events and thresholds, climate change is seldom the main factor in considering stresses on the sustainability of industry, settlements and society

• Vulnerabilities to climate change depend considerably on specific geographic, sectoral and social contexts

• Vulnerabilities of industry, infrastructures, settlements and society to climate change are generally greater in certain high-risk locations, particularly coastal and riverine areas, and areas whose economies are closely linked with climate-sensitive resources, such as agricultural and forest product industries, water demands and tourism; these vulnerabilities tend to be localized but are often large and growing

• Poor communities can be especially vulnerable, in particular those concentrated in relatively high-risk areas

• Industry, settlements and society are often capable of considerable adaptation, depending heavily on the competence and capacity of individuals, communities, enterprises and local governments, together with access to financial and other resources

• Although most adaptations reflect local circumstances, adaptation strategies for industry and settlement and, to a lesser degree, for society, can be supported by linkages with national and global systems that increase potentials and resources for action


Extreme and rare events are increasing with time …


Definition of Extreme Events


Hurricane Katrina

• Landfall on Gulf Coast of US on 29 August 2005 (category 3; several days at category 5 in Gulf)

• Widespread flooding, levee failures in New Orleans (80% of city), Louisiana and Mississippi

• Collapse of I-10 bridge cut off New Orleans exit to east

• Loss of life: 1,464• Damage to many downtown buildings, Superdome,

Convention Center• Civil unrest in New Orleans; refugees turned away

from Gretna, LA at gunpoint


Record Heat Wave – Western Russia 2010

• Highest temperatures in 130 years• Spontaneous fires – peat bogs, crops, forests• 70+ deaths from fire, 2000+ deaths from drowning


PDSI in the 20th

Century

• Eastern North& South America, northern Eurasia are getting wetter

• Africa is getting drier, especially in Sahel

• Very dry areas have more than doubled since the 1970s.


Do the rains follow the plough.... ... or does agriculture promote desertification?

QuickTime™ and a decompressor

are needed to see this picture.

QuickTime™ and a decompressor

are needed to see this picture.

U.S. Dust Bowl - 1930s


Droughts have multiple causes• land abuse• increasing demand on limited water resources• anomalous sea surface temperature patterns

We can’t attribute specific droughts to global warming

but we can say with some confidencethat global warming is likely to increase the incidence of drought, especially in semi-arid regions.

Drought and desertification, in turn, lead to higher daytime temperatures

Global Warming and Drought


Origins of Floods• Flash Floods are typically caused by short, intense rainfall events

over areas as small as a city to larger than a state.

• Riverine Flooding: Widespread excessive rain events produce flooding along waterways throughout the United States.

• Hurricanes: Warm, moist tropical air that serves to drive the winds in a hurricane can also lead to widespread hazardous flooding.

• Ice Jam Floods

• Snow Melt Floods: Warm, moist conditions and heavy rain can combine with snow melt to cause dramatic winter and spring flooding.


Are floods increasing?

Trends in the frequency of flood events are difficult to quantify because

• River configurations and land use are continually changing

• Hourly rainfall data are available only over limited regions of the globe

the data are expensive and there are restrictions on their use

• Floods are rare events, especially when considered season-by-season

Like keeping track of “grand slam” home runs

it’s difficult to establish statistical significance when dealing with rare events.

But we believe floods should become more frequent because warmer air holds more water vapor.


Wet regions become wetter while dry regions become drier

Heavy rainfall events become more extreme

• The Intensity of downpours believed to be proportional to water vapor concentration

• C-C equation predicts that atmospheric water vapor concentration increases with temperature at a rate of 7% per °C

•

How will global warming affect rainfall?

July 26, 2005 downpour in Mumbai, 1 meter of rain in 1 day. Despite the one-day flood, 2005 was a dry year in India.


Recent Flooding Disasters

Time Country Death Toll Event

August 2010 Gansu China 1500+ floods, landslides

August 2010 Kashmir 170+ flash floods

August 2010 Central Europe 15+ flash floods

July-Aug 2010 West Pakistan 1700+ heavy monsoons

June 2010 Southern France 25 flash floods

June 2010 Southern China 200+ floods, landslides

June 2010 Northern Brazil 100+ floods, landslides

June 2010 Poland 15 river flooding

April 2010 Brazil 200+ rain, mudslides

March 2010 Uganda 350+ rain, mudslides

Feb 2010 Xanthia, France 50+ tempest, sea walls

Aug 2005 Katrina, USA 1,800+ hurricane, levees


Main threat to a sustainable Earth

Documents

CLIM 101 // Global Warming, Weather, Climate and Society // Fall 2012 Impacts of Climate Change Impacts on Natural Systems Impacts on Society: Impacts