BY HANS JOACHIM SCHELLNHUBER, PAUL J. …...BY HANS JOACHIM SCHELLNHUBER, PAUL J. CRUTZEN, WILLIAM C. CLARK, AND JULIAN HUNT Much of the media's coverage of science this year has been

BY HANS JOACHIM SCHELLNHUBER, PAUL J. CRUTZEN,

WILLIAM C. CLARK, AND JULIAN HUNT

Much of the media's coverage of science this year has been aretrospective narrative about the universe and our origins withinit: Albert Einstein's annus mirabilis of publications, which upendedunderstandings of time, space, and the atom, celebrates Its cen-tenary in 2005, and one of modern biology's key building blocks,Charles Darwin's Origin ofthe Species, has made headlines as partof a scientific-cultural divide in certain U.S. communities. Whilea great deal has been said about what these important scientificworks have taught us, looming questions remain about our ownplanetary system, our interactions within it, and our ability to steerourselves toward a sustainable future. To answer such large ques-tions, an even more fundamental shift in humankind's researchagenda, particularly regarding the analysis of the total Earth Sys-tem, is in order. Fortunately, such a shift is already under way andwill actually complete a millennium-scale development in the his-tory of science.

In 1543 Nikolaus Copernicus published De Revolutionibus Orbi-um Coelestium, which set the stage for the development of modernscholarship. Not only was the Earth finally put in its correct astro-physical context, but the first principles of "exact and objective"

reasoning, ultimately triumphing in theEnlightenment, were also established:The perception of cosmic reality heldby Copemicus's followers (for example,Galileo, Kepler, and Newton) becamedominated by the clockwork metaphor,assigning a regular trajectory governed byeternal physical laws to each particle in theuniverse. As well, the production of wis-dom became dominated by the curiosity-driven mode, confronting the brightestminds with the ultimate riddles of creationin splendid isolation from sociopoliticalinterests—and from each other. Thus thegreat Copemican Revolution generateda paradigm in which the lonely scholarwrestles with nature to snatch some of hersecrets encoded in mathematical formulaeof utter beauty.

In 2001, delegates from more than100 countries participating in the 4major intemational research program.^ onglobal environmental change endorsedthe Amsterdam Declaration on GlobalChange, which fomially established theEarth System Science Partnership and setthe stage for what one might call a secondCopernican Revolution.' The concept ofthis novel revolution is deeply rooted inthe original one yet transcends it in sev-eral crucial ways;

• The scientific eye is redirected fromouter space to our "living Earth," whichoperates as one single hyper-complexsystem far from the thermodynamic equi-librium characterizing "dead" planets likeVenus.-

• Scientific ambition is requalified byfully acknowledging the limits of under-standing as highlighted by the notoriousuncertainties associated with nonlinearity,complexity, and irreproducibility.' lf theEarth System is a clockwork at all, then itis an organismic one that baffles our bestanticipatory capacities.

• The scientific ethos is rebalancedby accepting that knowledge generationis inextricably embedded in the culturalhistorical context: There is nothing wrongwith being particularly curious about theitems and issues that matter most forsociety or recognizing that the covetedborderlines between observing subjectsand scrutinized objects have often been

mere constructions of a preposterousreductionism."^ Thus, the research com-munity becomes part of its own riddles,the research specimens become part oftheir own explanations, and co-productionbecomes the (post)normal way of copingwith the cognitive "challenges of a chang-ing Earth."''

The Anthropocene

The very fact that the AmsterdamDeclaration resulted from an intricatecooperative process—and not from oneingenious idea of a stand-alone intel-lectual giant—adequately reflects the co-productive mode that will be instrumen-tal for the much-debated "new contractbetween science and society."'' Even asuperficial look at the current state anddynamics of our planet indicates that thesustainability of modem civilization is atrisk without such a contract. For today.

cent of the worid's ice-free land surfacehas been transformed by human action,and the land under cropping has doubledduring the past century at the expenseof forests, which declined by 20 percentover the same period. Further, more than50 percent of all accessible freshwa-ter resources have come to be used byhumankind. Fisheries remove more than25 percent of the primary production ofthe oceans in the upwelling regions and35 percent in the temperate continentalshelf regions. Many enclosed seas (likethe Gulf of Mexico) have been tumed intovirtual dead zones, and many rivers (likethe Colorado, the Nile, and the Huang-He) now reach their coastlines as meretrickles due to human interference.

The same reports also confirm thatmore nitrogen is now fixed syntheticallyand applied as agricultural fertilizers thanis fixed naturally in all terrestrial ecosys-tems. Overapplication of nitrogen fertil-izers in agroindustry and nitrogen's high

LOOMING QUESTIONSREMAIN ABOUT OUR OWN

PLANETARY SYSTEM,OUR INTERACTIONS WITHIN IT,

AND OUR ABILITY TOSTEER OURSELVES TOWARD

A SUSTAINABLE FUTURE.we live in what may appropriately becalled the "Anthropocene": a new geo-logic epoch in which humankind hasemerged as a globally significant (andpotentially intelligent) force capable ofreshaping the face of the Earth past allrecognition.^

An up-to-date understanding of howhuman actions have brought about and areaccelerating the Anthropocene is the nec-essary foundation for any serious effortto hamess science and technology forsustainability. The recent reports of theworld scientific community's decade-longresearch programs on global environmen-tal change and the Earth System providesuch a foundation.*^ Drawing from theworks of hundreds of researchers, thosereports concluded that perhaps 50 per-

concentration in domestic animal manurehave led to eutrophication of surfacewaters and groundwater in many loca-tions around the world. These and otherhuman activities (see below) also enhancethe microbiological production of nitrousoxide (NÔ), a powerful greenhouse gasand a source of nitrogen oxide (NO) in thestratosphere, where it is strongly involvedin ozone chemistry.''

Also affecting the Earth's atmosphereis humanity's exploitation of fossil fuelssince the industrial Revolution, which hasresulted in a large pulse of air pollutants.The release of sulfur dioxide (SO,) to theatmosphere by coal and oil buming is atleast two times larger than the sum of allnatural emissions, which t>ccur mainly asmarine dimethyl sul fide from the oceans.

12 ENVIRONMENT VOLUME 47 NUMBER 8

The oxidation of SO, to sulfuric acid hasled to acidification of precipitation andtakes, causing forest damage and fishdeath in biologically sensitive regionssuch as Scandinavia, northeastern NorthAmerica, and, more recently. East Asia.As a result of substantial reduction in SO,emissions, the situation in the former tworegions has improved somewhat over thelast decades; however, in East Asia, theproblem has gotten worse. The releaseof NO into the atmosphere from fossil-fuel and biomass combustion is likewiselarger than the natural inputs, adding torainwater acidity and giving rise to pho-tochemical ozone (smog) formation inextensive regions ofthe world.'"

Humanity is also responsible for thepresence of many toxic substances inthe environment, particularly the 12 sub-stances (including DDT (dichlorodiphen-yltrichloroethane), PCBs (polychlorinatedbiphenyls). and furans (in particular, poly-chlorinated dibenzofuran, PCDE)} bannedby the Stockholm Convention." Certainother exhalations of the anthroposphericmetabolism, the chlorofluorocarbon gases(CFCI, and CF,CI,, collectively CFCs).are not toxic at all but have neverthelessled to the Antarctic springtime "ozonehole." CFCs would have destroyed muchmore of the ozone layer if internationalregulatory measures had not been taken toend their production by 1996. However,due to the long residence times of thosegases, it will take at least another four tofive decades before the ozone layer willhave recovered. It is crucial to note thatthe discovery of maximum reduction instratospheric ozone came as a total sur-prise. This phenomenon was not predict-ed by "traditional" science; it occurred ina section of the atmosphere furthest fromthe regions of CFC releases to the atmo-sphere and where ozone loss was thoughtto be impossible. The Earth System sci-ence expected to emerge from the secondCopemican Revolution will have to dobetter by predicting at least the possibilityof future "ozone holes"—that is, majordisruptions of some planetary modes ofoperation (see the next section).

Due to fossil-fuel burning, agriculturalactivities, deforestation, and intensive

animal husbandry, several climaticallyimportant greenhouse gases have substan-tially increased in the atmosphere over thepast two centuries: carbon dioxide (CO,),by more than 30 percent, and methane

), by even more than 1(K) percent.

or falling behind are stark reminders thatmuch more remains to be done. However,the fact remains that humanity, on aver-age, has prospered through its continuingtransformation of the Earth. The questionis whether past trends of increasing pros-

HUMANITY, ON AVERAGE,HAS PROSPERED

THROUGH ITS CONTINUINGTRANSFORMATION

OF THE EARTH.Such increases have in turn contributedsubstantially to the observed approxi-mate 0.6''C global average temperatureincrease, which has been observed duringthe past century. The factual evidence forthis development is summarized in thelast assessment report of the Intergovern-mental Panel of Climate Change (tPCC),which also bluntly states, "There is newand stronger evidence that most of thewarming observed over the last 50 yearsis attributable to human activities." '-

There is no question that humanityha.s done quite well by its transforma-tion of the planet. Supported by greattechnological and medical advancementsas well as by access to plentiful naturalresources, we have colonized most placeson Earth and even set foot on the Moon.The transformations of the last centuryhelped humanity increase the amount ofcropland by a factor of 2, the number ofpeople living on the planet by a factor of4, water use by a factor of more than 8,energy use by a factor of 16, and indus-trial output by a factor of more than 40."The quality of human life also increased,with average life expectancy up morethan 40 percent in the last 50 years;literacy up more than 20 percent in thelast 35 years; and substantial improve-ments in the female/male ratio in primaryeducation, the number of people living indemocratic countries, and the increasedcommitment of the international com-munity to protect civilians from internalconflict and defend the rights of nationalminorities.'"^ The uneven distribution ofthese increases, their tenuous character,and the continued suffering of peoples left

perity can be broadened and sustained asthe Anthropocene matures.

The prognosis for continued and sus-tainable improvements in human well-being on a transfonned planet Earth is. atbest, guarded. The U.S. National Acad-emy of Sciences has concluded that overthe next 50 years, human population canbe expected to increa.se by perhaps 50percent. Associated with such an increase,the demand for food production could wellincrease by 80 percent, for urban infra-structure by 100 percent, and for energyservices by substantially more than 200percent.'^ The resulting intensification ofpressures on an already stressed biospherecould be overwhelming.

For example, depending on the sce-narios of future energy use and modeluncertainties, the increasing emissionsand resulting growth in atmospheric con-centrations of CO, are estimated by IPCCto cause a rise in global average tempera-ture by 1.4°-5.8°C during this century.This warming will be accompanied bysea-level rise of 9-88 centimeters hy2100 and of 0.5-10 meters by the end ofthe current millennium. As a matter offact, recent analyses of ice flow dynam-ics in Greenland and Antarctica suggestthat anthropogenic sea change may occureven earlier and faster than IPCC has pre-dicted.'^ According to NASA climatolo-gist James E. Hansen, considering onlythe wanning of the globe over the past50 years plus the warming already in thepipeline—together more than l°C—theEarth will return halfway to temperatureconditions of the last interglacial, theEemian (120,000-130,000 years ago).

OCTOBER 2005 ENVIRONMENT 13

when global sea levels were 5-6 metershigher than at present." However, greaterwarming is expected if humanity can-not drastically curtail the emissions ofCO, and other greenhouse gases. Theimpact of current human activities isprojected to last over very long periods.According to the Belgian climatologistsMarie-France Loutre and Andrd Berger,because of past and future anthropogenic

is, the sum of likely decision outcomesavailable to all relevant actors).'^

A recent Dahlem Conference'" assem-bled an exceptional collection of scholarsfrom all comers of the scientific commu-nity to review the state of the pertinent artand to set the agenda for the further devel-opment ofthe field.'' The conference wasorganized as an attempt to describe thecoevolution of matter and life on Earth

emissions of CO,, climate may departsignificantly from its natural course overthe next 50,000 years.'^ But scientificresearch needs to find out —as soon aspossible—what "significantly" means inthis context.

Earth System Analysis

Is it possible to develop a robust under-standing of the complex Earth Systemjust in time for steering our planet safelythrough the Anthropocene? The answer isby no means a definite "yes," yet there arevarious signs of hope. Earth System sci-ence is perpetually advanced hy thousandsof research projects involving tens of thou-sands of investigators across the globe,and Earth System analysis is emergingas the conceptual, integrating part of theoverall enterprise: It is a transdisciplinestriving to perceive the big picture, to a.skand answer the genuine systems questions,and to identify the prime pathways towardglobal sustainability in strategy space (that

since its very formation and to explain—as far as possible—the planet's systemicproperties in the various stages of thatcoevoJution. Four working groups set outto tackle the intimidating intellectual chal-lenges involved, covering, respectively,long-term geosphere-biosphere coevolu-tion and astrohiology, possible states andmodes of operation of the QuaternaryEarth System, Earth System dynamics inthe Anthropocene, and sustainability.

Long-Term Ceosphere-BiosphereCoevolution and Astrobiology

A remarkable clash of scientific cul-tures was staged in this group, whereglobal change researchers met with spaceresearchers primarily interested in theexistence and habitability of other planetsinside and outside the solar system. Thecommon themes were the general pos-sibility of intelligent life in our universeand the long-term, large-seale coevolutionof dead and living matter through com-plex self-organization processes far from

thermodynamic equilibrium. The groupaddressed a number of exciting issues,such as the evolutionary topology of thebiosphere, the interactive development ofenvironmental dynamics and informationprocessing through the great planetarytransitions, the terraforming potential pro-vided hy Mars, the probability of theemergence of intelligence, and the failureof the SETI project (thus far) to trackdown messages from extraterrestrial civi-lizations. The Gaia theory served as anintegrating factor and unifying metaphorin the group's debates.'-

The admittedly fascinating issuesdirectly connected to astrobiology cannotbe dealt with here, but other discussionstrands that came from this group arehighly relevant for global su.stainahiiity inthe future and deserve elaboration: Withinthe framework of Earth System analysis,the Anthropocene can be perceived as thelatest step on the grand ctx:volutionary lad-der of entwined transitions of information-processing (that is, active) life and force-driven (that is, passive) environment. If wego back in time, we soon encounter the riseof the "hydraulic societies" in the valleysof the Nile, Euphrates, Tigris, and IndusRivers, which were probably founded inresponse to the great drying of the African-Asian regions approximately 6,(KX) yearsago. Before this, organized hunting byHomo sapiens caused mass extinctions ofthe prehistoric fauna: Language providedthe novel inherilaiice system that allowedthe emergence of a society capable ofexerting .such an environmental pressure,resting on complex, negotiated division oflabor. Earlier, the evolution of hominids inthe East African Rift valley was shaped byrapidly changing ambient conditions. Suchentwined environment-information transi-tions have characterized Earth's historysince its beginning approximately fourbillion years ago. The pertinent "coevolu-tion cartoon" is depicted in Figure 1 onpage 15.

Studying and understanding the EarthSystem dynamics encapsulated in the dia-gram should provide us with valuablehints about the potential planetary-sealedevelopments triggered by the Anthro-pocene. For instance, unabated global


Figure 1. Earth's coevolutionary ladder

Environment

Quatematy glaaations ^ o.OO3

End-Permian even! » 0.2S 0.35 jONygen peak I

Carbon dioxide drop 0 4 'V

Life

0 _ | _ 0 0001 •< Natural languBB*® i —

0.09-*- Euaodal coJonlw® |

I Immune aystsm

Nervous system

Extreme olaclaUona »- 0.58("Snowbar Earths?)and relum of BIFs »• 0,75

i i

End of Banded Iron Formettoiw

"IQreelONtdatlonT

2.2 > 2.2*

Huranian glaciatlona I

*

Msthane-rich atmosphera

Impact evenis * • 3.2S

Impact evenU - * 3.47 3.S ' - f * I ' First fOsstl oroanisms

] Chromosomes ®

Lale Impact Catadysm ^ 3 as

CompartmantB®

3SS 4

Ocean formation

Moon formlrtg event ^ 4 52Planet accretion ^ *^

NOTE: Arrows from one side of the time line to the other indicate neces-sary conditions or potential causai connections between the evolution of lifeand changes in the environment or vice versa. Solid lines characterize well-estabiished connections, while broken lines flag more controversialconnections. Error bars indicate uncertainties in timing.

SOURCE: T. M. Lenton. et al., "Group Report: Long-term Geosphere-BlosphereCoeveolution and Astrobiology," in H. J. Schellnhuber, P. J. Crutzen, W. C.Clark, M. Claussen, and H. Held, eds.. Earth System Analysis for Sustainability:Report on the 91st Dahlem Workshop (Cambridge, MA, and London: The MITPress in cooperation with Dahlem University Press, 2004), 111-40.

warming would not only transform theplanetary biosphere beyond recognitionbut probably also enforce the redesign ofhumanity's worldwide self-organizationunder fierce adaptation pressures. (Thischallenging subject will be addressed fur-ther at the very end of the article.)

Quaternary Barth System Dynamics

While the first working group looked atthe total history of the Earth System, thesecond group did a "time slice analysis"to understand the planetary machinery ina specific epoch, the Quaternary (approxi-mately the last two million years beforethe establishment of modem civilization).This period in Earth's development isremarkable because the global machinerywas in a state very similar to the con-temporary one then—yet without humaninterference with crucial biogeophysico-chemical inventories and processes. Spe-cial emphasis was given to the stabilityand variability of our planet's Quaternarymode of operation, an analysis clearlyinvolving the identification and quanti-fication of major feedback loops, phasethresholds, and other critical elements. Animportant di.scussion was held betweenstability optimists (led by the geologists)and stability pessimists (led by the clima-tologists), and the arguments expressedduring this debate resulted in very spe-cific demands for high-quality data forsettling the case.

The latter intellectual controversy ischaracterized in Table 1 on page 16,which summarizes the state of disagree-ment with respect to a shortlist of impor-tant Quaternary issues.'"'

There was unanimous support, however,for the advancement of Earth System mod-eling as the only way to really understandthe roller-coaster glaciation dynamics ofthat epoch. The solution of the "ice-agemystery"—that is, why did the eternal,tiny gravitation-driven variations in theEarth-Sun constellation begin to generatesuch massive effects a few million yeareago?—would catapult the second Copemi-can Revolution forward. In fact, simulationmodels seem to be poised for providing asatisfactory answer soon.^^


Table 1. Bounded consensus tableau for Quaternary mode of operationItem

Ice and sea level

Dominant periods observed in the records

Transition into the Quaternary

Mid-Pleistocene transition

Carbon dioxide (CO^), other greenhousegases, and temperature are highlycorrelated on orbital timescales.

Dust and hydrological cycle

Terrestrial vegetation

Feedbacks

Suborbital changes

Points of agreement

Buildup of massive North American andEurasian ice sheets as well as increases inexisting ice sheets during glacial times.Ice buildup resulted in a maximum -130meter reduction in sea level during glacialperiods.

Orbital forcing is the probable"pacemaker."20- and 40-kiloannum (ka; 1 ka is 1000years) cycles may be reasonably linearresponses to precessional and obliquityorbital forcing, respectively.

-2.6 mega-annum (Ma: 1 Ma is 1 millionyears) B.P. (before present) transition fromsmaller d'^0 variations at -20 ka period tolarger variations at -40 ka.

-900 ka B.P. transition to dominantperiod -100 ka.

Positive feedbacks link CO^ andtemperature. CO^ oscillates betweenbounds -190 parts per million (ppm)to 280 ppm.

Glacial periods are drier and dustier thaninterglacial periods.

Terrestrial biota have lower biomass inglacial periods.

Positive feedbacks amplify climatesensitivity to insolation.Feedbacks include ice albedo, water vapor,land surface albedo, methane (CH^), andatmospheric CO^.

Rapid warming events are recorded inGreenland ice cores during last glacialperiod (Dansgaard/Oeschger events).The dominant theory is that these arerelated to changes in ocean circulation inthe North Atlantic.Cold events are associated with ice-rafterdebris layers (Heinrich events), indicatingmassive amounts of iceberg calving.

Outstanding or unresolved issues

Mechanisms accounting for buildup anddestabilization of ice sheets are not fullyestablished.

There is no agreed explanation for thestrong response at the 100-ka orbital cycle.

The cause ot the transition is disputed.

The cause of the transition is disputed,

The influence of COp on temperatureis well understood, but the influence oftemperature on CO^ is still unresolved. Anumber of competing theories exist aboutwhy the ocean takes up more CO^ duringcold phases.What sets the bounds of CO^ variation isnot resolved.

The influence of temperature on thehydrological cycle is broadly understood,but details are not.

Dust in the Vostok core precedes changesin temperature.

The extent of the change is disputed.

The strength and importance of some ofthese are uncertain.Mechanisms for CO^ feedback areuncertain.

It Is unclear what triggers the changes inocean circulation.

SOURCE: A. J. Watson, et al., "Group Report; Possible States and Modes of Operation of the Quaternary Earth System," in H.J. Schellnhuber, P J. Crutzen, W. C, Clark, M. Claussen, and H. Held, eds,. Earth System Analysis for Sustainability: Repori onthe 91st Dahlem Workshop (Cambridge, MA, and London: The MIT Press in cooperation with Dahlem Universitv Press. 2004)192-93.


Earth Systetn Dynamicsin the Anthropocene

Almost everything on Earth has changedwith the advent of Homo sapiens and theestablishment of the modem anthropo-sphere. The third working group made theheroic effort to describe how the humanfactor has already modified the planet'sQuatemary mode of operation to identifypotential anthropogenic phase transitionsahead, to specify the scientific advance-ments necessary for timely anticipationof dangerous Anthropocene dynamics,and to assess the prospects of large-scaletechnological fixes of the acceleratingsustainability crisis all around us. An in-depth analysis of the notorious climatesensitivity conundrum and a thoroughdelineation of Earth System geographyin the Anthropocene (intercomparing therole of the mid-latitudes to the tropics andthe polar regions) were among the high-lights in the group's deliberations.

A substantial part of the discussionsin this group focused on the confirmedand suspected "Achilles' heels," or tip-ping elements, in the planetary system.The crucial question was whether thosecritical elements most susceptible to trig-gering by human actions can be identifiedin good time to avoid abrupt—and mostlikely devastating—global change.-^

For illustration, a biogeophysicalsubset of potential tipping elements/processes in the Earth System is compiledin Figure 2 on page 18. Its entries areunderpinned by research results of rathervarying conclusiveness, and the collec-tion is far from complete. In fact, newsuspects are identified by global changeresearch almost every year, such as theIndian monsoon, which may be pushedinto a see-saw dynamics by the combineddriving forces of anthropogenic glob-al wamiing. anthropogenic regional airpollution, and anthropogenic local land-surface transformation.-^

At a recent climate change conferencein Exeter. England, convened on behalfof British Prime Minister Tony Blair as astepping stone toward the July 2005 G8Summit,-'^ many of the items in Figure2 were scrutinized, and a novel criti-

ca! element of highest iniportance wasflagged: The direct acidification of theoceans due to anthropogenic atmosphericCO, enrichment is likely to trigger dra-matic changes in marine ecosystem struc-ture and marine biogeochemical cycles.Human interference has already broughtabout an average oceanic pH reductionof 0.1 units since the industrial revolu-tion, and model calculations suggest thatbusiness-as-usual burning of fossil fuelscould provoke a staggering further reduc-

has not yet begun: What are the irreplace-able components of the global indus-trial metabolism? On which agriculturalregion will future world food productioncrucially depend? Are there institutionsthat can preserve/establish social cohe-sion and intemational equity throughoutthe globalization process? Which of thecurrent mega-cities are bound to implodeultimately, and where will the new plan-etary centers of knowledge productionlie? What technologies have the potential

THE DIRECT ACIDIFICATIONOF THE OCEANS DUE TO

ANTHROPOGENICATMOSPHERIC CO2

ENRICHMENT IS LIKELY TOTRIGGER DRAMATIC CHANGES

IN MARINE ECOSYSTEMSTRUCTURE AND MARINE

BIOGEOCHEMICAL CYCLES.tion of more than 0.7 units—outdoing allacidity changes during the last 300 mil-lion years.-''

Yet we may be heading for additionaltrouble: Various newspapers reportedgrowing concerns among Russian ecolo-gists that the Siberian forests—the largestboreal ecosystem on Earth—has becomehighly vulnerable to conflagration underthe multiple stresses of global change.^" In2003, 22 million hectares of spruce, larch,fir, scots pine, and oak were destroyedor damaged by fire. On one day in Junethat year, a U.S. satellite recorded 157fires across almost 11 million hectares,sending a plume of smoke that reachedKyoto, Japan, approximately 5,000 kilo-meters away. A (partial) collapse of theSiberian forests in response to climatechange would accelerate the latter byadding enormous amounts of CO, to theatmosphere and thus contribute to a self-amplifying greenhouse dynamics."

While the criticality analysis of theplanetary ecosphere is making good prog-ress and promises to eventually supportglobal stewardship, the complementarycriticality analysis of the anthroposphere

to transform radically humanity's inter-actions with its natural resources andits life-support systems? Genuine EarthSystem analysis for sustainability needsto address all these questions, but therewill be no quick answers under business-as-usuai conditions. A crash program onthe caliber and scale of the ManhattanProject may actually be necessary todeliver before all windows of opportunityclose down.

Sustainability

The most difficult task of all remainedfor members of the fourth group, whowere to transgress the borderline betweenpurely analytical reasoning and solution-driven strategic thinking. In other words,the group tried to identify pathwaystoward global sustainability, to evaluatethe conceivable management schemes forsteering our planet clear ofthe Anthropo-cene crisis, and to imagine all the scien-tific, technological, socioeconomic, andinstitutional innovations necessary forimplementing the right strategy. A num-ber of heated debates ensued over issues


such as adaptive management; participa-tory decisionmaking; integrated systemsof production, consumption, and distribu-tion; capacity building for coping withenvironmental change; and upscaling ofsuccessful local/regional institutionaldesigns. The discussions culminated intwo interrelated strands: The group stroveto sketch the cruciaJ features of a futurescience-policy dialogue that allows forthe true co-production of sustainabilitywisdom, and it attempted to derive thepertinent conclusion.s for the novel orga-nization of science and technology in thetwenty-tlrst century.

The group specifically focused on thenature and potential role of participatorydecisionmaking at the Earth System level.Participatory decisionmaking has beenpromoted as being capable of resolvingmany global and regional environmentalproblems. There are many benefits ofsuch participation—not the least of whichis securing people's rights in industrial-ized societies. However, can we presup-pose that such inclusive systems automat-

ically, or even usually, achieve outcomesconsistent with fostering the long-termsustainability of the Earth System'.' Thereare many reasons to believe, in fact, thatsuch processes are inherently ill-equippedto grapple with the complex dynam-ics that span large spatial and temporalscales. There may be a tension between"rightness of procedure" and "goodnessof outcome. "^-

Despite the difficulties, for reasonsoutlined below, it is important to supportparticipatory decisionmaking wheneverpossible—^without supposing that suchprocesses would u.sually be democraticin the strictest sense of the word. Nego-tiation of the values society holds or willhold is legitimately within the purview ofevery stakeholder or citizen. Therefore,scientists ought not have, per se, a stron-ger voice in that negotiation than anyother citizen, yet they should have a dom-inant role in determining the likelihood ofvarious future scenarios and their coursesand impacts (both beneficial and harm-ful). Similarly, others with specialized

knowledge (for example, lawyers, histori-ans, and economists) will have particularroles to play. Final decisions that weighscientific, economic, political, social, andcultural considerations are ultimately inthe hands of legitimately recognized rep-resentatives or leaders—^when they exist.Many countries, unfortunately, lack suchlegitimate leadership.

A number of factors are relevant toa consideration of the role of participa-tory decisionmaking in addressing EarthSystem issues; for the most part, theycan be divided into the following threecategories:

• Rationale. Wide participation onthe part of the interested parties may headvocated for normative or instrumentalreasons. Normatively, participation maysimply be regarded as good in itself.Instrumentally, participation may gener-ate creative input into decisionmakingprocesses or increase the willingness ofaffected parties to implement or complywith commitments made during decision-making processes.

Figure 2. A world map of global change Achilles' heels

Instability of .Salinity Valvi —^-Gr'e'eTTrarid'lce Sheet?

Climatic Change-Inducedzone Hole?

BistabilitySahara rt

Vegetatsoon

Transfor^mat

BIstabllity,/Collapse ofAmazonian

Southern Ocean Upwetling /Circumpotar Deep Water Formation

Antarctic Ozone Hole

SOURCE: H. J. Schellnhuber, 2005.


• Types of participation. Different typesof participation may be more or less rel-evant to decisionniaking on Earth Systemissues. For example, interested or affectedparties may be allowed to vote or merelycomment, participate in setting agendas ormaking final choices among options, orhave equal or differential weight in mak-ing choices.

• Types of decisions. Participation onthe part of interested or affected partiesmay be more important for some types ofdecisions than others. For example, partic-ipation is highly important in making basicvalue decisions (such as choices regardingsocial justice versus economic growth) butrelatively less important in making highlytechnical decisions (such as how to mea-sure concentrations of greenhouse gasesin the Earth's atmosphere). In practice,most decisions or choices are likely to fallsomewhere between these extremes. Itwould be helpful to place different typesof choices on this spectrum and to makedecisions about appropriate levels andtypes of participation accordingly.

A number of additional challengesemerge when applying participatory deci-sionma3dng to problems of sustainabledevelopment, First, it is difficult to includeall interested or affected groups: Membersof future generations will be irrevoca-bly affected by our actions but cannotbe strongly or accurately represented.In addition, even for present-day stake-holders, identifying and enlisting thosewho should be involved can be daunting,becau.se potential participants extend fromindividuals to entire nations. Second, itproves challenging to convey the com-plex science involved to tbose who must

negotiate what values should prevail (allcitizens) and those who must make deci-sions. There are no simple answers to thischallenge, and it must be recognized thatmany, if not most, of the participants mak-ing decisions about our complex world doso with a limited scientific understand-ing as well as witb diverse perceptions,opinions, and interests regarding whatshould be done. Third, participatory pro-cesses may favor "consensus" solutionsthat reflect tbe need for political com-promise and incrementalism, rather thanreflecting environmental exigencies thatmake such compromises environmentallyand socially intolerable, even when themajority of participants wish to avoid suchan outcome. Finally, tbe inherent dispar-ity among interested parties ultimatelytends to favor tbe rich and powerful,botb within a society and between societ-ies. Participatory processes devoted toquestions of sustainable development willhave to find a way to strengthen and per-haps (given the forces orienting us toward

that ensure that the political exigenciesof participation do not override the envi-ronmental exigencies of the problembeing addressed.

Emerging Keysto Global Sustainability

We cannot predict whether a world-wide transition to sustainability will beachieved before tbe crucial windows ofopportunity close down one by one. Theproblem may be that tbere are actu-ally too many "solutions" available forcoping with the Anthropocene crisis, sohumankind might remain foolish enoughto adopt no particular one at all. Globalsystems analysis should help to overcomethis dilemtna by highlighting key ele-ments in strategy space that can bringabout sustainability and meet certain cri-teria such as optimality. timeliness, andequity. It may be sufficient, however, tosimply single out a few approaches thatreally can work—and to forget about thepossibly more sophisticated and noblerest. The few approaches tbat follow maybe instrumental in attaining sustainabilitydue to their systemic character.

Political Upscaling: The Earth Alliance

Why is it so difficult to deal with globalproblems like climate change? The obvi-ous answer is that the political actorscurrently trying to solve these problemsthrough negotiations are the more than

A NUMBER OF CHALLENGES EMERGEWHEN APPLYING PARTICIPATORY

DECISIONMAKING TO PROBLEMSOF SUSTAINABLE DEVELOPMENT.

the rich and powerful) favor the poorand disenfranchised.

Participatory processes can broadenthe legitimacy accorded to environmentaldecisionmaking and thereby increase theconcem and commitment of a range ofactors in society to the goal of sustainabil-ity. At the Earth System level, however,the processes must be designed in ways

200 nation-states on Eartb. This meansthat the challenges of the twenty-firstcentury and beyond are addressed byinstitutional structures sbaped in the nine-teenth century. Moreover, the institutionvested with nominal authority over issuesof intemational govemance, the UnitedNations, is in the midst of a deep motiva-tional and organizational crisis and has not

OCTOBER 2OO5 ENVIRONMENT 19

managed so far to adequately retlect theparamount importance of global sustain-ability issues in its institutional makeup.For instance, the United Nations Environ-ment Programme (UNEP) and the Com-mission for Sustainable Development(CSD) are relatively inferior componentswithin the overall architecture, short onpower and resources.

There are some indications, however,that this unsatisfactory state of affairsEiiay be changed soon. UN Secretary-

wake of the 2002 World Summit on Sus-tainable Development in Johannesburg,however, especially through the formu-lation of the Millennium DevelopmentGoals (MDGs), the vessel launched at Riobecame increasingly tilted away from itsenvironmental board.

The critical issue of poverty reductionhas recently gained center stage on theinternational agenda, as evidenced by theUN Millennium Pioject report Investing inDevelopment: A Practical Plan to Achieve

WHY IS IT SO DIFFICULT TODEAL WITH GLOBAL PROBLEMS

LIKE CLIMATE CHANGE?General Kofi A. Annan has asked formore integrated structures dealing withenvironmental protection in the UN Sys-tem, and environmental secretaries ofstate from several European countrieshave asked, in an open letter publishedin various newspapers in May 2(X)5, for aproper UN environmental organization ofcomparative weight as the World HealthOrganization (WHO) and the Food andAgriculture Organization of the UnitedNations (FAO).-" These political state-ments support a much broader and boldervision developed a few years ago bythe German Advisory Council on GlobalChange (Wissenschaftlicher Beirat derBundesregierung Globale Umweltveran-derungen, WBGU), namely the notion ofan "Earth Alliance," as described in thebox to the right.

The Forgotten Integration:Reviving Rio

In its last report,"* WBGU wentone decisive step further: The councilpointed out that the institutional struc-ture (sketched in the box) would consti-tute an ideal platform for redeeming thegrand promise made by the statesmen andwomen of the world in 1992 at the UNConference on Environment and Devel-opment held in Rio de Janeiro—namely,to unite global environmental policy withglobal development policy for bringingabout planetary-scale sustainability. In the

the Millennium Development Goals, forwhich economist Jeffrey Sachs was leadauthor.^^ However, the i.ssue's prominencemust be tempered with the realizationthat the MDGs (and particularly theirnecessary longer-term extrapolations) willnot be achieved if global environmentalchange is treated as a marginal issue with-in the wide development field. Neitherwill they be reached if decisionmakers failto exploit the tremendous synergies thatcan be released by an integrated sustain-ability policy. The central WBGU thesisis "poverty reduction through environ-mental protection," not "poverty reductioninstead of environmental protection" ascertain neoclassical economists tend toargue. In fact, WBGU envisages a global"viitual circle" dynamics.

Under this paradigm, serious envi-ronmental concerns in the industrializedworld (such as fears about the tipping phe-nomena associated with global warming)lead to heavily increased investments inthe developing world (through the CleanDevelopment Mechanism under the KyotoProtocol, for instance); generate, as a cru-cial "side effect," sustainable economicgrowth there; reduce, in turn, the pressureson natural resources; emancipate the peo-ples in the developing world from short-term thinking imposed on them by sheerneed; and thus, finally, enable developingcountries to join the "preservation club"of the industrialized world, lt almost goeswithout saying that environmental protec-

THE EARTHALLIANCE

The German Advisory Council onGlobal Change's (WBGU) vision ofan Earth Alliance to reform Ihe archi-tecture of international environmentalin.stitutions and organizations buildson existing structures and developsthem furihcr as needed.' As sketchedin Ihc figures heiow. the Earth Alli-ance comprises Ihree crosscuttingareas inlcrlinked in lerins of csscri-lials like intbrmiition, communica-tion, coordination, and finances. Firsi,to enhance ihe assessment of environ-mental problems. WBGU proposesthe establishment of an independentenlily with Ihe task of issuing (early)warnings of developEiient trajectoriesthat harbor particularly high risks.Second. WBGU recominends changesin the organizational hub of inter-national environmental policy. Thiscenters on the stepwise establishmentof an international environmcnUilorganization—involving the coordi-nation and cooperation function ofa strengthened the United NationsEnvironment Programme (L'NEP).wilh closer networking among the.secretariats of the international envi-ronmental conventions and their (insome instances yet lo be established)scientific advisory bodies. Third, inaddition lo legal certainty and goodgovernance, sufficient financialresources are necessary to countergrowing global challenges success-fully. However, the reluctance of ihcindustrialized countries to provideadequate funding—which has becomeincreasingly entrenched over iheyears-—poses an obstacle lo the rais-ing of adequate funds to prolecl glob-al environmenla! resources, WBGUrecommends tha( inno\ative avenuesfor funding global envin)nmenlalpolicy be pursued increasingly.-

1. German Advisory Council onChange (WBGU). CImrgmg llw Use oftheGInhiil Ommons (Berlin: WBGU, 2(H)2}.

2. WBGU, World ill Tnwsition: Fiiilii-iriji Poverty through Eiiviroiiiueiuu! Policy(London: Earthscaii. torthconiing 2(X)5).


Tfusteflship for theglobal commons

Alt space

User

OL,rer space charges

Monitoring.Early warning.

Inlormaiion

NOTE: Figure "a" indicates today's status, and figure "b" is a vision of retorm.

SOURCE: German Advisory Councii on Global Change (WBGU), World in Transition: New Stnjcturesfor Global Environmental Policy (London and Sterling, VA: Earthscan, 2001).


tion policies implemented by developedcountries (like greenhouse gas emissionreductions) are the absolute preconditionfor keeping the vulnerability of develop-ing countries within a manageable range.A systems-analytic sketch of such a "Riostrategy" (or sustainability strategy) isgiven in Figure 3 on page 23.'*'

Politicai Downscaiing:Coaiitions of Cities

If the concerted planetary managementby nation-states under the roof of theUnited Nations (that is, at a global gov-ernance level) is unfeasible, then thereis still the option to reverse directionentirely for approaching susiainability: Abottom-up strategy motivating and con-necting willing subnational actors andbodies worldwide seems to provide amuch better perspective in a politicaluniverse where one single country is ableto slow down (or even stop) all well-meaning multilateral initiatives. Thegrassroots heroes in the climate changebattle, for instance, could be the citiesthai arc prepared to face the global changechallenges overshadowing all their lon-ger-term planning schemes.

City governments already observe wor-rying changes in their local climates andenvironments, which will generally haveworse impacts than corresponding devel-

opments in sparsely populated areas andare likely to jeopardize even the viabilityof the cities themselves. The temperaturerise in urban domains may exceed by5°C those in the surrounding country-side, where anthropogenic warming isexpected to amount to 4°~6°C on most ofthe continents. This notorious heat islandeffect, which is greatest in the evening,comes largely from buildings that emitand store heat. But of greater concern forthe well-being of humans, other animals,and plants is the prospect that heat waves

flood structures. In Hamburg, the dykesare being raised to ensure the long-termviability of the port, and in London, theThames River barrier may eventually beincreased. There are, however, other areasin the United Kingdom and throughoutthe world where cities and rural commu-nities will have to retreat from the coastand watch their settlements disappear—perhaps the ultimate democratic challengefor a local community. The hot spots ofthe sustainability challenge are, in fact,the coastal mega-cities in the developing

THE CRITICAL ISSUEOF POVERTY REDUCTIONHAS RECENTLY GAINEDCENTER STAGE ON THEINTERNATIONAL AGENDA.

will become much more frequent accord-ing to the latest scientific estimates andcould lead to the recurrence of the disas-trous ambient conditions experienced inLondon and Paris in 2(K)3." In addition,there are negative synergies: Heat wavesare likely to be associated with stronginversion conditions that will trap airpollution in urban domains and assist thelateral transport of ozone and similarlytoxic gases between neighboring cities.An equally serious environmental effectof climate change in densely populatedareas is the greater likelihood of flood-ing caused by intense, more frequentrainfall events, by sea level rise, and bythe relentless anthropogenic expansionof impervious surfaces. In the last 10years, the United Kingdom and continen-tal Europe have experienced some of thelargest floods ever recorded, provokingenormous economic tosses. The 2002Elbe River flood alone caused damagescosting more than US$15 billion.

But lessons have been learned aboutreducing the future impacts of floods byusing temporary and permanent struc-tures, more resilient building designs and,above all, better planning of built-upareas. In Houston, for example, eco-logical communities are working withnature to reduce the need for concrete

world, where the two dominating trendsof global change, namely climate change(implying sea-level rise) and urbanization(driven by socioeconomic globalization),collide to wreak havoc.

On the other hand, cities themselveshold the key to environmental protec-tion—if national governments allow (oreven encourage) them to use it: GreaterLondon consumes more energy Ihan dosmall nations such as Portugal or Greece,and London's mayor has now set up aregional climate change agency to mas-sively reduce the city's greenhouse gasemissions. Toronto has pioneered city-wide energy-saving schemes, and Singa-pore has initiated congestion charging toreduce automobile carbon emissions—aswell as to deal with traffic jams, Increas-ingly throughout the world, urban plan-ning is required to have as its objectivethe sustainabilily of local communities.Seattle is spearheading a cities coalition inthe United States to fight global warming,even beyond the obligations that wouldhave arisen from the Kyoto Protocol hadthe United States ratified it. Because oftheir significant regulatory and executiveautonomy, cities can often do what entirenation-states cannot agree to do. So, cli-mate protection may be pioneered in thenext decades by hundreds of willing city


governments***— joining forces with othersubnational etitities (such as the State ofCalifornia, if recent speeches by Gover-nor Arnold Schwarzenegger will translateinto policy) and supranational entities(includitig international corporations suchas BP and HSBC), Earth System analy-sis for sustainability tieeds to carefullyexplore the potential benefits (and risks)involved in such a change of course.

Ultimate (Un-) Sustainability:Auto-£voiution

The Anthropocene can be perceivedas a period of accelerated coevolutioti.driven forward at an unprecedented paceby an unprecedented force, namely Homosapien.s' collective intelligence. The cur-rent anthropogenic transformation of theecosphere (in particular, anthropogenicclimate change) will create cascades of

impacts on natural and socioeconomicsystems, which—in turn—will provokehigher-order cascades of adjustments andresponses. This will most likely also resultin a major reinvention ofthe driving forceitself: human culture.

The need to adapt will undoubtedlytransfomi our ways of satisfying the basicneeds for food, freshwater, health, shelter,and mobility. For instance, new geostra-tegic modes of agricultural productiotiwill have to be established under thecombined stresses of global warming.soil degradation, and biodiversity loss.The current ratio of terrestrial versusmarine protein harvesting might need afundamental revision. On the other hand,meter-scale sea-level rise and progressiveoceati acidification''' may considerablycomplicate such a revision and requirethe restt^cturing of most of the platiet'scoastal zones.

The need to mitigate or limit globalchange to matiageable dimensions willundoubtedly bring about the reorganiza-tion of humanity in geographical, cultural,and political space. For instance, the con-tainment of energy and material demandsrequires a reassessment of all productionand consumption modes and a revalua-tion of the urban-rural nexus. The han-dling of environmental problems strikingat all scales asks for novel institutionalstructures, connecting global with localdecisionmaking.

Thus, ironically, modem humanity'sreckless exploitation of the ecospheremight trigger the transition to a newglobal form of social aggregation, whichUniversity of Sussex zoologi.st AlisonJolly dubbed the "Fifth Step" of emergentself-organization of matter.""'

While this further step up the eoevolu-tion ladder would be an altogether positive

Figure 3. Climate-focused sustainability strategy generating positive feedbackloops between environmental and development policies

Sustainableinvestment,e.g. energy Financmg and

governanceinstruments

CompensationpaymentsVulnerability

reduction

Sustainableconsumption anc

productionpatterns

Promotion ofsustainable economic

growth

servation of ecologiesintegrity nnd diversityLI iliaric icy

the operabiiityof markets

Prevention ofdangerous climate changeStrong post-Kyoto regime

Catalyst:Transfer of low-emission

technologiesCatalystDevelopmentcooperation Conservation of natural

carbon reservoirs andsinks: Forest protocol

Reduction ofabsolute poverty conflict preveniion

SOURCE: German Advisory Council on Global Change (WBGU). Worid in Transition: Fighting Poverty throughEnvironmental Policy {lontion: Earthscan, forthcoming 2005).


outcome of the Anthropocene crisis, thelatter may provoke other planetary-scaleresponses of a more questionable char-acter. For instance, the global wanningthreat has prompted a number of respect-ed scientists to consider "geoengineeringschemes""^' for counteracting anthropo-genic climate forcing. These schemesrange from quite dubious proposals (likemanipulating planetary insolation throughgigantic miiTors in outer space) to poten-tially feasible suggestions based on solidscience (like the massive extraction ofanthropospheric CO, through physico-chemical precipitation^" or the judiciousinjection of SO. into the stratosphere"^-*).

answer to the coevolution riddle. How-ever, it is timely to start thinking about thelonger-term prospects ofthe Earth Systemas guided (or misguided) by a "GlobalSubject,""'"^ that is. a post-AnthropoceneLeviathan representing humanity's collec-tive self-conscious willpower.

Earth System matiagement couldexplore the following options:

• Planetary (ie.sign—the fixation oramendment ofthe ecosphere according tohumanity's preferences (using, inter aha,geoengineering and nanotechnology):

• Pure auto-evolution—the fixation oramendment of humanity hy itself (forexample, through gene technology).

But there are also first discussions about"macro-adaptation" options like divert-ing rivers for compensating precipita-tion pattern shifts or assisting ecosystemsmigration in response to global change byestablishing transnational unfragmentedbio-corridors (for instance, across theCentral American isthmus).

These are just a few possible roadstoward medium-term Earth System man-agement, but where will these roads ulti-mately lead to? Is there something like acommon vanishing point? Stanislaw Lemhas dreamt up such a point in his science-fiction novel Solaris, where information-processing life and geophysical forceseventually merge into one single plan-etary entity. Lem's ingenious constructionis good intellectual fun but hardly a robust

partially in response to environmentalpressures, partially for completely inde-pendent reasons, and guided by purelycultural criteria (related, for example, tohealth or aesthetics standards): and

• Controlled coevolution—the estab-lishment of a process where humanityperpetually reinvents itself, nature, andthe respective interactions—either spon-taneously (on the pertinent time scales)or in agreement with some unshakableprinciples laid down once and for all.

It is critical to emphasize that the lastscenario is the most realistic and desir-able one. Wise stewardship could translatethis pathway into "sustainable auto-evo-lution," with the right balance betweenconservation and innovation, nature andcivilization, and responsiveness and

autonomy. The immense challenge is tostart seeking those criteria and principlesthat might define the "sustainability" ofsuch an Earth System future, where infor-mation-processing organic matter wouldultimately rule and shape its cosmos with-out any constraints except the most funda-mental laws of physics. So let us considerlaunching the first explorative ship ever tosail into this uncharted ocean.

Hans Joachim Schellnhuher is the founding dirccior ol"ihc Pasdani InsuEuie lor Climuie Impairi Rest-arch and aprot'cssiir of ihtMrciifal physics al ihe L'niversiiy of Pols-Jam. In addition, he is ihc rcscaa'h director of the TyndallCentre f<ir Climate Change Rcsicarfh and a professor atihe Environmental Sciences Schoiil nf ihc Lfniversiiy ofEasi Anglia in Norwich. UK. He was awaixled in 2(X)2ihe Royal Society-Wo If son RL-seiirch Merii Awaiil andin 2004 Commander of ihe Briii.vh Kmpire (hy Qu' '-'nHIi/abelh II). He is also a mcmher of ihe U.S. NationalAcademy of Sciences. researL'h lellow n!' the RoyalSix.iet_\, antl amhitssiidor for the International (ieiispherc-Biosphcre Programme (IGBPl. In addition, he i\ vice-chair of ihe German Advisory Council on CiUiha! Change(WBGU). L-haimian of the Global Change AdvisoryGroup for the fitli Hraiiifwork Programme of Ihc KunipeunCommission, and mcmlvr o!' the ScicniiHc Buinl of ilieDahiem Conferences. Ik has iiuhlishcd inoa' thaii I Mlarticles and .'0 hiHiks on solid st;iii; physics, ihe iheoryof tonipiex nonlinear syslcnis. ilimatc inipaci a'search,Euinh SyMcm an;ilysis. and integrated assessnieni. Hecan he vomacied via e-maii ai li,j.sL'hetlnhuherft?'iica.ac.iik. Paul .1. Cnii/t^n is a pniffssnr emeriltLs al ihe M;wPlanck Insiiiuie for Chemistry and and senior sticmisi atihe Scripps Inslitulion of Oceanography at tlio Llnivcr. iiyof Ciilifoniia. Sati I>iego. His current rcsearcii fix-usos onllie inipaci of atmospheric hmwn clouds on diniaie atiilhydrological cycles, especially in Asia. He al.so currentlyserves as member ol' ihc .Steering Committee oC the Cen-ter for Atmospheric .Sciences. University of Califomia,Berkeley: menibei- of ihe Framework Prograttime ExpenAdvisory Grtiup (EAG) on "Glohal ehange. climate andhiodi versi ty," European Commission. Brussels; nietiiberof the advisory eomntillee of ihc Advanced Instiiute onUrbani/aiion. Emissions, and the Gloha! Carhon Cycle.The glohal change SysTem for Analysis, Research andTraining (START). Washinglon 1X7: and niemher of tlieInteniaiional Polar Foundation. Brussels. He was awardedihe 1995 Nohcl Pri/e in Chemistry wilh Mario Molinaand SherAixtd Rowland, Cmi/en may be ivached atair@mpch-main/..mpg.de. William C. Clark is ihe HarveyBrooks Pro lessor of 1 me mat ional Science. Puhlic Policy,and Human Development at Har\ard Universiiy's Ken-nedy School ol' Government. Trained as an ecologisl. hisresearch lociisoi on the interactions of envimnment anddevelopmeni and on security concerns in inteniaiionalaffaii-s. Among ihe most recent puhlicatioas he hus cix'd-iied are Eeirih Sy.trcms Anaty.<i>s fur Smtaimihiiiiy (MW.2004) and Leiiniing m Mtinaite Ghhal EiivinmmciiiaiRi.\ks (MiT. imw. He co-chaireil ihe U.S. NationalResearch Council study Our Cimmoii Jimiviy: A Tnin.si-lion TtiwanlSimaimibitiiy and the Hcin/Center study TIwSiare of the Naliimx Etctysli'iiis: Mrcnuniii- ibr tjuuls.Wtiicrs. and Livirtii Ri'.tinmv.i nf ihf i'liin-iJ Sratrs (Caiii-hridge. 201)21. Clark is a member of the U..S. NationalAcaiiemy ol' Scienees and is a njcipienl of the MacAiihurPri/c. the Humboldl Prize, and the Kennedy SCIUKO'SCiu-hallo .AwanI for excellence in teaching. He h an execu-tive eililor of t'lrinuwicif. He can he contacted via e-mailat william_cl;irk<n'harvanJedu. Julian Hunt is a pnifes-sor ol' climate modeling at the Iêpanment of Space &Climate Physics and ot liarth Sciences at University Col-lege London (UCL). He is also :in honorary' profes.sor ofmathematics at UCL. In addition, he is a fellow at Trinity


College Cambridge: an honoraiy prol'essor in the Depart-iufnt of Applied Maihemaiics ami Tlieoreiical Physics,University of Cambridge: and liic J. M. Burgers VisilingPmtes>M)r ai ihe Dellt L'nivcrsiiy ot Tecbnology, Delft,Netherlands. He \s alwi director of LighthiH Insiitute ofMaihematicui Scienees. He was director-genera) and chiefexecutive of the Mcieonilogical OITicc (the Met Ofricc)in Exeter. UK, ln>ni l"W2-i997 aiid was appoinieii as aworking peer in llie House ol' Lords, with ihc tiile BaronHum of Chesterton, in 2()0().

NOTES

1. The four internalional rcM';irch progriims ihalenUoi-scil lhe /Hriisierdum [XH-'luration and now make upIhc l- inii System Science Partnership are ihe IniemaiioiialGc'osphere-Biosphere Piugramme (IGBPl. lhe hiienia-licnal Muinan Dimensions Programme on Global Envi-roiimemal Change lIHDP). lhe Wfirid Climaie ReseajvhPnigramme (WCRP). and tlie inlemiillonal biiKliver.'-iiyprognmi DIVKRSITAS. For IIIOR' inlormation on thepannership, see hiip://www.essp.org/; and B. Moore III.A. I'ndordal. P Lemke. anil M. Lorcau. "•'I'he Anister-ilam Detlaiaiion on Glohul Change." in W. .Stcften. J.Jiiger. D. J. Cui'Mm. ami C. Bradsiiaw. cds.. Chatieiigesiifu Clmnîn^ Eiirili: I'niiwdinft.i of ihe Glohcil ChangeOpen Science Confercmt: Ainslerdiim. The Netherlands.10-13 July 2001 (Berlin. Heidelberg, ant! New York:Springer. 2002). For more infoniialion on the lerm"'seeond Copemiean Revoluiion," see H. J, Schellnhuber,""Eanh System' .Analysis and the Second CupemicankcvoUiiion." Nature. 2 Decemher 1999 I Millenniumsupplenien[|,CI9-C23.

2. J. Lovelock, "The Living Eanh." Nuime. 18 Deeem-ber 2(Xi3. 7W-70.

.1. H. J, Schellnhuher, "Coping with Eaiih SysicmComplexity and Irregularity." in Sieflcn. Jiiger, Carson.aniJ Bradshaw. note I above, page 151.

4. H. Nowotny, P. Scotl, and M. Gibhons, ReTiiinkingScience: Knnwledge und lhe Puhlic in an Age nf Uncer-tainly (Cambridge. UK: Polity Press, 2001),

5. Stcffen, i&get, Carson, and Brad^ haw, note Iabove.

6. J. Luhehcneo. "Entering thcCcntury of the Environ-ment: A New Social Coniraci tbr Science," Science. 23January 199M. 491-97.

7. P. J. Crutên. "Geology ol' Mankind." Nature. 3J muury 2002. 23,

H. See. in particular, the recent IGBP book series pub-lislietlby Springer (Berlin). The series' flagship volume isW, Stet'l'cn el al,. Glalwl Change and the Eanh System: APtunei Under Pivsûre (Berlin: Springer. 20()4),

9. An excellent review of global impacts of land use isprDvided by J. A. Foley et a(,, "Global Consequences ofLind Use,- Science. 22 July im\ .570-74,

IU. {•or a liiller examination of lhe ctTccts of ozonepollution ami policv challenges lo combal it. see M.Bemsiein antJ D, Whitman, "Smog Alert: The Challengesof Buiiling O/.one Polhilion," in tbis issue {Envinmment.

ENVIRONMENTarticles in your courses

Visit www.heldref.organd click on "Archives"

October 2005). pages 28-41.1 i. J, Kaiser and M. Enserik. 'Treaty Takes a POP at

the Diny Do^êii." Science. 15 Deeember 20(XJ. 2053.

12, Intergovemmenial Panel on Climaie Change(IPCC), Clinuilc Change 2001: Synthesis Rqi-n: Thin!A.i.ses.wieiii RejHirt of the Imergovernmental Paiwt tmClimaie Change (Cambridge. UK. and New York: Cam-bridge University Press, 2()OI), See, in particular, page 5.

13, J. R, MvNci]]. Something New Under the Sm: AnEnvinmmentid History nf lhe TWeiitieih-Ceniiiry World(New York: W.W. Norton. 2000).

14, R. W, Kaics and T. M. Parris. "Long-Tenn Ti ;ndsand a Sustainability Traiisiiion." Procei'dings of theNaiiiiiral .Academy of Science.'^ of the United Stales ofAmerica 100. no, 14 '(2(K)3): 8062-67.

15, National Researeh Couneil. Board on Sustain-able Developmeni, Our Common Journey: A Tramitiimlow'iird Sitstainahiliiy (Washington. DC: National Acad-emy Press, 1999). 20,

16, J. E, Hansen. "A Slippery Slope: How MuehGlohal Warming Consiiluies 'Dangerous Anthropogeniciniert'erenee''.'" Climalir Chwige 68. no. 3 (2t)O5|: 269-79; and M, Oppenheimer and R. B. Alley, 'Tlie WestAniarciie Ice Sheei and Long Term Climate Poliey."Climatic Change 64. no, I - : (2(XH): 1,-iO,

17, J, Hansen. "Defusing lhe Glohal Warming TimeBoinb," Scienrijic American. Mureh 2004. 68-77.

18, See. for example, M. F, Loutre and A. Berger."Future Climatic Changes: .\re We Emering An Excep-lionally Long inlerglaciar,'" Climatic Change 4fi. no. 1-2(2(H)0i: 61-90, Noic ihat the "natural" elimate develop-meni is laijici) deieniiineii by lhe Milankovich mecha-nism, thai is, the q u asi-period ie varialion of planetaryinsulation as govemeiJ by tbe laws of astrophysics,

19, H, J, Schellnhuher, nole 1 above. CI9; H, J,Schellnhuber and V, Wenzel, Earth Sy.stem Analy.iis:Integrating Science for Sustainohility (Berlin: Springer.IWK): and H, J, Schellnhuber and D, Saliagian. 'TheTwcnly-Three GAIM Questions." Glohul Change New.i-leuer. April 2002. 20,

20, Tlie Dahlem Conferences are a special-formalworkshop series, dedieated lo the most advanced frontiersol' interdi.sciplinary science and named after iheir iradi-tional venue, a district of Berlin.

21, H. J. Schellnhuber. P. J. Cruizen, W. C. Clark.M, Claussen, and H, Held. cds,. Earth Sysicm Analysisfor SiistoinuhiUiy: Repmi un the 91" Oiihlem Workshup(Cambridge, MA. and Ltmdon: The MIT Press in ctxjp-eration with Dahlem Universiiy Press, 2(X)4),

22, See. I'or example, J. Lovelock, Tlie Agei of Gaia:A Biography of Our Living Earlh (Oxford: OxfordUniversiiy IVess, 2000), Envimnment published a vividdebaie of tbe Gaia tbeory in its May 1990 issue. See S,H, Schneider. "Debating Gaia," Envinmmeni, May 1990,4-9. 29-32.

23, For a thorough discussion of ihis mailer, see T, M,Lenion, el al.. "Group Report: Long-ienii Geosphere-BU>sphere Coeveoiuiion and .Asuvtbiolagy." in Scbellnhuber.Crui/en, Claik. Claussen, and Held, note 21 above, pages111-40, A siyli/ed summary of ihat discussion is givenin T M, Lemon, H. J, Sebellnhuber, and E. Sieathmdry."Climbing tiie Co-evolution Ladder," Nalurv, 21 October2004.913,

24, A. J, Watson, eial,, "Group Rcpoii: Possible Slatesand Modes ol'Operation of the Quuiemary Hunh Sysiem."in Schellnbuber. Cnit/en, Clark, Clau.ssen, and Held, note21 abtive, pages 189-210,

25, A promising approach employs Eanh Systemmodels of intermediale complexity (EMICsl like lheCLIMBHR family operated at lhe Poisdam Insiiiuie,For an inlercsiing recent resuil. see G, H. Haug el al,.'"N{inh Paeifie Seasonably and lhe Glaciaiion of NortbAmerica 2,7 Million Years Ago," Ncitinv. 24 February2005,821-25.

26, See also W, Steffen ei al,. "Abi-uiH Changes: TheAehilles" Heels of ihe Eanh System." Environment. April2004, 8-20.

27. K, Zickfeld B, Knopf. V, Peloukhov, and H, J,Schellnhuher, "Is tbe Indian Summer Monsixiri St;ihleagainsi Global Change',*" Cenphy.wa! Re.ieanh iîters32.no, 1512005): LI57O7.

28. A lull account of this londmaric meeting will begiven in H, J, Sehellnhuber ei al., eds., Auiiding Ottn-gen>u.-^ Clitnive Change (Cambridge, LIK: CambridgeUniversiiy Press, fonhcoming 2005).

29, K. Caldeira and M. E. Wickeii, "Oceanography:Anihropogcnie Carbon and Oeean pH," Nature. 25 Sep-leniber 2(W3. 365,

30, See. for insumce. T, RadfonJL "Huge Rise in Sibe-rian Forest Fires Puis Planet at Risk, Scientists Wam,"The Guardian. 31 May 2005, 2,

.31, Note ihai lax laws are likely lo aggravate Iheproblem, sinee many fires in Siberia appear to bavcbeen sei by arsonists for creating more salvage limberas reponed by BBC News. "Rre Threal to Siberia'sForests," BBC News Online. 31 May 2005, http://news.bbc.eo.uk/2/lii/eurt>pe/4596651 ,sini.

32. A, Sen, Inequality Reexumincd (Oxford: OxfordUniversity Press. 1995),

3.1. See, for example. Uniied Nations Secreiarv-General. In Larger Freedom: TouurdM Development.Security and Human Rights for All: Report of theSecretary General w lhe UN General .Assembly. 21March 2005, bllp://wwwûn,org/]aIg[erfreedom/: and C,Narbona Rui/. S. Lepellier. and J, Trillin, "Die Unuvellmuss in den Mittelpunkl" ("The Environment Musi 'HikeCenter Stage"). Erankfurter Rundschau. 11 May 2()()5. 7,

34, Wissenschaltl idler Beiral dei' BundesregierungGlobale Umwellveriuiderungen (WBGU) (German Advi-sory Couneil on Global Change], World in Transiiiim:Nay Struciures for Global Envinmmental Policy (Londonand Sierling, VA: F-anhsean. 2001).

.15, UN Millennium Project. Investing in Develop-ment: A Practical Plan to Achieve the Millennium Devel-opment Goals: UN Millennium Project. Re/iort to the UNSevrvtary-General (New York: Uniied Nations, 2005),bt tp •Jlwvivi. unmi I lenni umprojecl, org/,

36. Nine ihai a revival of the "Rio spirii" musi havemajor inslilulional impliealions, sueh as the replaeememof llie increasingly inadequate L'N Economic and SoeialCouncil (ECOSOC) by a "Council for Global Develop-ment and Environment." (See WBGU, World in Tnm.si-tiiin: Fighting Poveny ihrcmgh Euvinmrnental Policy(London: Earlhscan. forthcoming 2005.)

.17, In lhe summer ol' 2003. a lolal of 20.000-30,000people died in Europe—mainly in ilie big cities andpanicularly lhe elderly and vulnerable—a.s a rcsull ol'extremely liigli tempemmres. See R, S. Kovais. T, Wolf,and B. Menne, "Heatwave of August 2(K)3 in Eumpe:Provisional Hstimaies of lhe lmp;icl on Monaliiy." fcimi-.•iur\<edlance Weekly. II March 2004, W-K much highertempcraiures are likely to become siandard in .' sian eitiesin lhe wake of climaie change.

38, For instance, on 5 June 2(X).'i. inayor ; Imni ;iroundlhe world signed lhe Urtvan Environmental Accords,See Uniied Naiions World Environmeni Day 2(X)5 newsrelease, "Mayors Sign Historie Environnienial Aceords,"hlip://www,wed2(X)5.org/5,l,pbp,'news_id=3(),

39, The Royal Soeieiy. Ocean Acidifu-aiimi Due toIncreasing Atnvispheric Carbon Dioxide, policy docu-ment 12/05 (London: The Royal Society. 2lX)5).

40, A. Jolly. "The Fifih Step." Ne\*' Scienti.it. 25Deeember 1999,78-79,

41, S. H, Schneider. "Geoengineering: Could—orSbould—We IX> 11?" Climatic Change 33, no, 3 (1996):291-.102.

42, K. S, Lackner. "A Guide to Ct.), Sequestration,"Science. 13 June 2003, 1677-78,

43, P. i. Cnil/.en, "Towards a Global Experiment onClimaie Conmil?" Climatic Change. fortbe<iming 2005,

44, Schellnhuber, note 1 above, page C19: and W,Lueht and R, K, Pacbauri, "The Mental Componentof lhe Eanb System," in Schellnhul->er. Cnii/en. Clark.Claussen, and Heltl, nole 21 above.


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