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CLIMATE HISTORY. MiltBrown, South Carolina stateclimatologist, leans on books ofweather-station observationsdating to the late nineteenthcentury. Brown worries thatdiscrepancies in differentgenerations of temperatureinstruments have caused variationsin weather data during the past 30years. “Different little things canaffect the reliability of weatherobservations, and we need to getthe best weather records we can.”PHOTO/WADE SPEES

HOTHOUSE PLANETSome wild creatures could be lost in climate change’s wake.

MOMENTUM CHANGENearly all experts agree that humans have a strong hand in causing recent global climate change.

EBBS AND FLOWS

ON THE COVERThe Earth, fortunately, is a hothouse planet, benefiting from the greenhouse effect. Greenhouse

gases naturally reflect a portion of the sun’s solar radiation back to the Earth, warming theplanet’s surface and atmosphere like a greenhouse’s windows contain heat. But now pollution,

scientists say, is increasing the greenhouse effect, driving the planet’s average temperature higher.PHOTO/WADE SPEES

Coastal Heritage is a quarterly publicationof the S.C. Sea Grant Consortium, a university-based network supporting research, education,and outreach to conserve coastal resources andenhance economic opportunity for the people

of South Carolina. Comments regarding this orfuture issues of Coastal Heritage are welcomed.

Subscriptions are free upon requestby contacting:

S.C. Sea Grant Consortium287 Meeting Street

Charleston, S.C. 29401phone: (843) 727-2078

e-mail: Annette.Dunmeyer@scseagrant.org

Executive DirectorM. Richard DeVoe

Director of CommunicationsLinda Blackwell

EditorJohn H. Tibbetts

Art DirectorPatty Snow

Contributing WriterSusan Ferris

�Board of Directors

The Consortium’s Board of Directors iscomposed of the chief executive officers

of its member institutions:

Dr. Ronald R. Ingle, ChairPresident, Coastal Carolina University

James F. BarkerPresident, Clemson University

John E. FramptonExecutive Director

S.C. Department of Natural Resources

Dr. Raymond GreenbergPresident, Medical University of South Carolina

Major General John S. GrinaldsPresident, The Citadel

Leo I. Higdon, Jr.President, College of Charleston

Dr. Andrew H. Hugine, Jr.President, S.C. State University

Dr. Andrew SorensenPresident, University of South Carolina

CONTENTS3

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COPYRIGHT © 2003 by the South Carolina Sea Grant Consortium. All rights reserved.

SUMMER 2003 • 3

SPRING ARRIVES. The tree swallow (Tachycineta bicolor) is among hundreds of wild species shifting behavior in response to climate change.PHOTO/PETER LaTOURETTE

By John H. Tibbetts

Signals of a warming planet can be read in thebehavior of a common little bird. Only five incheslong, the tree swallow (Tachycineta bicolor) is a

migratory songbird with iridescent blue-green wings and agleaming white belly. This small creature is a highlysensitive climate-change indicator across a band of temper-ate North America, from New England to the PacificNorthwest. By studying the tree swallow’s nesting patterns,researchers have discovered that spring warming now arrivesmore than a week earlier in places like Massachusetts andWisconsin because of global climate change.

Tree swallows, agile and swift, winter in places likecoastal South Carolina, roosting in huge numbers inwax-myrtle trees and wheeling across the sky in pursuit offlying insects.

Then in early April they migrate north to claim anddefend nesting sites in tree cavities and bird boxes. Apriltruly is the cruelest month for these birds. Tree swallowsmust survive the last freezing weeks of northern winter untilflying insects emerge during the first or second week of May.

“They have some really lean times,” says Cornell Universityecologist and evolutionary biologist David W. Winkler.

The birds fatten up when insects start flying again. Buttree swallows are patient family budgeters. Only when theycan catch enough insects do they start laying eggs. Treeswallows time their breeding to the moment when insectpopulations explode in abundance, occurring during thefirst vigorous spurt of northern warming. Thus, if you studywhen these birds lay eggs, you’ll know when spring arrivesacross the forested regions of the continent’s northern tier.

Over a period of four decades, volunteer bird watcherstracked about 21,000 tree-swallow nests in the UnitedStates and Canada, sending data cards to CornellUniversity’s Laboratory of Ornithology. With this informa-tion, Winkler and colleagues learned that tree swallowswere laying eggs nine days earlier on average in 1991 thanthey had in 1959. The birds, Winkler says, are respondingto global warming and earlier spring temperatures. Thisstudy, however, does not address nesting data throughoutthe 1990s, the warmest decade in recorded history.

HOTHOUSE PLANETWhich wild creatures can adapt to accelerating climate change?

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Dozens of bird species withvarious life histories are similarlynesting earlier than before. And “a lotof bird species—from short-term tolong-term migrants—are going northone to three weeks earlier than theydid 20 years ago,” says Jeff T. Price,director of Climate Change ImpactStudies at the American Bird Conser-vancy, based in Boulder, Colorado.“Very few species are migrating later.”

Plants are flowering sooner thanthey did a few decades ago in manyregions. Some mammals are breakinghibernation earlier. Many species haveshifted their ranges toward the poles.

The Earth has warmed by 1.1degrees Fahrenheit since 1900, anunprecedented temperature rise overthe past millennium. Two-thirds ofthis warming has occurred just withinthe past 30 years, including an abrupttemperature spike upward starting inthe mid-1990s.

Over the past several decades,hundreds of research projects havedocumented wildlife species’ re-sponses to global warming. Workingindependently, two research teamsanalyzed many of these previouslypublished papers, offering a startlingpicture of a changing climate’simpacts on wild creatures.

Terry L. Root, a Stanford Univer-sity ecologist, and colleagues usedstatistical tools to analyze 143

separate research studies involving atotal of 1,473 species of plants andanimals. Each original study examined acorrelation between climate change anda biological response in plants oranimals somewhere in the world.

More than 80 percent of species hadmade a temperature-related shift inresponse to climate change, Root and co-authors discovered. Spring events—migrating, blooming, and nesting—hadshifted earlier by an average of five daysper decade over the past 30 years fortemperate-zone species.

In another study, Camille Parmesan,a biologist at the University of Texas atAustin, collaborated with WesleyanUniversity economist Gary Yohe toanalyze studies of 172 species of plants,birds, butterflies, and amphibians. Springevents had advanced by a mean of 2.3days per decade over a time period of 16to 132 years, with a median of 45 years.

Terrestrial ecosystems have experi-enced greater warming than deepoceans. But marine creatures are movingpoleward too, particularly in intertidalareas and along continental shelves;shallow water is affected more bytemperature than deeper ocean water.Around California’s Monterey Bay,warmer water has changed communitystructure, driving many invertebratesnorthward and out of the bay, andallowing other species to replace themfrom the south.

The Greenhouse Effect

Solar radiationpasses through theclear atmosphere.

The Earth andatmosphere reflectsome solar radiation.

Greenhouse-gas molecules absorband re-emit infrared radiation, causingwarming of the Earth’s surface andthe lower atmosphere.

Compounding problems

Climate change is not today’s mostimportant environmental crisis, somesay. The potential consequences ofglobal warming, they argue, are too farin the future to worry about. Instead,society should concentrate onoverpopulation, suburban sprawl,excess nutrient pollution, invasivespecies, and water overexploitation.

The reality, however, is that globalwarming already worsens manychallenging environmental problems.“It’s the combination of population,resource use, and climate change thatreally makes the nasty brew,” saysJames White, a climate scientist at theUniversity of Colorado.

Rapidly growing populations andagriculture are using vast amounts ofwater, driving down reservoir levelsand aquifers in some regions, evenduring times of average local rainfall.Society therefore often creates“human-demand droughts” in absenceof meteorological droughts.

To compound this problem, globalwarming is apparently spawningincreasing meteorological droughts insome regions, climate scientists say.

Starting in the late 1990s, anextremely intense warming in thewestern Pacific associated with theLa Nina phenomenon pumpedadditional heat into the atmosphereand altered winds of the jet stream,changing precipitation patterns in aband stretching nearly around theworld, including much of NorthAmerica, from 1998 to 2002, reportsMartin Hoerling of NOAA’s ClimateDiagnostics Center and Arun Kumar ofNOAA’s Climate Prediction Center in arecent Science journal article. TheU.S. Southeast was one of the areashardest hit by this drought.

The hot-temperature spike in thewestern Pacific was partly due toglobal warming consistent withincreasing greenhouse gases, theresearchers noted in their article.

Some meteorological droughts inthe United States and elsewhere mayhave man’s thumbprints all over them.“That human-contributed greenhousegases could be causing widespread,persistent, and very damagingdroughts raises the stakes consider-ably,” says White.

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In the North Atlantic Ocean,five of eight commercially importantgroundfish species have moved northin response to warming. Growingnumbers of fish species common toCaribbean waters have been found ata reef off Beaufort, North Carolina,over the past 25 years. “The reefpopulation here is much moretropical than it was,” says R.O.Parker, a research fishery biologistwith the NOAA National MarineFisheries Service in Beaufort.

Just as wild creatures respond toa rapidly changing climate, so do rowcrops, forest plantations, and disease-carrying insects. Global warming islikely to affect many ecosystems onwhich we depend.

The Earth’s average surfacetemperature will continue growinghotter over the next half-century atleast. Natural variation has a part inthis change. But human actions,scientists say, are mostly to blame.We are burning so much carbononce stored in the Earth—oil,natural gas, and coal—that we arealtering the world’s climate.

Since the industrial revolutionbegan 200 years ago in Europe,people have burned fossil fuels,increasing the amount of carbondioxide and other so-called “green-house” gases sent into the Earth’satmosphere.

The “greenhouse effect,” ofcourse, is a natural phenomenon.Greenhouse gases—carbon dioxide,methane, and nitrous oxide—naturally reflect a portion of thesun’s solar radiation back to Earthand warm the planet. This entrap-ment sustains the global surfacetemperature. Without the green-house effect, the planet would be aball of ice.

The problem is that our fossil-fuel burning increases the greenhouseeffect, trapping more of the sun’senergy and causing the Earth’stemperature to rise.

“When we use the atmosphereas a sewer, something happens,” says

Stephen H. Schneider, a professorof geosciences at StanfordUniversity.

In 1988, the nations of theworld appointed the Intergovern-mental Panel on Climate Change(IPCC), comprising more than2,000 leading experts to assess thescience and economics of climatechange. In 2001, the IPCCpublished its third major report,forecasting that the Earth couldwarm by 2.5 to 10.4 degreesFahrenheit by 2100.

Global climate changegenerally affects higher latitudes(colder places closer to the poles)more than subtropical andtropical regions. In Alaska, forexample, average temperatureshave risen by about 3.6 degreesFahrenheit over the past 30 years.

“There is not uniformwarming” around the world, saysJames White, a climate scientist at

the University of Colorado. “Europeand Asia are warming up quite a bitfaster and quite a bit more (in degree)than North America.” Indeed, theentire U.S. Southeast has actuallycooled very slightly over the pastcentury, though South Carolina haswarmed by about 1 degree Fahrenheit.

The Arctic and Antarctic haveexperienced the most abrupt climatechange. Since the 1950s, higher polartemperatures have diminished theextent of Arctic sea ice by 30 percentin spring and summer. Now floatingmasses of sea ice are splitting apart.The massive Greenland ice capmelted more last summer than inrecorded history.

Unless nations support swift,substantial cuts in greenhouse-gasemissions, Arctic sea ice in summertime could diminish 60 percent by2050, according to a 2001 assessmentby the United Nations EnvironmentProgramme. Melting of polar ice and

SKETCHING THE PAST. The upper curve shows atmospheric carbon dioxide over thepast 160,000 years. The lower curve shows temperature variation over the same period. Datafor these figures were taken from ice cores at Vostok, Antarctica. Data for this chart stop longbefore the industrial era began in 1750. Notice the correlation between carbon dioxide andtemperature. Source: Wolfson, Richard and Stephen H. Schneider. “Understanding ClimateScience.” In Climate Change Policy: A Survey. Washington, DC: Island Press, 2002.

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permafrost pushes more freshwaterinto the Arctic Ocean, whichcould stimulate explosive shifts inocean circulation and climatearound the world.

How high could tempera-tures go, and how quickly?

“That increasing greenhousegas concentrations contributed to(global) warming is not in seriousdispute,” notes a 2001 report bythe George C. Marshall Institute,a nonprofit organization knownfor its criticism of mainstreamclimate-change research.

Skeptics argue that globalwarming is not cause for alarm.More warming has alreadybrought some positive effects,they say. Since the 1960s,growing seasons have lengthenedby one to four days per decade inthe Northern Hemisphere,particularly in higher latitudes.Some cold-weather places nowhave more warm days to grow

crops, and people have lowerheating bills in winter. Mostpeople in industrial nations,skeptics say, would simply adjust toa changing climate.

Patrick Michaels, a Virginiastate climatologist and well-knownglobal-warming contrarian, hasargued that the planet will likelyheat up by 2.8 degrees Fahrenheit bythe year 2100. His forecast fallswithin the lower range of the IPCCassessment, yet it is almost triple theamount of last century’s warming.

But even modest globalwarming could spell doom forcreatures in certain vulnerablehabitats. Within 50 years, somesmall oceanic islands could bedrowned by large storms and risingsea levels. By 2050, coastal wet-lands and mangroves in someregions could be permanentlysubmerged. Many species innorthern intertidal zones will facelocalized extinctions because of

heat stress. Many coral reefs worldwideprobably will be gone, killed bywarming water and other impacts.

“Some ecosystems will find itvirtually impossible to adapt to a fairamount of climate change, no matterhow slowly it arrives,” says Thomas E.Lovejoy, president of the HeinzCenter for Science, Economics, andthe Environment, based in Washing-ton, D.C.

Mountaintop glaciers in warm-weather countries almost certainly willmelt rapidly. High-altitude ice and snowin places like Tanzania have alreadyreceded so quickly that they will be gonein just 20 more years, says Lovejoy.

Go see them while you can: thefamous snows of Kilimanjaro will soonbe no more.

HISTORIC EVIDENCE ANDMODELS

How do scientists really know thatthe Earth’s surface is warming?

Beginning in the mid-1850s,governments established a network ofinstruments that have measured surfacetemperatures across land and marineregions of the Northern Hemisphere.As a result, researchers have continuousdocumentation of the hemisphere’sclimate over the past 140 years.

Two-thirds of recorded globalsurface warming has occurred since theend of the Vietnam War, and thedecade of 1990s included nine of the 10hottest years since the Civil War began.The warmest year was 1998; the thirdand fourth hottest were 1990 and 1995.The twenty-first century got off to ablazing start in 2001 and 2002; thelatter was the second warmest yearon record.

“We are reaching a fundamentallydifferent level of temperature changeon the planet,” says White.

The Earth’s biological andphysical “archives” also contain cluesto ancient temperatures. Bubbles of airtrapped in Antarctic ice show that forthe past 400,000 years carbon-dioxidelevels in the atmosphere have closely

WHAT YOU CAN DO

You can take steps to reduce energy consumptionand fight global climate change.

Your action: CO2 reduction (pounds per year)

1. Use a push mower instead of a power mower: 80 (pounds peryear)

2. Install low-flow showerheads to use less hot water: 300

3. Replace your washing machine with low-energy, lower-water-usemachine: 440

4. Keep your hot-water thermostat no higher than 120° Fahrenheit:500

5. Recycle all of your home’s waste newsprint, cardboard, glass, andmetal: 850

6. Caulk and weatherstrip around doors and windows to plug upleaks: 1,000

7. Leave your car at home two days a week (walk, bike, take publictransit): 1,590

8. Insulate walls and ceilings: 2,000

9. Purchase a fuel-efficient car (rated at 32 mpg or more) to replaceyour most frequently used automobile: 5,600

10. When replacing windows, install energy-saving models: 10,000

Source: Environmental Protection Agency

SUMMER 2003 • 7

followed global temperatures asrevealed in ice cores. It seems clearthat carbon-dioxide levels andtemperature generally move inlong-term tandem.

By studying tree rings and icecores, researchers have concludedthat recent surface temperatures areprobably higher than any compa-rable era since the Middle Ages.The period from 1970 to 2000 waslikely the Northern Hemisphere’swarmest three-decade period of thepast thousand years, according tothe Climatic Research Unit at theUniversity of East Anglia inGreat Britain.

Global average temperaturewill continue to rise because ofheat-trapping pollution, climatescientists agree. Cars, factories, andpower plants emit about 24 billiontons of carbon dioxide a year.Forests and the ocean, which helpsoak up heat-trapping gases, cannotabsorb swiftly rising emissionslevels. Instead, the atmosphere willhave to take up more of thegreenhouse-gas load.

Pollution from cars andfactories does not affect climateimmediately. It takes 10 to 20 yearsfor today’s pollution to beginshowing in the temperature record.But some greenhouse gases havelong lives. A century from now,our descendants will likely experi-ence rising temperatures caused bycurrent pollution.

WHAT’S THE CAUSE?

Could the recent spike inglobal surface temperature andArctic meltdown be attributed to anatural, cyclical phenomenon?

Numerous forces affect globalclimate change, including solarvariability that nudges Earth’stemperatures up or down, volcanicexplosions that spew dust intothe air and cool the planet, andgreenhouses gases that warmthe Earth.

But only one phenomenon, mostclimate scientists say, can satisfacto-rily explain the sudden globaltemperature jump at the end of thetwentieth century. “The recentwarming, particularly over the past20 years, cannot be attributed toanything but human involvement ingreenhouse gases,” says White.

Scientists use general-circula-tion computer models to estimatehow the climate will respond toincreasing greenhouse gases. Thesemodels—which Schneider calls“mathematical expressions ofphysical laws that we believe in”—are extraordinarily complex, withmany built-in uncertainties.

Early models could not begin toapproximate the climate system’sintricacy. But newer models incorpo-rate more of the hydrological,geological, and biological factors thatinfluence climate: dust and soot,volcanoes, tree cover, ocean currents,among many others.

Yet even the best models cannotaddress factors that will dramatically

affect the pace of future warming,such as the behavior of water vapor,clouds, and atmospheric particles.These “feedback” mechanisms couldsignificantly increase warming ordamp it down.

The problem is that nearly allfeedback mechanisms in currentmodels are positive, skeptics say.Computer models show that as theEarth grows warmer, the atmosphereincreasingly traps energy from thesun. As a result, the Earth’s atmo-sphere becomes moister, whichexacerbates surface warming, whichmakes the atmosphere even moister.

Nevertheless, the Earth’s climateprobably doesn’t work like that, saysJohn Christy, an Alabama stateclimatologist and an IPCC reportlead author. As human societyincreases greenhouse-gas emissions,larger-than-expected amounts ofenergy apparently leak into spacefrom the Earth’s surface, thereforeslowing global warming.

“There is increasing evidencethat energy escapes (from the Earth’s

Reading

George C. Marshall Institute. Climate Change and Policy: Making the Connection.Washington, D.C., 2001.

Hoerling, Martin and Arun Kumar. “The Perfect Ocean for Drought.” Science, January31, 2003.

Intergovernmental Panel on Climate Change (IPCC). Climate Change 2001: SynthesisReport. A Contribution of Working Groups I, II, and III to the Third Assessment Reportof the IPCC. New York: Cambridge University Press.

Kennedy, Donald. “The Policy Drought on Climate Change.” Editorial. Science,January 17, 2003.

Parker, R.O. Jr. and R.L. Dixon. “Reef Faunal Response to Warming in Middle U.S.Continental Shelf Waters.” In Proceedings of the Sea Grant Symposium Fisheries in aChanging Climate, August 20-21, 2001. McGinn, Nature A. (ed.) Bethesda, Maryland:American Fisheries Society, 2002.

Parmesan, Camille and Gary Yohe. “A Globally Coherent Fingerprint of ClimateChange Impacts across Natural Systems.” Nature, January 2, 2003.

Revkin, Andrew C. “Global Warming: All That Hot Air Must Be Having an Effect.” NewYork Times, January 12, 2003.

Root, Terry L. et al. “Fingerprints of Global Warming on Wild Animals and Plants.”Nature, January 2, 2003.

Winkler, David W. et al. “Predicting the Effects of Climate Change on Avian Life-History Traits.” Proceedings of the National Academy of Sciences, October 15, 2002.

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surface into space) through clear,dry areas of the planet,” saysChristy. “Those areas become drierand larger as (atmospheric) carbondioxide increases.”

This process, he says, is part ofthe planet’s self-regulatingmechanism, in which climatetends to return to the long-termmean after temporarily becomingcolder or warmer. Christy alsoargues that greenhouse-gasemissions can be blamed for only asmall fraction of global warmingover the past century.

But only a tiny minority ofknowledgeable scientists—just ahandful in number—holdsChristy’s view that human

society is not primarily respon-sible. The overwhelming majorityof climate scientists argue thathumankind is largely to blame forrising temperatures.

Even so, climate scientistsacknowledge their lack of anairtight case: they cannot provebeyond any doubt that increasinggreenhouse gases from humanactivities have warmed the Earthand will continue to do so.

Researchers, however, do have“multiple lines of evidence andfingerprints” that the planet haswarmed primarily because ofgreenhouse-gas emissions, Schneidersays. Climate scientists havegathered detailed circumstantial

evidence that human activities aremostly to blame for the rising averageglobal surface temperature.

Scientists are especially confidentthat they understand the workings ofcarbon dioxide, the most influentialheat-trapping greenhouse gas. Before1750, global carbon-dioxide load inthe atmosphere was 280 parts permillion. Due to increased pollution,the atmospheric load has risen to 370parts per million, one-third above pre-industrial levels.

The Earth’s atmosphere, accordingto climate-computer models, is likely tocontain double the pre-industrial levelsof heat-trapping gases within the next50 years, causing a rise of two to fourdegrees Fahrenheit in global average

SUMMER 2003 • 9

surface temperature. Unless theglobal community establishespolicies to control greenhouse gases,the atmospheric load could rise to1,000 parts per million by the end ofthe next century, causing potentiallyexplosive climate changes.

Climate scientists haveassumed that increased economicdevelopment, particularly indeveloping countries, would causesharply rising greenhouse-gasemissions. New, cleaner technolo-gies cannot quickly replace pollut-ing energy sources such as coal-firedelectric plants and the internal-combustion engine.

But that assumption is wrong,says Michaels. Instead, developing

countries will soon bypass older,dirty technologies and employtechnologies that reduce heat-trapping emissions. “Very cleantechnologies are being developed byaffluent countries,” says Michaels,“and these technologies are going tobe sold to developing countries.”

Still, an important questionremains: should governments waitto act until researchers havecomplete scientific certainty beforetaking steps to control greenhouse-gas pollutants? No, climate scien-tists say. By the time researchershave “smoking-gun” evidence, itcould be too late to preventenvironmental, social, and eco-nomic catastrophes in some regions.

BIOLOGICAL IMPACTS

Animals have always responded totemperature fluctuations throughouttheir evolutionary history. Couldn’tmost creatures adjust to climatechange? Isn’t that what naturalselection is all about?

Climate change hasn’t harmed thetree swallow, which nests earlierwithout ill effects. The tree swallowstill thrives by eating flying insects.And it could probably adapt to climatechange over the next century. “Treeswallows should do pretty well,” saysWinkler, because flying insects wouldstill provide a consistent food source ina hotter era.

But other species might not be sofortunate.

Plant and animal species thriveonly within certain temperatureranges. They must relocate to a newhabitat when a particular location getstoo hot or too cold for them. Whenthe climate cools, species generallymove in the direction of the Equatorand down mountainsides. When theclimate warms, most species headtoward the North Pole in the North-ern Hemisphere and the South Pole inthe Southern Hemisphere, or theymove up mountainsides.

In the future, some species couldrelocate to habitat many miles away,though their food sources might notfollow as far. Meaning that an animalspecies might relocate to a differentplace than its prey does. “We could see

NIGHT LIFE. This is a composite image ofhundreds of pictures made by orbiting defensesatellites, illustrating what the Earth looks like atnight. Urbanization has spread to nearly everyhabitable corner of the world. “There’s nothingon the planet that people don’t monkey with,”says climate scientist James White of theUniversity of Colorado-Boulder.PHOTO CREDIT/C. MAYHEW & R. SIMMON (NASA/GSFC), NOAA/ NGDC, DMSP Digital Archive

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a tearing apart of natural communi-ties,” separating animals from theirfood sources, says Root.

Some animals with narrowforaging requirements might notsurvive in a rapidly warming world.A bird, for example, that reliesexclusively on a particular species ofinsect or worm could starve or failto reproduce. The bird’s climate-induced migration could be out ofsynchrony with its prey’s migration;predator and prey could go todifferent places.

“Those species with any kindof specialized relationship with preyorganisms could really get intotrouble,” says Winkler.

Moreover, cities, farms,ranches, plantation forests, andother intensively managed land-scapes could block many climate-induced wildlife migrations. Speciescould get squeezed between risingtemperatures behind them anddevelopment in front of them.Thus, rapid climate change couldcause numerous extinctions.

Higher temperatures wouldlikely spawn faster rates of evapora-tion and precipitation, so that

some regions would have shorter andmore intense rainy seasons. Otherregions would have longer droughts,endangering some crops and causing adrop in global food production,though most U.S. agricultural sectorscould adapt to a warmer climate.Longer droughts would also diminishwater supplies in many areas, exacer-bating existing shortages.

Mosquitoes and many otherdisease carriers will probably increasetheir range due to warmer and wetterweather. Illnesses such as malaria anddengue fever will probably becomeeven more prevalent in some develop-ing nations. “A warmer world wouldbe a sicker world,” says Andrew P.Dobson, an epidemiologist andecologist at Princeton University.

PLANETARY MONKEYING

Some experts had hoped that theKyoto Protocol of 1997 would be theanswer to global climate change. It isan international treaty that seeks tocontrol greenhouse-gas emissions tobelow 1990 levels by 2012, applyingmandatory standards on advancedindustrial nations that ratified it. The

problem is that the Kyoto’s provisionswould only amount to a two to fivepercent cut in greenhouse-gas emis-sions. “Kyoto really does little tomaterially affect the climate,” saysRoger A. Pielke, Jr., a University ofColorado political scientist. The Kyototreaty is far too little, too late, he says.

President George W. Bushannounced in 2001 that the UnitedStates would not ratify the Kyototreaty two years after the U.S. Senatedeclared it dead. The U.S. governmentsaw Kyoto as unfeasible, because mostof its costs would have fallen on theshoulders of American companies.Instead, the Bush Administration hassought voluntary commitments fromcompanies to reduce emissions, arguingthat the science addressing climatechange is uncertain and that humanfactors are not clearly contributing toglobal warming.

This stance sparked internationalcriticism from U.S. economic partnersthat point out that the United Statesproduces about 25 percent of theworld’s carbon-dioxide emissions.Japan and Australia together produceabout 6 percent; all of Western Europeproduces 16 percent.

LEADER OF THE PACK. The United States is blessed with the largest economy on Earth, but it is also the largest contributor toworldwide greenhouse-gas emissions. China produces the second-largest amount of greenhouse-gas emmissions, while Japan has thesecond-largest economy.

Source: EPA 1998 Source: World Bank 2002

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CLEAR WINNER. One of theeasiest ways to cut energy use andfight global climate change is toreplace older windows with energy-saving models and install high-performance models in newconstruction. PHOTO/WADE SPEES

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Intergovernmental Panel on Climate Change: www.ipcc.ch

World Meteorological Association: www.wmo.ch/indexflash.html

EPA Global Warming site:yosemite.epa.gov/oar/globalwarming.nsf/content/index.html

Grist Magazine “Heat Beat”:www.gristmagazine.com/heatbeat/thisjustin013103.asp

Web sites

Sea levels

Could climate change interact with anatural cycle in sea level to damage coastalresources?

During the past century, sea levels haverisen by an average of one foot on Gulf andAtlantic beaches primarily because ofseawater’s thermal expansion. When theglobal surface temperature becomes hotter,seawater expands, and sea levels rise.

Shorelines have migrated landward at anaverage rate of one or two feet per yearover the past century, though localconditions vary greatly. In some areas, theannual erosion rate is more than 20 feetannually. Other areas are stable or growing.

Sea levels are expected to rise by anaverage of 19 inches worldwide between1990 and 2100, affecting low-lyingcountries and some coastal cities andhabitats, according to the World WaterCouncil, an international water agency.

Sea level also naturally fluctuates duringcycles on the order of every 20 years, saysJames T. Morris, a marine biologist at theUniversity of South Carolina. For a single20-year period, sea level rises overall,though there are ups and downs within thelarger cycle. Then for the next 20-year cycle,sea level falls overall, though with smallerups and downs. “The 20-year cycles areregular and very predictable, but they arenot caused by any astronomical force thatwe know of, such as the motion of theplanets, moon, and sun.” These cyclesremain a mystery, says Morris.

Today, sea levels have neared the verytop of a natural cycle. “Sea level has risenvery rapidly over the last 10 to 15 years,and we are now due for a decline in sealevel over the next decade, provided pastcycles repeat themselves. The fact that wedo not understand their cause means thatwe cannot forecast with confidence.”

How much of recent sea level rise isdriven by the 20-year cycle and how much isdriven by global climate change? That’simpossible to say.

The ascending side of the 20-year cyclecould end soon. Sea level is likely to fallover the next two decades, reducing globalwarming’s impacts on coastlines. But in thefuture, an ascending swing of the 20-yearcycle could combine with thermal expansionof seawater to swamp coastal habitatsaround the world.

Many traditional U.S. allies haveargued for strong steps to controlgreenhouse gases. Prime Minister TonyBlair of Great Britain recently laid outambitious plans to cut greenhouseemissions by 60 percent in the nextfive decades.

Senators John McCain (R-Arizona) and Joseph I. Lieberman (D-Connecticut) have joined in proposinglegislation that would require manda-tory though small reductions ingreenhouse emissions by 2010 andsharper ones by 2016.

More than any other nation, theUnited States has the potential todisrupt the world’s climate. Yet thiscountry could adapt better than most.Americans have the scientific skills,financial resources, technology, andsocial and political structures to adjustto all but the most extreme scenariosover the next century.

American agriculture, for example,probably would not be harmed overallby climate change; in fact, warmingcould even help farmers in someregions. In the Southeast U.S., how-ever, climate change could spell troublefor many farmers and foresters. Agricul-ture is already a marginal activity in thisregion, and farmers would face in-creased water shortages for irrigation,potentially driving them out of busi-ness. Forests would likely endure greaternumbers of destructive pests and slowergrowth because heat stress couldweaken trees, says Milt Brown, SouthCarolina state climatologist.

As sea levels rise, U.S. coastalcities could retreat or build seawalls,though that would be expensive.Public-health resources could bemobilized to fight emerging and re-emerging diseases spawned by awarmer climate.

Poor people in some developingnations, however, could face calami-ties if the climate continues to warmrapidly. “What’s not dangerous in theU.S. might be dangerous somewhereelse,” says Tom Wigley, a seniorscientist at the National Center forAtmospheric Research, based inBoulder, Colorado. Residents of flood-or drought-prone regions—such ascoastal Bangladesh, the African desertSahel region, and small oceanicislands—would likely have to relo-cate. “In some cases . . . we’veprobably gone beyond the state ofadaptation (to global climatechange),” Rajendra Pachauri, chair-man of the IPCC, has said.

Now the Earth’s climate system isundergoing changes exacerbated bypollution, experts say. Nevertheless,many Americans believe that wecould not disrupt something as vast asthe Earth’s climate, and that naturalvariability must be solely to blame.

“The average person,” says White,“does not have a good grasp of just howimportant human beings are—not onlyin the climate system but in all phasesof the planet’s systems. There’s nothingon this planet that people don’tmonkey with.”

SUMMER 2003 • 13

Since the early 1990s, the momentum has shifted in scientific debates about global climate change. A decade ago,many researchers argued that global warming could be attributed exclusively to natural variation. Some doubted thatthe planet was warming at all. But the Earth’s surface is undoubtedly growing hotter, especially near the poles.

Moreover, a growing body of circumstantial evidence indicates that humans have a strong hand in this change.Experts are now more certain in answering one fundamental question over the past 12 years: are people contributing to

global warming?In 1990, the First Assessment Report of the Intergovernmental Panel of Climate Change (IPCC) reported: “The

unequivocal detection of the enhanced greenhouse effect from observations is not likely for a decade or more.”In 2001, the IPCC Third Assessment offered a firmer stand: “There is new and stronger evidence that most of the

warming observed over the last 50 years is attributable to human activities.”At the behest of President George W. Bush,

the National Academy of Sciences studied global-climate research and in 2001 issued a report thatsaid: “Greenhouse gases are accumulating in theEarth’s atmosphere as a result of human activities,causing surface air temperatures and subsurfaceocean temperatures to rise. . . . Human-inducedwarming and associated sea level rises are ex-pected to continue through the 21st century.”

Meanwhile, the two most influentialscience journals in the English-speaking world,Science and Nature, have published dozens ofstudies detailing the causes and impacts ofclimate change.

“The scientific evidence on global warming isnow beyond doubt,” Donald Kennedy, editor-in-chief of the journal Science, wrote in a recenteditorial. “Readers of these pages during the pastcouple of years have seen one careful study after another documenting the role of anthropogenic sources of carbon dioxideand other greenhouse gases in global warming; describing the impact of past and present climate change on marine andterrestrial ecosystems; and measuring rates of glacial melting in the Arctic, the Antarctic, and on the tops of low-latitudemountains.”

The United States, Kennedy argues, must takeaction on global climate change. “In this case, thestakes are well beyond national interest, becausethe nonparticipation of the United States in theglobal effort on climate change is more than anational embarrassment. It’s dangerous.”

To some skeptics, however, the editors ofScience and Nature have been blinded by politicalconsiderations. These journals “are agenda-drivenmagazines,” says John R. Christy, the Alabamastate climatologist and an IPCC report leadauthor. “They have decided that climate change isa threat; therefore it must be dealt with bycentrally planned solutions, taking access toenergy away from people, passing regulations froma government mandate, saying you must reduceyour energy consumption.”

Momentum change

STONE MOUNTAIN. A mountain of coal to be fired in a South Carolinapower plant. Electric power accounted for 39 percent of U.S. greenhouse-gasemissions in 2001. PHOTO/WADE SPEES

FILL ‘ER UP. Transportation—particularly cars, trucks, and jet fuel—accounted for about one-third of U.S. greenhouse-gas emissions in 2001.PHOTO/WADE SPEES

14 • COASTAL HERITAGE

15th Annual BeachSweep/River SweepSouth CarolinaSept. 20, 2003

Each year thousands of peopleparticipate in Beach Sweep/RiverSweep, South Carolina’s largest one-daylitter cleanup of beaches and waterways.The S.C. Sea Grant Consortium andS.C. Department of Natural Resourcesorganize the event, and anyone canparticipate—individuals, families,schools, civic clubs, or businesses.

Last year volunteers collected over59 tons of debris, but there is still moreto be done. To find out how you canhelp, call Susan Ferris, coastal coordina-tor, at (843) 727-2078 or BobbieAdams, inland coordinator, at (803)734-9108. For more information, visithttp://scseagrant.org/education/educa-tion bsrs.htm

Coastal Heritage is printedon recycled paper.

Web site: http://www.scseagrant.org

287 Meeting StreetCharleston, S.C. 29401

NON-PROFIT ORGU.S. Postage PaidCharleston, SCPERMIT #248

SUBSCRIPTIONS ARE FREE UPON REQUEST BY CONTACTING: ANNETTE.DUNMEYER@SCSEAGRANT.ORG

Science Serving South Carolina’s Coast

_

American FisheriesSociety 133rd

Annual MeetingQuebec City, QuebecAug. 10-14, 2003

“Worldwide decline of fishpopulations” is the theme for the2003 meeting, which will includesymposia, a trade show, studentactivities, poster sessions, andguided tours. The meeting will runfor four full days, with up to 20concurrent technical sessions.For more information, contactStephanie Lachance(418) 521-3955 orstephanie.lachance@fapaq.gouv.qc.ca

Oyster SummitMeetingAnnapolis, MarylandSept. 8-9, 2003

A conference, “Oyster Re-search and Restoration in U.S.Coastal Waters: Strategies for theFuture,” is scheduled for Sept. 8-9.Speakers at this meeting willsummarize the status of oysterfisheries in the United States, sharerecent developments in oyster-disease research, and synthesizedevelopments for management andrestoration of oyster populations.For more information, see http://www.mdsg.umd.edu/oysters/meeting