Institutions studying climate change

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Alaska Climate Research Center

Alliance to Save Energy

American Council for an Energy-Efficient

Economy American Electric Power American Gas Association American Geophysical Union American Meteorological Society Antarctic Meteorology Research Center Applied Energy Services, Inc.

Atmosphere, Climate and Environment Information

Programme (UK) Atmospheric Research and Information Centre BP

Canadian Association for Renewable Energies Cantor Fitzgerald EBS Center for Clean Air Policy Center for Energy Efficiency

Center for International Climate and Environmental Research

Center for International Environmental Law

Center for Ocean-Atmospheric Prediction Studies

Center for Science and Environment (India)

Climate Action Network

Climate Change Knowledge Network

Climate Impacts LINK Project

Climatic Research Unit

Colorado Climate Center

Cooperative Institute for Arctic Research

Cornell University

David Suzuki Foundation

Department of Energy, U.S.

Desert Research Institute

Edison Electric Institute

Environmental and Societal Impacts Group

Environmental Defense

Environmental Development Action in the

Third World Environmental Financial Products, LLC Environmental Protection Agency (EPA) European Commission FEEM (Italy) Florida State University

Foundation for International Environmental Law and

Development Friends of the Earth

Geophysical Fluid Dynamics Laboratory Global Atmospheric Research Program (GCRP) Global Environment Facility (GEF) Global Industrial and Social Progress Research

Institute (GISPRI) Greenpeace International Harvard University Heinz Center

Idaho State Climate Services Indiana University

Institute of Energy Economics (Argentina) Intergovernmental Panel on Climate Change (IPCC) International Council of Scientific Unions (ICSU) International Energy Agency (IEA) International Institute for Sustainable Development (IISD)

International Research Institute for

Climate Prediction International Solar Energy Society (ISES) International Union of Geodesy and

Geophysics (IUGG) Joint Institute for the Study of the Atmosphere and Ocean (JISAO) Kyoto Mechanisms LDEO Climate Modeling Group Marshal Institute

Midwestern Regional Climate Center National Academy of Sciences, U.S. National Association of Energy Service Companies (NAESCO)

National Center for Atmospheric Research (NCAR) Natsource

Natural Resources Defense Council (NRDC) New Mexico Climate Center OECD Annex I Expert Group on the UNFCCC OECD Climate Change Documents Ohio State University Oregon Climate Service Oregon State University Organisation for Economic Co-operation and Development (OECD)

Penn State University

Pew Center on Global Climate Change

Renewable Energy Policy Project (REPP)

Resources for the Future (RFF)

Royal Dutch/Shell Group

Royal Meteorological Society

Scripps Institute of Oceanography

Solar Energy Industries Association (SEIA)

Stockholm Environment Institute (SEI)

Tata Energy Research Institute (TERI)

Trexler and Associates, Inc.

UN Conference on Trade and Development/Earth

Council Institute: Carbon Market Program United Nations Development Programme (UNDP) United Nations Environment Programme (UNEP) University Corporation for Atmospheric Research University Corporation for Atmospheric Research

Joint Office for Science Support University of Arizona University of Birmingham, Meteorology and Climatology Department University of California University of Colorado

University of Delaware, Center for Climatic Research University of Florida

University of Hawaii, School of Ocean and Earth

Science and Technology University of Illinois, Department of

Atmospheric Sciences University of Kentucky, Agricultural Weather Center University of Leeds, Institute for

Atmospheric Science University of Maine, Institute for Quaternary Studies

University of Maryland, Department of Meteorology University of Miami University of Michigan University of New Hampshire University of Oklahoma, Weather Radar University of Reading, Department of Meteorology University of Utah, Department of Meteorology University of Washington, Atmospheric

Science Department Utah Climate Center Weather World 2010 Project Western Regional Climate Center Woods Hole Oceanographic Institute World Bank

World Business Council for Sustainable

Development World Meteorological Organization

World Resources Institute Worldwatch Institute World Wildlife Fund


Agulhas Current

Antarctic Circumpolar Current

Arctic Ocean

Atlantic Ocean

Benguela Current


Ekman Layer

Equatorial Undercurrent

Gulf Stream

Indian Ocean

Kuroshio Current

Meridional Overturning Circulation Mixed Layer

Modeling of Ocean Circulation Pacific Ocean Peruvian Current Salinity

Seawater, Composition of Somali Current Southern Ocean Thermocline

Thermohaline Circulation Upwelling, Coastal Upwelling, Equatorial Western Boundary Currents Wind-Driven Circulation


Cenozoic Era

Cretaceous Era

Earth's Climate History

Greenland Cores

Holocene Era

Jurassic Era

Mesozoic Era

Milankovitch Cycles

Orbital Parameters, Eccentricity

Orbital Parameters, Obliquity

Orbital Parameters, Precession

Paleozoic Era

Pleistocene Era

Pliocene Era

Precambrian Era

Quaternary Era

Tertiary Climate

Triassic Period

Vostok Core Younger Dryas


Arakawa, Akio Arrhenius, Svante August Bolin, Bert Broecker, Wallace Bryan, Kirk Bryson, Reid Budyko, Mikhail Chamberlin, Thomas C. Charney, Jule Gregory Croll, James Fourier, Joseph Gore, Albert, Jr. Hadley, George Hansen, James Keeling, Charles David Lindzen, Richard Lorenz, Edward Manabe, Syukuro Milankovitch, Milutin Munk, Walter Phillips, Norman Revelle, Roger Richardson, Lewis Fry Rossby, Carl-Gustav Schneider, Stephen H. Singer, S. Fred Smagorinsky, Joseph Stommel, Henry Sverdrup, Harald Ulrik Tyndall, John Von Neumann, John Walker, Gilbert Washington, Warren


CLIMAP Project

Framework Convention on Climate Change

International Geophysical Year (IGY)

International Geosphere-Biosphere Program (IGBP)

Kyoto Conference

Kyoto Protocol

Montreal Protocol

Toronto Conference

Vienna Convention

Villach Conference

World Climate Research Program

World Weather Watch

Encyclopedia of Global Warming and Climate Change

An Introduction

S. George Philander Princeton University in its 2007 report, the Intergovernmental Panel on Climate Change (IPCC), a large, international panel of scientists, all experts on the Earth's climate, concluded that human activities, specifically those that cause an increase in the atmospheric concentration of carbon dioxide, have started affecting the Earth's climate. The panel further predicted that far more significant climate changes are imminent. This report, and Al Gore's documentary An Inconvenient Truth are persuading a rapidly increasing number of people that human activities can lead to possibly disastrous global climate changes.

Those nonscientists are passionate about being wise and responsible stewards of the Earth, but at present they are handicapped because they take the words of the scientists on faith, and accept the reality of the threat of global warming without grasping the scientific reasons. This is most unfortunate, because our response to the threat of global warming is far more likely to be effective if it were motivated, not merely by the alarms scientists sound, but also by knowledge of how this very complex planet maintains the conditions that suit us so well. We need an awareness of how extremely fortunate we are to be the Earth's inhabitants at this moment in its long and eventful history, and an understanding of how our current activities are putting us at risk. The purpose of this encyclopedia is to help the reader learn about the intricate processes that make ours the only planet known to be habitable. This encyclopedia covers, in addition to the science of global warming, its social and political aspects that are of central importance to the ethical dilemmas that global warming poses: (1) How do we find a balance between regulations and freedom? (2) How do we find a balance between our responsibilities to future generations, and our obligations to the poor suffering today?

The first dilemma, which generates strong emotions, has caused an unfortunate polarization of a complex, multifaceted issue. The extremists who find regulations abhorrent assert that there is no evidence of global warming. (They are sometimes referred to as deniers or skeptics.) Their opponents, the believers, claim that global warming is underway, and is already causing environmental disasters. For believers, the second dilemma assumes global warming is already contributing to the suffering of the poor and therefore is an urgent priority for everyone. They refuse to accept that, for the many people who are so poor that they have nothing to lose, global warming is not an urgent issue. Dilemmas 1 and 2 call for compromises and hence for an objective assessment of the scientific results. The IPCC reports, which provide such an assessment, are explicit about uncertainties in the available results and hence favor neither the deniers nor the believers. The magnitudes of the uncertainties vary, depending on the time and region under consideration, and depending on whether we focus on temperature, the height of the ocean surface, rainfall or some other parameter.

The following is a very brief synopsis—a bird's eye view—of the discussion of these topics in the numerous entries of this encyclopedia. This information hopefully

Earth's temperatures fluctuate in a relatively narrow range; the Earth, unlike its neighbors Venus and Mars, is neither too warm nor too cold.

TiNY FRoM AFAR: in our solar system, Earth, third planet from the sun at left, is dwarfed by giants Jupiter and Saturn. The order of the planets starts with mercury, which is closest to the Sun, then Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and controversial Pluto.

TiNY FRoM AFAR: in our solar system, Earth, third planet from the sun at left, is dwarfed by giants Jupiter and Saturn. The order of the planets starts with mercury, which is closest to the Sun, then Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and controversial Pluto.

provides a basis for the development of an effective response to the threat of global warming.

Let us assume that we are aliens from another galaxy, in search of a habitable planet. On entering this particular solar system, our attention is at first drawn to the large, spectacular planets Jupiter and Saturn which are adorned with splendid rings and many moons. Earth, tiny by comparison, is a faint, blue dot from afar. Closer inspection shows that two of the Earth's main features are chaotically swirling white clouds, and vast oceans that cover nearly 70 percent of the surface. Both are vitally important to the Earth's most impressive feature of all: a great diversity of life forms that require water in liquid form. The abundance of liquid water means that, on the Earth, temperatures fluctuate in a relatively narrow range; the Earth, unlike its neighbors Venus and Mars, is neither too warm nor too cold.

The Earth's main source of energy is the sun, but this planet would be far too cold for most of its inhabitants were it not for its atmosphere, the thin veil of transparent gases that covers the globe. (If the Earth were an apple, its atmosphere would have the thickness of the peel.) This veil, by means of an intricate interplay between photons of light and molecules of air, serves as a shield that provides protection from dangerous ultraviolet rays in sunlight. The atmosphere serves as a parasol that reflects sunlight, thus keeping the planet cool; and as a blanket that traps heat from the Earth's surface, thus keeping us warm. The blanket is the greenhouse effect, which depends not on the two gases nitrogen and oxygen that are most abundant, but on trace gases that account for only a tiny part of the atmosphere, .035 percent in the case of carbon dioxide.

The most important greenhouse gas is water vapor, which is capable of engaging in escalating tit-for-tats (or positive feedbacks in engineering terms.) If atmospheric

SATELLITE VIEW: a photograph from space of a setting sun shows how thin the atmosphere is. If the Earth were an apple, its atmosphere would have the thickness of the peel.

temperatures were to increase by a modest amount, then evaporation from the oceans will increase, thus increasing the concentration of water vapor in the atmosphere. The result is an enhanced greenhouse effect that increases temperatures further, causing more evaporation, even higher temperatures, and so on. The consequence could be a runaway greenhouse effect—this is thought to be the reason why Venus has no water today. The Earth was spared this fate because it is further from the sun than Venus, and is sufficiently cool for the air to become saturated with water vapor, in which case clouds form. Clouds present the following question: Is their net effect cooling, because of the sunlight they reflect, or warming because of their greenhouse effect? The answer depends on the type of cloud. Occasional glances at the sky reveal that there are many, many types. Uncertainties about future global warming stem mainly from uncertainties concerning the types of clouds that are likely in a warmer world. Simulating these fantastical, ephemeral objects is the biggest challenge for scientists trying to reproduce climate in computer models.

If the atmosphere were static, we would be confined to a band of mid-latitudes, because the tropics would be too hot, the polar regions too cold. Fortunately, the atmosphere has winds that redistribute heat and also moisture, cooling off the lower

The westerly jet streams are so intense that some bands of latitude are known as the Roaring Forties and the Screaming Fifties.

latitudes, while warming up higher latitudes. The circulation that effects this redistribution includes surface winds that are easterly (westward) in the tropics, where they converge onto the regions of maximum surface temperature at the equator. There the air rises into tall cumulus towers that provide plentiful rain. Aloft, the air flows poleward, cools, and sinks over the subtropical deserts. Some of the air continues further poleward to join the westerly jet streams that are so intense that some bands of latitude are known as the Roaring Forties and the Screaming Fifties. This atmospheric circulation, despite its chaotic aspects that we refer to as weather, creates distinctive climatic zones—jungles and deserts, prairies and savannahs—that permit enormous biodiversity.

In the tropics, the atmospheric circulation, and hence the pattern of climatic zones, are strongly dependent on patterns of sea surface temperature that influence how much moisture the winds take (evaporate) from the ocean, and then deposit in rain-bearing clouds. The most surprising feature in the sea surface temperature patterns is the presence of very cold surface waters right at the equator in the eastern Pacific Ocean. (When he visited the Galapagos Islands, Charles Darwin commented on the curiously cold water at the equator where sunlight is most intense.) To explain this we need to explore the oceans, the thin film of water that covers much of the globe.

The average depth of the ocean, 3.1 miles or 5 kilometers, is negligible in comparison with the radius of the Earth, which is more than 3,700 miles or 6,000 kilometers. Both the atmosphere and ocean are very thin films of fluid, one air, the other water. Measurements made on expeditions from Antarctica to Alaska show that the ocean

01 23456789 10 11 12 Precipitation (mm/day)

PRECIPITATION MAP: There is a strong relationship between amount of precipitation and ocean temperature. Charles Darwin remarked on the surprisingly cold waters off the Galapagos Islands.

EARTH LIGHTS FRoM SPAcE: This map by NASA shows a composite image of lights on Earth, but both the landforms and lights appear brighter than would be visible to an unaided observer in space. researchers were able to produce this map of lights showing urban surface activity.

BRIGHT LIGHTS, BIG ciTY: What becomes remarkably clear in this image is the energy usage in the United States, western Europe, and Japan, as compared to Africa and the rest of the world. The major national and regional contributors to greenhouse gas emissions are evident.

is composed of a very shallow layer of warm water that floats on a much colder, deep layer. So shallow is the warm layer that, at the equator near the dateline where the surface waters are warmest, the average temperature of a vertical column of water is barely above freezing. An important consequence is that the winds blowing in the right direction can easily expose cold water to the surface by driving oceanic currents in the right direction. The westward trade winds do this along the equator. They drive the warm surface water westward, causing cold water to appear near the Galapagos Islands. Winds parallel to the western coasts of Africa and the Americas, north and south, similarly drive currents that bring cold water to the surface.

Some of the oceanic currents are very slow and deep, others are swift and shallow and include the Gulf Stream and Kuroshio—narrow, rivers of warm water that flow poleward. These currents redistribute heat and chemicals, thus determining patterns of sea surface temperature and oceanic climatic zones that are evident in satellite photographs of the distribution of chlorophyll at the surface of the Earth. Chlorophyll is produced by phytoplankton, literally plants that wander. Those plants, and other life forms that depend on them, are most abundant near the ocean surface, because they need light that penetrates only tens of feet or meters below the ocean surface. When that living matter dies, it sinks and decomposes so that the cold, deep ocean is rich in nutrients.

It follows that ideal conditions for biological productivity—an abundance of light and nutrients—exists where the deep water rises to the surface. These are known as the oceanic upwelling zones, where surface waters are cold, such as off the western coasts of the Americas and Africa. The absence of a layer of warm surface waters around Antarctica makes the Southern Ocean another highly productive zone. Note that the subtropical ocean basins are in effect oceanic deserts with very few plants, because there is practically no exchange between the warm surface waters and the cold water at depth.

The plants on land and at sea, by means of photosynthesis, capture carbon dioxide from the atmosphere during their growing season, and return it when they die and

JULY AND JANUARY: True color composite satellite maps of the Earth's surface in July (above) and January 2004 (at right) from NASA illustrate the significance of seasonal snowfall.

decay. This continual flow of carbon between the ocean, atmosphere, and biosphere (the assemblage of all life on Earth) causes variations in the atmospheric concentration of carbon dioxide. Many people think of the composition of the atmosphere as fixed, in the way that water in a glass is composed of two parts hydrogen and one part oxygen. In reality the atmospheric composition changes continually because each constituent participates in a biogeochemical cycle. (The best known is the hy-drological cycle, which is associated with continual changes in the atmospheric concentration of water vapor.) At present, we are interfering with the carbon cycle by burning fossil fuels, and thus emitting carbon into the atmosphere. The oceans and the plants absorb a large fraction, but much remains in the atmosphere so that the concentration there is rising rapidly.

The ocean, atmosphere, and biosphere form a complex interacting system capable of generating fluctuations on its own. This is known as natural variability, in contrast to variability forced by daily and seasonal changes in sunlight, or by human-induced changes in the composition of the atmosphere. Daily changes in the weather, the best-known examples of natural variability, are as natural as the swings of a pendulum and would be present even if there were no variations in sunlight. Another natural fluctuation, with a much longer timescale of years rather than days, is the oscillation between El Niño and La Niña in the Pacific Ocean. From a strictly oceanic perspective, these phenomena are associated with changes in sea surface temperatures, in the currents, and so on, that are attributable to changes in the winds. Along the equator, those winds are intense during La Niña, weak during El Niño. Why do the winds change? From a meteorological perspective, the large

ALBEDo EFFEcT: Snow-covered regions effectively cool the Earth by reflecting sunlight back into space, and hence changes in the range of snow cover can serve to amplify climate changes.

A thousand years ago, the northern Atlantic was so warm that Greenland had a large enough population for the pope to send a bishop.

temperature contrast between the western and eastern equatorial Pacific during La Niña drives intense winds that weaken when the contrast weakens. This circular phenomenon—atmospheric changes are both the cause and consequence of oceanic changes—implies that El Niño and La Niña are consequences of interactions between the ocean and atmosphere.

We know a great deal about daily changes in weather because we have ample opportunities to study those changes. Over the past few decades, we learned a fair amount about El Niño, because that phenomenon occurred several times during that period. The past centuries and millennia were also characterized by naturally occurring fluctuations, but information about those climate fluctuations is scant, because of the lack of instrumental records. A thousand years ago, the northern Atlantic was so warm that Greenland had a large population, sufficiently large for the Pope to send a bishop.

That warm period was followed by the frigid Little Ice Age. Those changes were presumably aspects of natural variability, but as yet they are unexplained. Because we know very little about natural variability, it is not possible to determine whether a few unusually warm years, or a few intense hurricanes such as Katrina, or the unusually strong El Niño of 1997, indicate the onset of global warming. Scientists had to search carefully for distinctive patterns, for the "footprints" of global warming, before they could conclude in the 2007 IPCC report that humans activities are affecting the global climate.




NATURAL FLUcTUATioN: With a timescale of years rather than days, the oscillation between El Niño and La Mña in the Pacific ocean governs weather patterns and storm activity.


NATURAL FLUcTUATioN: With a timescale of years rather than days, the oscillation between El Niño and La Mña in the Pacific ocean governs weather patterns and storm activity.

Salinity (PSS)

ocEAN cURRENTS: The warm surface currents (red) intertwine with the deep cold currents (blue), creating climate patterns across the Earth. (robert Simons/NASA)

The composition of the atmosphere, which strongly influences climate, depends on biogeochemical cycles involving not only the ocean, atmosphere and biosphere, but also the solid Earth. Terra firma is anything but firm; its surface is composed of several slowly moving, nearly rigid plates, on some of which the continents float. This is the surface manifestation of motion deep in the interior of the Earth, where temperatures are very high because of the decay of radioactive material. Earthquakes are common along the plate boundaries, which feature tall mountains where the plates collide, or deep trenches where one plate dives (subducts) beneath another. In regions of subduction, volcanoes are common; that is why the Pacific rim is known as a "ring of fire." When they erupt, volcanoes emit carbon dioxide into the atmosphere. That gas interacts with water vapor to form an acid that erodes rocks, causing the removal of carbon dioxide from the atmosphere. Hence, the building of mountains—the creation of extensive rock surfaces—promotes the removal of carbon dioxide from

Some 65 million years ago, the Earth was so warm that there was no ice on the planet. Palm trees and crocodiles flourished in polar regions.

20 30 40 50 60 70 80 F

Mean Annual Air Temperature

Mean Annual Air Temperature

TEMPERATURE MAP: The areas in dark red with the highest temperatures correlate to the Precipitation Map—regions with the highest precipitation are also the warmest.

the atmosphere. Continental drift therefore affects the atmospheric composition by bringing into play processes that increase, and others that decrease, the concentration of carbon dioxide. Volcanic eruptions contribute to the increase, the building mountains to the decrease. Continental drift affects climate in a more direct manner by changing the distribution of continents. At one time all the continents were together and formed a supercontinent, Pangea, with a northern part known as Lau-rasia, and a southern Gondwanaland that included the Antarctic continent. With the breakup that started around 250 million years ago, Africa and South America separated to form the Atlantic Ocean. India traveled northward until it collided with Asia, and started creating the Himalayas.

For those interested in global warming, what happened after the demise of the dinosaurs some 65 million years ago is of special interest. At that time, the Earth was far warmer than it is today, so warm that there was no ice on the planet. Palm trees and crocodiles flourished in polar regions, in part because the atmospheric concentration of carbon dioxide was much higher than it is today. Subsequently, the continued drifting of the continents, accompanied by decreases in the atmospheric concentration of carbon dioxide, contributed to the global cooling. (This period is known as the Cenozoic, the age of new animals, specifically mammals.) What caused the Ice Ages? Why did they start 3 million years ago? The answers involve slight changes in sunlight. Sunlight varies daily and seasonally because the Earth rotates on its tilted axis once a day, while orbiting the sun once a year. Additional variations over

Introduction xxix much longer periods of thousands of years are associated with slight oscillations of the tilt of the axis, which also precesses, while the orbit changes gradually, from a circle into an ellipse, and back to a circle. The moon and several planets cause these Milanko-vitch cycles, which have been present throughout the Earth's history. The climate fluctuations induced by these sunlight cycles were modest up to 3 million years ago, but then started amplifying. That amplification required positive feedbacks that translated the slight variations in sunlight into Ice Ages. The feedbacks were brought into play by the drifting of the continents. A complex and poorly understood interplay between the slow, erratic drifting of continents, and the regular variations in sunlight, caused the Ice Ages to be absent during some periods, and prominent during others, such as the present.

The global cooling associated with the drifting of the continents that started 60 million years ago inevitably led to the appearance of glaciers, first on Antarctica, then on northern continents around 3 million years ago. Glaciers, because they are white, reflect sunlight. This deprives the Earth of heat, lowers temperatures, and

Glaciers, because they are white, reflect sunlight. This reflection deprives the Earth of heat, lowers temperatures, and promotes the growth of glaciers.

HURRICANE PATHS: A plot of the intensity and paths of hurricanes and typhoons. How global warming will affect the development and strength of storms is a subject of debate and study.
PoTENTIAL FLooDING: This is a topographic map designed to emphasize regions near sea level that could potentially be vulnerable to sea level rise, though over centuries rather than decades.

promotes the growth of glaciers. Hence, the appearance of continental glaciers was one of the feedbacks that amplified the response to Milankovitch variations in sunlight. Trapped in those glaciers are bubbles of air that tell us about past changes in the atmospheric composition, past variations in the atmospheric composition of carbon dioxide. As yet it is not known why the concentration varied, or to what degree the variations contributed to the temperature fluctuations.

Solving the puzzle of the Ice Ages will be a major contribution to our ability to anticipate future climate changes, because the solution will tell us a great deal about the sensitivity of the Earth's climate to changes in the atmospheric concentration of carbon dioxide. In the meanwhile, familiarity with the data can give us a valuable perspective on global warming by giving us a geological context for our activities over the past century. From a geological perspective, the present is a special moment

in the history 0 our planet for at leasttwo reasons. The first is that the Earth is currently in an era of high sensitivity to small disturbances. Starting approximately 3 million years ago, the Earth's response to slight variations in sunlight, the Milanko-vitch cycles, have included enormous climate fluctuations associated with recurrent Ice Ages. Only some of the feedbacks that are involved have been identified. The second reason why the present is special is that we are currently enjoying the temperates of one of the brief interglacial periods that separate prolonged Ice Ages.

The previous interglacial was more than 100,000 years ago but, at that time, we humans were few in numbers, and had very limited capabilities. We were ready when the current interglacial started, some 10,000 years ago, and proceeded to advance with astonishing rapidity, inventing agricultures, domesticating certain animals, developing cultures, and building cities. We developed so rapidly that we are now

12-B 4

Climate Change Recorded in Ocean Sediments

Polar Ocean

Temperature Shift (°C)

Formation of the Antarctic Ice Sheet



280 230180-

Ice Age Cycles Recorded in Ice

380 360 340320300 280 260

Temperature Reconstructions Carbon Dioxide f •••>•'

Ice Age Cycles Recorded in Ice

280 230180-

0 Thousands of Years Ago 0.6

4 Estimated

0 Temperature Shift in 4 Central Antarctica (°C) 8

Millions of Years Ago

Temperature Reconstructions Carbon Dioxide f •••>•'

Instrumental Measurements

Temperature Shift in Central Antarctica (°C)

Carbon Dioxide in Earth's Atmosphere

0 Thousands of Years Ago 0.6

-0.3 -0 0.3 0.6

Global Average Temperature Shift (°C)





2000 1850 1900 1950 2000 Calendar Year (AD)

HISToRY of cLIMATE cHANGE: A compound graphic depicts Earth's climate change across the millennia and centuries. Top: Global cooling over the past 60 million years. middle: recurrent ice ages over the past 600,000 years. Bottom: rise in temperature and carbon dioxide over the past four centuries. The information in the top panel comes from cores drilled into the ocean floor, where sediments contain remains of primitive organisms that live near the ocean surface. the information in the middle panel comes from antarctica, where the accumulated snowfall of hundreds of millennia created deep glaciers.

geologic agents, capable of interfering with the processes that make this a habitable planet. For more than a century, we have caused the atmospheric concentration of carbon dioxide to grow exponentially. This, surely, is a time for circumspection and caution.

Maps and Plots Prepared by Robert A. Rohde University of California, Berkeley

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Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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