Encyclopedia of Global Warming & Climate Change

Encyclopedia of Global Warming & Climate Change


Edited by: S. George Philander


The First Edition of the Encyclopedia of Global Warming and Climate Change provided a multi-authored, academic yet non-technical resource for students and teachers to understand the importance of global warming, to appreciate the effects of human activity and greenhouse gases around the world, and to learn the history of climate change and the research enterprise examining it. This edition was well received, with notable reviews. Since its publication, the debate over the advent of global warming at least partially brought on by human enterprise has continued to ebb and flow, depending literally on the weather, politics, and media coverage of climate summits and debates. Advances in research also change the discourse as new data is collected and new scientific projects continue to explore and explain ...

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    • Atmospheric Sciences
    • Climate
    • Climate and Society
    • Climate Change, Effects
    • Climate Feedbacks
    • Climate Models
    • Countries: Africa
    • Countries: Americas
    • Countries: Asia
    • Countries: Europe
    • Countries: Pacific
    • Glaciology
    • Institutions Studying Climate Change
    • Oceanography
    • Paleoclimates
    • People
    • Policies and Conventions
    • U.S. Government and International Agencies
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      Reader's Guide

      About the Editor

      S. George Philander, Knox Taylor Professor of Geosciences at Princeton University and Research Director of ACCESS (African Centre for Climate and Earth System Science) in Cape Town, South Africa, has a Bachelor of Science degree from the University of Cape Town and a Ph.D. (Applied Mathematics) from Harvard University.

      He is a member of the National Academy of Sciences and a fellow of the American Academy of Arts and Sciences, the American Geophysical Union, and the American Meteorological Society. Philander's research interests include oceanic circulation, interactions between the ocean and atmosphere that result in phenomena such as El Niño and La Niña, paleoclimates (including the recurrent Ice Ages of the past 3 million years), and future global climate changes. His two books for laypersons, Is the Temperature Rising? The Uncertain Science of Global Warming and Our Affair With El Niño: How We Transformed an Enchanting Peruvian Current Into a Global Climate Hazard, reflect his keen interest in improving communications between scientists and laymen.

      The goal of the African Centre for Climate and Earth System Science, which Philander is currently directing, is to give Africa a voice on environmental issues such as global warming.

      List of Contributors

      Pradeep Adhikari, University of Oklahoma

      Linus Adler, Independent Scholar

      Ruth Adler, Case Western Reserve University

      Oluseyi Olanrewaju Ajayi, Covenant University

      Rais Akhtar, Jawaharlal Nehru University

      Ezgi Akpinar-Ferrand, University of Cincinnati

      Warren D. Allmon, Paleontological Research Institution

      Aileen Anderson, Independent Scholar

      Giorgio Andrian, University of Novi Sad

      Natalia Andronova, University of Michigan

      Robert M. Atkinson, Brandenburg University of Technology

      Andrea S. Auerbach, ERG Inc.

      Karl Auerbach, University of Rochester

      Maximilian Auffhammer, University of California, Berkeley

      Caitlin M. Augustin, University of Miami

      Andrew S. Backe, National Science Foundation

      Barbara Bader, Université Laval

      Bhavik R. Bakshi, Ohio State University

      Joaquim Ballabrera, UTM-CSIC

      Patricia Ballamingie, Carleton University

      Michael Baltek, University of Baltimore

      Kaushik Ranjan Bandyopadhyay, TERI University

      Michal Bardecki, Ryerson University

      John H. Barnhill, Independent Scholar

      Lisa Beal, University of Cape Town

      Martin Beniston, University of Geneva

      Nsikak Benson, Covenant University

      Donald J. Berg, South Dakota State University

      Asmeret Asefaw Berhe, University of California, Merced

      Andrea C. S. Berringer, Louisiana State University

      P. Dee Boersma, University of Washington

      Maria Borovnik, Massey University

      Sarah Boslaugh, Kennesaw State University

      Mary Brickle, University of Richmond

      Stefan Brönnimann, Institute for Atmospheric and Climate Science

      Jeremy Bryson, Northwest Missouri State University

      William C. G. Burns, Journal of International Wildlife Law & Policy

      John Byun, Harvard University

      Julien Chevallier, Université Paris-Dauphine

      Matthew K. Chew, Arizona State University

      Jongnam Choi, Western Illinois University

      Jun-Ki Choi, Ohio State University

      Zachary Christman, Middlebury College

      Abbey E. Chrystal, Ohio State University

      Jennifer E. Coffman, James Madison University

      Jill S. M. Coleman, Ball State University

      Timothy Collins, Western Illinois University

      Jeff Conant, Global Justice Ecology Project

      Sandra Connelly, Rochester Institute of Technology

      Justin Corfield, Geelong Grammar School

      Robin S. Corfield, Independent Scholar

      Ellen Jeanne Crivella, GL Garrad Hassan

      Richard A. Crooker, Kutztown University

      Chris J. Cuomo, University of Georgia

      Christopher Cumo, Independent Scholar

      Kasturi Das, Research and Information System for Developing Countries

      C. R. de Freitas, University of Auckland

      Vito De Lucia, University of Tromsø

      Leonardo Freire de Mello, University of Valedo Paraíba

      Wilhelmus P. M. de Ruijter, University of Cape Town

      Lester de Souza, Independent Scholar

      Claudio O. Delang, Chinese University of Hong Kong

      Jansenio Delgado, ECOWAS Regional Centre for Renewable Energy and Energy Efficiency

      Laurence Laurencio Delina, Independent Scholar

      Robin K. Dillow, Oakton Community College

      P. Grady Dixon, Mississippi State University

      Magali Dreyfus, United Nations University Institute of Advanced Studies

      Lawrence K. Duffy, University of Alaska, Fairbanks

      Philip B. Duffy, Lawrence Livermore National Laboratory

      James Edmunds, Thames Valley University

      Richard Milton Edwards, University of Wisconsin Colleges

      Charles Ehrhart, CARE International's Poverty Environment and Climate Change Network

      Hyacinth Elayo, ECOWAS Regional Centre for Renewable Energy and Energy Efficiency

      Christopher J. Ennis, University of Teesside

      Harriet Ennis, Bootham School

      Mary Finley-Brook, University of Richmond

      Marlon Flores, Ecologic Institute

      Gregory R. Foltz, University of Washington/JISAO

      Jordi Font, CMIMA/CSIC

      Al Gabric, Griffith University

      Karl-Heinz Gaudry, University of Freiburg

      Teamrat A. Ghezzehei, University of California, Merced

      Christian P. Giardina, Institute of Pacific Islands Forestry

      Shannon Gibson, University of Miami

      Kyle Brian Gracey, Global Footprint Network

      Steven A. Gray, Rutgers School of Environmental and Biological Sciences

      Wulf Greve, German Centre for Marine Biodiversity Research

      Velma I. Grover, York University

      Michael M. Gunter, Jr., Rollins College

      Gyorgyi Gurban, PPKE-JAK Law School

      Maria Gutierrez, International Institute for Sustainable Development

      Florian Habermacher, University of St. Gallen

      Benjamin Hale, University of Colorado, Boulder

      Randolph Haluza-DeLay, King's University College

      Edward Hanna, University of Sheffield

      Phillip Matthew Hannam, UNEP-Tongji Institute of Environment

      Jonathan Harrington, Troy University

      Ingrid Hartmann, University of Hohenheim

      Jason A. Helfer, Knox College

      Cary Yungmee Hendrickson, University of Rome

      Fernando Herrera, University of California, San Diego

      Stephen Keith Holland, James Madison University

      Arthur Matthew Holst, Widener University

      Pandora Hope, Centre for Australian Weather and Climate Research

      David V. Howe, Rutgers School of Environmental and Biological Sciences

      Iva Hristova, Université Paris Dauphine

      Douglas William Hume, Northern Kentucky University

      Andrew Hund, Independent Scholar

      Kent L. Hurst, University of Texas at Arlington

      Kayo Ide, University of Maryland

      Daniel Kweku Baah Inkoom, Kwame Nkrumah University of Science and Technology

      Shafi Noor Islam, Brandenburg University of Technology

      Lyn Jaggard, Independent Scholar

      Rebecca C. Jordan, Rutgers School of Environmental and Biological Sciences

      Courtney D. Jude, Knox College

      Peter Kimosop, Bowling Green State University

      Robert Karl Koslowsky, Independent Scholar

      Bill Kte'pi, Independent Scholar

      Yves Laberge, Université Laval

      Erick Lachapelle, Université de Montréal

      Kevin T. Law, Marshall University

      Donald H. Lenschow, National Center for Atmospheric Research

      Estella B. Leopold, University of Washington

      Elena Lioubimtseva, Grand Valley State University

      Loykie L. Lomine, University of Winchester

      Valerio Lucarini, University of Bologna

      Martin Lugmayr, ECOWAS Regional Centre for Renewable Energy and Energy Efficiency

      Johann R. E. Lutjeharms, University of Cape Town

      Scott Macmurdo, Columbia University

      Rafael D'Almeida Martins, State University of Campinas

      Saumalu Mataafa, Embry-Riddle Aeronautical University

      Emily McGlynn, U.S. Department of State

      Phil McManus, University of Sydney

      Carlos R. Mechoso, University of California, Los Angeles

      Michael Mehling, Ecologic Institute

      Ina Christin Meier, University of Göttingen

      Walter N Meier, National Snow and Ice Data Center

      Christopher D. Merrett, Western Illinois University

      Lyn Michaud, Independent Scholar

      Heather K. Michon, Independent Scholar

      B. J. Milmoe, George Mason University

      Stefano Moncada, University of Malta

      Marvin Joseph Fonacier Montefrio, State University of New York College of Environmental Science and Forestry

      Tara Moran, University of Calgary

      Peta Mudie, Natural Resources Canada

      Dustin R. Mulvaney, University of California, Berkeley

      Conor Murphy, National University of Ireland, Maynooth

      Raghu Murtugudd, University of Maryland

      Jamal A. Nelson, Knox College

      Katja Neves, Concordia University

      Anastasia Northland, University of Miami

      Ann Novogradec, York University

      Melissa Jane Nursey-Bray, University of Adelaide

      Astrid E. J. Ogilvie, University of Colorado

      John O'Sullivan, Gainesville State College

      Carl Palmer, University of Cape Town

      Sudhanshu Sekhar Panda, Gainesville State College

      Edward Christien Michael Parsons, George Mason University

      Joshua M. Pearce, Queen's University

      Anders Branth Pedersen, Aarhus University

      Jonathan Peyton, University of British Columbia

      S. George Philander, Princeton University

      Anthony D. Phillips, Ball State University

      Jarmila Pittermann, University of California, Santa Cruz

      Alexander Boris Polonsky, Marine Hydrophysical Institute, Sevastopol

      Francesca Pongiglione, University of Bologna

      Christopher J. Poulsen, University of Michigan

      Kirsty Pringle, University of Leeds

      Luca Prono, Independent Scholar

      Mark Purdon, University of Toronto

      Elizabeth Rholetter Purdy, Independent Scholar

      Gordon P. Rands, Western Illinois University

      Pamela J. Rands, Western Illinois University

      Dave S. Reay, University of Edinburgh

      Ginger A. Rebstock, University of Washington

      Alan B. Reed, University of New Mexico

      Nilton O. Renno, University of Michigan

      Wylene Rholetter, Independent Scholar

      Barbara Ann Ribbens, Western Illinois University

      Eric Ribbens, Western Illinois University

      Robert V. Rohli, Louisiana State University

      Naomi A. Rose, Humane Society International

      Robert M. Ross, Paleontological Research Institution

      Summer Rupper, Brigham Young University

      Bah F. M. Saho, ECOWAS Regional Centre for Renewable Energy and Energy Efficiency

      Johnathan P. Sanders, University of California, Riverside

      Jenniffer Marie Santos-Hernández, Oak Ridge National Laboratory

      Tyler Sayers, Western Illinois University

      Ethan D. Schoolman, University of Michigan

      Stephen T. Schroth, Knox College

      Sebastian Schulze, Brandenburg University of Technology

      Jacob O. Sewall, Virginia Polytechnic Institute and State University

      Paul Sheeran, University of Winchester

      Rahul J. Shrivastava, Florida International University

      Jules R. Siedenburg, University of East Anglia

      M. P. Simmonds, Whale and Dolphin Conservation Society

      Michael Joseph Simsik, U.S. Peace Corps

      Amber Sinclair, University of Georgia

      Kate E. Sinclair, University of Calgary

      James N. Smith, National Center for Atmospheric Research

      Mary M. Snow, Embry-Riddle Aeronautical University

      Richard K. Snow, Embry-Riddle Aeronautical University

      Jelena Srebric, Pennsylvania State University

      Krishna Ravi Srinivas, Research Information System for Developing Countries

      E. Natasha Stavros, University of Washington

      Cecily Natunewicz Steppe, U.S. Naval Academy

      David Stevenson, University of Edinburgh

      Geoff Stiles, Independent Scholar

      Julienne Stroeve, University of Colorado

      Bruno Takahashi, State University of New York

      John Manyitabot Takang, University of Cologne

      Hill Taylor, North Carolina State University

      Melvin E. Taylor, Jr., Knox College

      Teagan Tomlin, Brigham Young University

      Marcella Bush Trevino, Barry University

      Derek Turner, Connecticut College

      Bart Verheggen, Energy Research Centre of the Netherlands

      Elena Voskresenskaya, Marine Hydrophysical Insitute, Sevastopol

      John Walsh, Shinawatra University

      Karin Warren, Randolph College

      Andrew Jackson Waskey, Jr., Dalton State College

      Margreet Wewerinke, European University Institute

      Ken Whalen, University of Brunei Darussalam

      Mark Whitehead, Aberystwyth University

      Holly M. Widen, Ball State University

      Akan Bassey Williams, Covenant University

      Claudia Winograd, University of Illinois at Urbana-Champaign

      Erika K. Wise, University of North Carolina at Chapel Hill

      Diana Pei Wu, Antioch University, Los Angeles

      Weimin Xi, University of Wisconsin, Madison

      Komalirani Yenneti, University of Birmingham

      Xiaochen Zhang, Virginia Polytechnic Institute and State University

      Petra A. Zimmermann, Ball State University


      Global warming has become an extremely divisive issue. Recent polls indicate an increase in the percentage of laymen who are skeptical of the threat of global warming, even though the vast majority of scientists accept the reality of this threat. Scientists are aware of recent advances in the acquisition and analyses of climate data, and in the development of theories and models that explain and simulate various aspects of climate. Laymen, on the other hand, pay attention to the failure of governments, for example, at a well-publicized international conference in Copenhagen, Denmark, in December 2009, to reach any agreement on how to respond to global warming. That conference was in the wake of “Climate-Gate,” the controversy started by hackers who released thousands of e-mails, exchanged between climate scientists around the globe, and stored on a computer of the Climate Research Unit at the University of East Anglia (UK). Allegations that the e-mails provide evidence that the scientists manipulate climate data to serve their political purposes have been found baseless, but the unfortunate polarization of opinions concerning a matter of vital importance, the future habitability of planet Earth, persists. The goal of this encyclopedia is to bridge the gulf between laymen and scientists.

      The future of our planet, the only one known to be habitable, is too important to be left to experts. Everyone should participate in discussions of global warming and to that end should have a rudimentary understanding of how the Earth functions, how it maintains the climatic conditions that suit us so well. Those conditions have allowed us to make remarkable technological advances over the past century. We have become so powerful that we are now geologic agents, capable of interfering with the processes that make this a habitable planet.

      We have therefore become the stewards of the only planet known to be blessed with a glorious diversity of plants and animals. This encyclopedia provides information that can help us be wise and responsible stewards. To do so, it keeps in mind that its readers have diverse backgrounds: The activities of conservation biologists are of interest to economists; political scientists wish to know whether certain environmental problems are best solved by regulations or market forces; and businesspeople, government officials, and politicians request briefs on the latest scientific results.

      To be useful to such a diversity of people, the nearly 800 entries in this three-volume encyclopedia cover a vast range of topics affecting global warming and climate change. In this, the second edition of the encyclopedia, some 50 percent of the contents have been updated and revised and 40 entirely new articles have been added. Moreover, the online edition features some 50 video clips that complement the articles. The entries amount to more than a catalog of terms; they are all part of one story about global warming and how it is likely to affect our world.

      Scientific objectivity has been the watchword for the editors of this encyclopedia, yet different perspectives that various authors have on some of these issues are part of a conversation that citizens or students concerned about the environment ignore at their own risk. Even the title of the work, Encyclopedia of Global Warming and Climate Change, was carefully considered to include paleoclimatology in the discussion of weather, climate, and the current debate about global warming.

      The authors of the entries include geographers, political scientists, chemists, anthropologists, medical practitioners, development experts, and sociologists. They are experts in their fields of specialty; many are researchers with extensive field-work experience; most of the entries on emerging techniques and technologies were written by innovators. As the volumes intend, it has become increasingly essential to bring the multiplying global warming issues, concepts, theories, examples, problems, and policies together in one place, with the goal of clearly explaining an emerging way of thinking about people and their planet.

      Among the selection of articles, specific country entries are included, rather than climatic or environmental regions, to give the reader the opportunity to get information on the status of global warming—its causes and effects—by country, from Afghanistan to Zimbabwe. Also included are articles within specific categories, including: atmospheric sciences; climate; climate and society; climate change effects; climate feedbacks; climate models; institutions studying climate change; oceanography; paleoclimates; policies and conventions; and people studying climate change. Altogether, we hope the encyclopedia provides some groundwork for further discussion and spur possible action to curb global warming.

      S. GeorgePhilanderGeneral Editor


      4.5 billion years ago

      The Earth, newly formed, had the hottest climate in the planet's long history. Temperatures were hot enough to liquefy rock. Radioactive elements in the Earth's core generated heat and pressure as they decayed, pushing molten rock toward the surface. Volcanoes also brought molten rock to the surface, liberating heat and spewed carbon dioxide, causing the greenhouse effect.

      3.8 billion years ago

      As the mass of radioactive elements in the Earth's core diminished, the climate cooled and the first rocks formed. The cooling of the atmosphere liquefied water vapor, which fell to the Earth as rain.

      3.5 to 3 billion years ago

      The origin of life enhanced the cooling of the climate, for among the first life were single-celled photosynthetic algae. Like plants, these algae consumed carbon dioxide and exuded oxygen. The reduction of carbon dioxide in the atmosphere weakened the greenhouse effect. With the reduction in carbon dioxide, temperatures dropped below freezing, causing the planet's first ice age 3 billion years ago.

      2.9 billion years ago

      The retreat of the glaciers inaugurated a long period of warm climate. The sun, burning steadily brighter, bathed the Earth in its heat. Warm inland seas covered the planet, moderating the climate. Ocean currents circled the globe, spreading warm water from the equator to the poles.

      800 to 550 million years ago

      Glaciers covered the oceans as well as the land, killing photosynthetic algae that lived in the ocean. With algae in small numbers they were able to remove only a fraction of carbon dioxide from the atmosphere. With no check on its accumulation, carbon dioxide increased in the the Earth's atmosphere, causing the greenhouse effect. The greenhouse effect ended the Late Proterozoic Ice Age, roughly 550 million years ago, inaugurating a new, warmer period for the planet.

      350 to 280 million years ago

      The lush plant growth of the Carboniferous Era confirmed that the climate was warm and that carbon dioxide, essential for plant growth, was abundant.

      230 million years ago

      The continents gathered into a single landmass called Pangea. Because it was near the equator, Pangea's climate was tropical.

      135 to 65 million years ago

      Temperatures soared 20 degrees F (11 degrees C) warmer than today's temperatures during the Cretaceous Era. Forests covered Antarctica. Ocean currents again carried warm water to the poles.

      65 million years ago

      An enormous meteor impacted the Earth, ejecting a gigantic cloud of debris and dust. It ignited widespread fires, which pumped ash into the atmosphere. The debris, dust, and ash blocked out much of the sun's light, chilling the climate. So severe was the reversal in climate that the dinosaurs and a large number of marine species, unable to cope with the new conditions, perished.

      55 to 35 million years ago

      Temperatures declined 20 degrees F (11 degrees C). Glaciers formed on Antarctica.

      130,000 years ago

      The climate was again warmer than it is today. The water from melting glaciers flowed to the oceans, raising the sea level 60 ft. (18 m) higher than it is today.

      100,000 years ago

      The climate cooled yet again and glaciers once more spread across the continents, plunging the Earth into its most recent ice age.

      16,000 to 13,000 years ago

      The glaciers were in retreat, temperatures rose nearly 15 degrees F (9 degrees C).

      12,900 and 11,500 years ago

      Temperatures during the Younger Dry as fell 50 degrees F (28 degrees C) in only a decade.

      7,000 years ago

      Temperatures peaked at 2–3 degrees F (1–1.5 degrees C) above current temperatures. The climate remained warm and wet for another 3,000 years.

      900 to 1300 c.e.

      The Medieval Warm Period rewarded peasants with bountiful crops. With warmer temperatures and food in surplus, the Earth's human population increased.

      1400 to 1840

      The Little Ice Age covered the globe with record cold, large glaciers, and snow. This massive climate change triggered disease, famine, and death. Today, many scientists around the world believe that global warming caused by the greenhouse effect will be the fastest warming of the Earth since the termination of the Little Ice Age.


      French mathematician and physicist Jean Baptiste Joseph Fourier established that a buildup of carbon dioxide in the Earth's atmosphere warms the climate.


      Irish scientist John Tyndall discovered that some gases block infrared radiation. He suggested that changes in the concentration of the gases could bring about climate change.


      Tyndall announced that water vapor is a greenhouse gas.


      British scientist James Croll established that ice and snow reflect sunlight into space and cool the Earth.


      Swedish scientist and Nobel laureate Svente Arrhenius coined the phrase greenhouse effect and predicted that the Earth's climate is slowly warming. Arrhenius published the first calculation of global warming from human-induced emissions of carbon dioxide.


      British scientist Thomas C. Chamberlin established the link between ice ages and low concentrations of carbon dioxide and between warm climates and high concentrations of carbon dioxide.


      The opening of Texas and Persian Gulf oil fields inaugurated an era of cheap energy. The burning of petroleum releases greenhouse gases into the atmosphere, warming the climate.


      German climatologist and geologist Alfred Wegener posited that the continents move slowly across the Earth. When they are near the equator their climate is warm, while near the poles their climate is cold.


      Serbian geophysicist Milutin Milankovitch proposed that changes in the eccentricity of the Earth's orbit cause climate change, including ice ages.


      The first successful oil well was drilled in the east Texas oil fields.


      Meteorologist W. J. Humphreys elaborated the conditions for a return to an ice age. He believed that an increase in debris in the atmosphere and the reflection of sunlight by ice and snow might return the Earth to an ice age.


      The drought of the 1930s created dust storms on the Plains. The worst dust storm of the Dust Bowl gripped the Plains on what later became known as Black Sunday. President Franklin Roosevelt established the Soil Erosion Service in response to the devastation of the Dust Bowl and as a part of his New Deal programs to create jobs. The Soil Erosion Service was the predecessor of the Soil Conservation Service established in 1935, which is known today as the Natural Resources Conservation Service (NCRS).


      Royal Meteorological Society president George Simpson posited that an increase in solar radiation might cause an ice age. By warming the poles more than high altitudes, the increase in solar radiation would intensify the circulation of the atmosphere, carrying moisture to high latitudes, where it would fall as snow. If enough snow accumulated, a new ice age would ensue.


      Amateur scientist G. S. Callendar recorded an increase in temperatures in the Arctic and posited the greenhouse effect as the cause.


      Oil was discovered in Saudi Arabia and eventually transformed the country from one of the poorest to one of the richest in the world.


      Simpson announced that the atmosphere seems to keep the climate nearly constant by regulating the amount of clouds. The more clouds the lower the temperature, and the fewer clouds the warmer the temperature.


      Many scientists dismissed Callendar's claims. However, in response to his theory scientists began to develop new ways to measure the history of and current conditions of the Earth's climate.


      The world's largest pipeline was built to transport oil from the east Texas oil fields to Philadelphia where it was refined.


      The U.S. Office of Naval Research began generous funding of many fields of science, some of them useful for understanding climate change.


      The Bulletin of the Atomic Scientists established the Doomsday Clock, a symbol of how close they feel the world is to disaster (the closer to midnight, the nearer to disaster). Originally, the clock was established to symbolize the threat of global nuclear war, but it currently reflects the estimation of other threats, including those posed by global warming.


      The development of new technology led to an increased awareness of global warming and the greenhouse effect. Researchers began to show that the level of carbon dioxide in the atmosphere was rising each year and people became concerned about pollution.


      American scientist Charles F. Brooks announced that Arctic ice might be melting and that, once started, the melting might shrink the ice to a vestige of its former size and raise sea levels.


      American scientists Maurice Ewing and William Donn posited that the last ice age rapidly descended on the Earth when the North Pole wandered into the Arctic Ocean, triggering the accumulation of snow and ice in this region. American scientist Norman Phillips produced a somewhat realistic computer model of the global atmosphere. Canadian physicist Gilbert Plass calculated that adding carbon dioxide to the atmosphere would affect the radiation balance.


      Launch of the Soviet Union's Sputnik satellite. Cold war concerns dominate the 1957–58 International Geophysical Year, bringing new funding and coordination to climate studies. U.S. oceanographer Roger Revelle warned that humanity is conducting a “large-scale geophysical experiment” on the planet by releasing greenhouse gases.


      Astronomers identified the greenhouse effect on Venus, where temperatures are far above the boiling point of water.


      A report found that global temperatures had declined since the early 1940s. American scientist Charles David Keeling set up the first continuous monitoring of carbon dioxide levels in the atmosphere. Keeling soon found a regular rise in temperatures.


      Soviet meteorologist Mikhail Budyko warned that the burning of fossil fuels and the attendant accumulation of greenhouse gases in the atmosphere would warm the planet.


      Fritz Moller calculated that a doubling of carbon dioxide in the atmosphere might increase temperatures 50 degrees F (28 degrees C).


      Climatologists gathered in Boulder, Colorado, to discuss climate change. Edward Lorenz and others pointed out the chaotic nature of the climate system and the possibility of sudden shifts.


      Italian scientist Cesare Emiliani's analysis of deepsea cores showed that the timing of ice ages was set by small orbital shifts, suggesting that the climate system is sensitive to small changes.


      The International Global Atmospheric Research Program was established, mainly to gather data for better short-range weather prediction. Computer modelers Syukuro Manabe and Richard Wetherald predicted that an increase in the number of clouds might hold heat in the atmosphere and therefore increase temperatures.


      Budyko derived two mathematical models. One predicted an increase in temperatures due to the greenhouse effect. The other predicted the return of the ice age. Budyko favored the first model. Other models were also contradictory. Studies suggested that the Antarctic ice sheet might collapse, raising sea levels catastrophically.


      American climatologist William Sellers predicted that a 2 percent decrease in solar radiation, whether from a fluctuation in solar output or the result of debris in the air, might plunge the Earth into a new ice age. Like Budyko, Sellers feared that the burning of fossil fuels might warm the Earth. The Nimbus III satellite began to provide comprehensive global atmospheric temperature measurements.


      The first Earth Day was held. The environmental movement attained strong influence, spreading concern about global degradation. The creation of the U.S. National Oceanic and Atmospheric Administration, the world's leading funder of climate research. Aerosols from human activity were increasing in the atmosphere. American scientist Reid Bryson claimed that they counteracted global warming and may actually cool the Earth.


      The Study of Man's Impact on Climate (SMIC), a conference of leading scientists, reported a danger of rapid and serious global change caused by humans and called for an organized research effort. The American Mariner 9 spacecraft found a great dust storm warming the atmosphere of Mars, along with indications of a radically different climate in the planet's past.


      Budyko predicted that a 50 percent increase in greenhouse gases in the atmosphere might raise temperatures enough to melt all the ice on Earth, whereas a 50 percent reduction might plunge the Earth into an ice age. Budyko favored the first scenario and predicted that temperatures might rise enough to melt all the ice by 2050. Ice cores and other evidence showed that the climate changed in the past in the space of 1,000 years or so, especially around 11,000 years ago.


      Serious droughts and other unusual weather since 1972 increased scientific and public concern about climate change, with cooling from aerosols suspected to be as likely as warming. Journalists wrote about ice ages.


      Concern about the environmental effects of airplanes led to investigations of trace gases in the stratosphere and the discovery of danger to the ozone layer. Manabe and collaborators produced complex, but plausible computer models that predicted an increase of several degrees Fahrenheit for a doubling of carbon dioxide.


      Studies showed that chlorofluorocarbons (CFCs) (1975) and also methane and ozone (1976) contribute to the greenhouse effect. Deep-sea cores showed a dominating influence from 100,000 years ago. Milankovitch's prediction of orbital

      changes emphasized the role of feedbacks. Deforestation and other ecosystem changes were recognized as major factors in the future of the climate. American meteorologist Amos Eddy showed that the absence of sunspots in past centuries corresponded with cold periods.


      Scientific opinion tended to converge on global warming, not cooling, as the chief climatic risk in the next century.


      Attempts to coordinate climate research in the United States ended with an inadequate National Climate Program Act, accompanied by rapid, but temporary growth in funding. American scientist James Hansen predicted that the accumulation of aerosol particles in the atmosphere might reflect sunlight back into space and therefore reduce temperatures.


      A strengthened environmental movement encouraged the development of renewable energy sources and the reduction of technologies that burn fossil fuels. The U.S. National Academy of Sciences estimated that a doubling of carbon dioxide might increase temperatures 35 to 40 degrees F (19 to 22 degrees C). The World Climate Research Program was launched to coordinate international research on climate change.


      The election of President Ronald Reagan caused a backlash against the environmental movement. Political conservatism was linked to skepticism about global warming. Some scientists predicted that greenhouse warming should be measurable by about 2000.


      Greenland ice cores revealed temperature oscillations over a single century in the distant past. Strong global warming since the mid-1970s was reported, with 1981 the warmest year on record.


      Reports from the U.S. National Academy of Sciences and the Environmental Protection Agency spark conflict, as greenhouse warming becomes prominent in mainstream politics.


      Theories about global warming and the greenhouse effect became more prevalent, gaining attention from the mass media. However, many people believed that the threat was not imminent and some doubted that global climate change was a danger.


      Center for Atmospheric Science Director Veer-abhadran Ramanathan and collaborators announced that methane and other trace gases together could bring about as much global warming as carbon dioxide. The Villach conference in Indonesia declared consensus among experts that some global warming seems inevitable and called on governments to consider international agreements to restrict emissions of greenhouse gases. Antarctic ice cores showed that carbon dioxide and temperature went up and down together through past ice ages, pointing to powerful biological and geochemical feedbacks. American scientist Wallace Broecker speculated that a reorganization of North Atlantic Ocean circulation could bring swift and radical climate change.


      This was the warmest year since humans began to keep records. The 1980s were the hottest decade on record, with seven of the eight warmest years recorded up to 1990. Even the coldest years in the 1980s were warmer than the warmest years of the 1880s. The Montreal Protocol of the Vienna Convention imposed international restrictions on the emission of ozone-destroying gases.


      Global warming attracts worldwide headlines after scientists at congressional hearings in Washington, D.C., blamed the U.S. drought on its influence. A meeting of climate scientists in Toronto subsequently called for 20 percent cuts in global carbon dioxide emissions by 2005. The United Nations set up the Intergovernmental Panel on Climate Change (IPCC) to analyze and report on scientific findings. News media coverage of global warming leapt upward following record heat and droughts. The Toronto conference called for strict, specific limits on greenhouse gas emissions. British Prime Minister Margaret Thatcher was the first major leader to call for action. Ice-core and biology studies confirmed that living ecosystems give climate feedback by way of methane, which could accelerate global warming. The level of carbon dioxide in the atmosphere reached 350 parts per million.


      Fossil-fuel suppliers and other industries formed the Global Climate Coalition in the United States to lobby politicians and convince the media and public that climate science is too uncertain to justify action.


      American meteorologist Richard Lindzen predicted that an increase in carbon dioxide in the atmosphere might not cause a concomitant increase in water vapor. Consequently, the greenhouse effect might be less severe than some were forecasting. The first IPCC report stated that the world had been warming and continued warming seemed likely in the future. Industry lobbyists and some scientists disputed the tentative conclusions.


      Mount Pinatubo erupted. Hansen predicted that the eruption would cool the Earth, verifying (by 1995) computer models of aerosol effects. Global warming skeptics emphasized research indicating that a significant part of 20th-century temperature change was due to solar influences. Studies from 55 million years ago show the possibility of the eruption of methane from the seabed, causing enormous warming.


      A conference in Rio de Janeiro produced the United Nations Framework Convention on Climate Change, but the United States blocked calls for serious action. The study of ancient climates revealed climate sensitivity in the same range as predicted by computer models.


      Greenland ice cores suggested that great climate changes (at least on a regional scale) could occur in the timespan of a single decade.


      The second IPCC report detected the “signature” of human-caused greenhouse effect warming, declaring that serious warming was likely in the coming century. Reports of the breaking up of the Antarctic ice sheet and other signs of current warming in polar regions affected public opinion.


      Japanese automobile manufacturer Toyota introduced the Prius in Japan, the first mass-marketed electric hybrid car. Engineers progressed in the design of large wind turbines and other energy alternatives. An international conference in Japan produced the Kyoto Protocol, setting targets to reduce greenhouse gas emissions—if enough nations approved and signed the treaty.


      The warmest year on record globally averaged (1995, 1997, and 2001–06 were near the same level). Borehole data confirmed an extraordinary warming trend. Qualms about arbitrariness in computer models diminished as teams modeled ice-age climate and dispensed with special adjustments to reproduce current climate.


      The LEED (Leadership in Energy and Environmental Design) green building rating system was introduced by the U.S. Green Building Council.


      A National Academy panel dismissed criticism that satellite measurements showed no warming. Ramanathan detected a massive “brown cloud” of aerosols from south Asia.


      The Global Climate Coalition dissolved as many corporations grappled with the threat of warming, but the oil lobby convinced the U.S. administration to deny the problem. Various studies emphasized variability and the importance of biological feedbacks in the carbon cycle that are liable to accelerate warming.


      The third IPCC report stated that global warming, unprecedented since the end of the last ice age, is “very likely,” with possible severe surprises. The National Academy panel marked a “paradigm shift” in scientific recognition of the risk of abrupt climate change (decade-scale). Warming is observed in ocean basins. These observations match computer models, giving a clear signature of the greenhouse effect.


      Signatories to the Kyoto Protocol, minus the United States, opened the way to ratification by agreeing on the treaty's rulebook.


      Studies found surprisingly strong “global dimming,” due to pollution. This factor had retarded greenhouse warming, but dimming is now decreasing.


      Numerous observations raised concern that the collapse of ice sheets (west Antarctica, Greenland) might raise sea levels faster than most had believed. A deadly summer heat wave in Europe deepened divergence between European and U.S. public opinion.


      The first certified green residential high-rise building in the United States, The Solaire, was built in New York City. Certified LEED (Leadership in Energy and Environmental Design) Gold, the Solaire included a greywater system, photovoltaic cells, and two green roofs.


      In a controversy over temperature data covering the past millennium, most scientists concluded that climate variations were substantial, but not comparable to post–1980 warming. The first major books, movies, and artwork featured global warming.


      California became the first U.S. state to adopt regulations intended to reduce greenhouse gas emissions. These regulations, which have since been adopted by other states, included requirements that 2012 model-year automobiles reduce emissions by 22 percent.


      Due to increased use of fossil fuels, the International Energy Agency declared China to be the second-largest carbon emitter in the world.


      The Kyoto Treaty, signed by all major industrial nations except the United States, took effect. Work to retard greenhouse emissions accelerated in Japan, western Europe, U.S. regional governments, and corporations. Hurricane Katrina and other major tropical storms spurred debate over the impact global warming had on storm intensity.


      New York City passed a law requiring that most new buildings meet LEED (Leadership in Energy and Environmental Design) green building standards.


      An Inconvenient Truth premiered at the 2006 Sundance Film Festival and opened in New York and Los Angeles on May 24, 2006, earning $49 million. It went on to win Academy Awards for Best Documentary and Best Original Song.


      The first LEED (Leadership in Energy and Environmental Design) platinum-rated government office building in the United States opens: the Lewis and Clark State Office Building in Jefferson City, Missouri.


      A report by Sir Nicholas Stern, former economist for the World Bank, stated that if unchecked, global warming may come to consume up to 20 percent of global gross domestic product.


      The fourth IPCC report warned that serious effects of warming had become evident. The cost of reducing emissions would be far less than the damage they will cause. Former Vice President Al Gore shared the Nobel Peace Prize for his efforts to spread knowledge about global warming. The level of carbon dioxide in the atmosphere reached 382 parts per million.


      Studies revealed that ice sheets in Greenland and Antarctica were shrinking faster than expected, as was the sea ice cover in the Arctic Ocean.


      The Bulletin of the Atomic Scientists subtracted two minutes from the Doomsday Clock, signifying their belief that climate change as well as nuclear proliferation were moving humanity closer to disaster.


      The e-mail system at the University of East Anglia in the United Kingdom was hacked and documents and messages from researchers at that university's Climate Research Center seemed to raise questions about evidence for global warming. Although these charges were refuted by scientists who study global warming, the incident, dubbed “Climate-Gate” in the popular press, was taken by some climate change skeptics as evidence that scientists could not be trusted.


      An international consortium of scientists declared that the global warming predictions contained in a 2007 IPPC (International Panel on Climate Change) report were occurring more rapidly than expected.


      The five-year average global temperature was 58.1 degrees F (31.9 degrees C), the warmest in hundreds, if not thousands of years. By way of comparison, it was estimated at 56.5 degrees F (31 degree C) in the mid-19th century and 57 degrees F (31.3 degrees C) in 1960.


      The measured level of carbon dioxide in the atmosphere was 385 parts per million (versus 315 parts per million in 1960).


      The Copenhagen Summit, also known as the United Nations Climate Change Conference, produced the Copenhagen Accord, which recognized the danger of climate change but did not include binding commitments to reduce greenhouse emissions.


      Nature published research by Damon Matthews and colleagues that demonstrated a simple linear relationship historically between global warming and carbon dioxide emissions.


      The Bulletin of the Atomic Scientists added one minute to the Doomsday Clock, signifying that they believed the world had taken important steps to limit the effects of climate change.


      A study published in Science attributed decreased agricultural production over the past 28 years in part to global warming and predicted that such effects will intensify as the climate becomes warmer. The report also noted that global warming had increased yields in some areas, moderating the overall negative effect on production.


      The World Bank created a program to stimulate creation of clean energy projects and slow destruction of tropical forests in developing countries.


      Research from the University of Exeter, published in the Proceedings of the National Academy of Sciences, predicted that 1 in 10 species on Earth face extinction if global warming continues at its current pace.


      A report in Nature Geoscience suggested that global warming is reducing the ability of the world's oceans to act as a carbon sink, threatening its ability to act as a buffer against future climate change.


      The American Association for the Advancement of Science reported threats ranging from intimidation and legal harassment to death threats against researchers studying global warming.


      A study found that the temperature of the Arctic Ocean was 3.5 degrees F (2 degrees C) higher than it was 100 years ago, and 2.5 degrees F (1.4 degrees C) warmer than it was during the Medieval Warm Period of 900–1300.


      Furthering the ongoing debate, the global warming stance taken by the by the National Aeronautics and Space Administration (NASA) was attacked in a letter by 49 former NASA scientists and astronauts, citing unwarranted claims about the role of human-made carbon dioxide in global warming. Yet 98 percent of working climate scientists express concern about the role of carbon dioxide in climate change.

      ChristopherCumoIndependent Scholar
      FernandoHerreraUniversity of California, San Diego
    • Glossary

      Abrupt Climate Change

      A change in the climate that takes place over a few decades or less, persists for at least a few decades, and causes substantial disruptions in human and natural systems.

      Acid Rain

      Also called acid precipitation or acid deposition, acid rain is precipitation containing harmful amounts of nitric and sulfuric acids formed primarily by sulfur dioxide and nitrogen oxides released into the atmosphere when fossil fuels are burned. It can be wet precipitation (rain, snow, or fog) or dry precipitation (absorbed gaseous and particulate matter, aerosol particles, or dust). Acid rain has a pH below 5.6. Normal rain has a pH of about 5.6, which is slightly acidic. The term pH is a measure of acidity or alkalinity and ranges from 0 to 14. A pH measurement of 7 is regarded as neutral. Measurements below 7 indicate increased acidity, while those above 7 indicate increased alkalinity.


      Adjustment in natural or human systems to a new or changing environment. Adaptation to climate change refers to adjustment in natural or human systems in response to actual or expected climatic stimuli or their effects, which moderates harm or exploits beneficial opportunities. Various types of adaptation can be distinguished, including anticipatory and reactive adaptation, private and public adaptation, and autonomous and planned adaptation.


      A collection of airborne solid or liquid particles, with a typical size between 0.01 and 10 micrometers (μm) and residing in the atmosphere for at least several hours. Aerosols may be of either natural or anthropogenic origin. Aerosols may influence climate in two ways: directly through scattering and absorbing radiation, and indirectly through acting as condensation nuclei for cloud formation or modifying the optical properties and lifetime of clouds.


      The practice of restoring and re-creating of non-forest land to a new forest, or restoring a forest that was deforested many years ago from human activities, such as agriculture or habitation.


      The fraction of solar radiation reflected by a surface or object, often expressed as a percentage. Most snow-covered surfaces have a high albedo; the albedo of soils ranges from high to low; vegetation-covered surfaces and oceans have a low albedo. The Earth's albedo varies mainly through varying cloudiness, snow, ice, leaf area, and land cover changes.


      A village in Denmark; its name is used for a warm period at the end of the last glacial period.

      Alliance of Small Island States (AOSIS)

      The group of Pacific and Caribbean nations that call for relatively fast action by developed nations to reduce greenhouse gas emissions. The AOSIS countries fear the effects of rising sea levels and increased storm activity predicted to accompany global warming. Its plan is to hold Annex I Parties to a 20 percent reduction in carbon dioxide emissions by 2005.

      Alternative Energy

      Energy derived from nontraditional sources (e.g., compressed natural gas, solar, hydroelectric, and wind).

      Annex I Parties

      Industrialized countries that, as parties to the Framework Convention on Climate Change, have pledged to reduce their greenhouse gas emissions by 2000 to 1990 levels. Annex I Parties consist of countries belonging to the Organisation for Economic Co-operation and Development (OECD) and countries designated as economies in transition.


      Made by people or resulting from human activities. Usually used in the context of emissions that are produced as a result of human activities.


      The gaseous envelope surrounding the Earth. The dry atmosphere consists almost entirely of nitrogen (78.1 percent volume mixing ratio) and oxygen (20.9 percent volume mixing ratio), together with a number of trace gases, such as argon (0.93 percent volume mixing ratio), helium, radiatively active greenhouse gases such as carbon dioxide (0.035 percent volume mixing ratio), and ozone. In addition, the atmosphere contains water vapor, the amount of which is highly variable but typically 1 percent volume mixing ratio. The atmosphere also contains clouds and aerosols. The atmosphere can be divided into a number of layers according to its mixing or chemical characteristics, generally determined by its thermal properties (temperature). The layer nearest the Earth is the troposphere, which reaches up to an altitude of about about 5 mi. (8 km) in the polar regions and up to nearly 11 mi. (17 km) above the equator. The stratosphere, which reaches to an altitude of about 31 mi. (50 km), lies atop the troposphere. The mesosphere, which extends up to 50–56 mi. (80–90 km), is atop the stratosphere, and finally the thermosphere, or ionosphere, gradually diminishes and forms a fuzzy border with outer space.

      Atmospheric Lifetime

      The lifetime of a greenhouse gas refers to the approximate amount of time it would take for the anthropogenic increment to an atmospheric pollutant concentration to return to its natural level (assuming emissions cease) as a result of either being converted to another chemical compound or being taken out of the atmosphere via a sink. This time depends on the pollutant's sources and sinks as well as its reactivity. The lifetime of a pollutant is often considered in conjunction with the mixing of pollutants in the atmosphere; a long lifetime will allow the pollutant to mix throughout the atmosphere. Average lifetimes can vary from about a week (sulfate aerosols) to more than a century (chlorofluorocarbons [CFCs] and carbon dioxide).

      Baseline Emissions

      The emissions that would occur without policy intervention (in a business-as-usual scenario). Baseline estimates are needed to determine the effectiveness of emissions reduction programs.

      Basket of Gases

      The basket of gases includes six greenhouse gases, which are: carbon dioxide (CO2), nitrous oxide (N2O), perfluorocarbons (PFCs), methane (CH4), hydrofluorocarbons (HFCs), and sulfur hexafluoride (SF6). These six greenhouse gases are regulated under the Kyoto Protocol.

      Berlin Mandate

      A ruling negotiated at the first Conference of the Parties (COP 1), which took place in March, 1995, concluding that the present commitments under the Framework Convention on Climate Change are not adequate. Under the Framework Convention, developed countries pledged to take measures aimed at returning their greenhouse gas emissions to 1990 levels by 2000.

      Biogeochemical Cycle

      The chemical interactions that take place among the key chemical constituents essential to life, such as carbon, nitrogen, oxygen, and phosphorus.


      Organic non-fossil materials that are biological in origin, including organic material (both living and dead) from above and below ground (e.g., trees, plants, crops, roots, animals, and animal waste).

      Biomass Energy

      Energy produced by combusting renewable biomass materials such as wood. The carbon dioxide emitted from burning biomass will not increase total atmospheric carbon dioxide if this consumption is done on a sustainable basis (i.e., if in a given period of time, regrowth of biomass takes up as much carbon dioxide as is released from biomass combustion). Biomass energy is often suggested as a replacement for fossil fuel combustion, which produces large greenhouse gas emissions.


      The part of the Earth system comprising all ecosystems and living organisms in the atmosphere, on land (terrestrial biosphere), or in the oceans (marine biosphere), including derived dead organic matter such as litter, soil organic matter, and oceanic detritus.

      Black Carbon

      Operationally defined species based on measurement of light absorption and chemical reactivity and/or thermal stability; consists of soot, charcoal, and/or possible light-absorbing refractory organic matter.


      Any exploratory hole drilled into the Earth or ice to gather geophysical data. Climate researchers often take ice core samples, a type of borehole, to predict atmospheric composition in earlier years.

      Capital Stocks

      The accumulation of machines and structures that are available to an economy at any point in time to prune goods or render services. These activities usually require a quantity of energy that is determined largely by the rate at which that machine or structure is used.

      Carbon Cycle

      All parts (reservoirs) and fluxes of carbon. The cycle is usually thought of as four main reservoirs of carbon interconnected by pathways of exchange. The reservoirs are the atmosphere, terrestrial biosphere (usually includes freshwater systems), oceans, and sediments (includes fossil fuels). The annual movements of carbon, the carbon exchanges between reservoirs, occur because of various chemical, physical, geological, and biological processes. The ocean contains the largest pool of carbon near the surface of the Earth, but most of that pool is not involved with rapid exchange with the atmosphere.

      Carbon Dioxide (CO2)

      The concentration of this greenhouse gas is affected directly by human activities. CO2 also serves as the reference to compare all other greenhouse gases. The major source of CO2 emissions is fossil fuel combustion. CO2 emissions are also a product of forest clearing, biomass burning, and non-energy production processes such as cement production. Atmospheric concentrations of CO2 have been increasing at a rate of about 0.5 percent per year and are now about 30 percent above preindustrial levels.

      Carbon Dioxide Equivalent

      A metric measure used to compare the emissions of the different greenhouse gases based upon their global warming potential (GWP). Carbon dioxide equivalents are commonly expressed as “million metric tons of carbon dioxide equivalents (MMT-CO2Eq).” The carbon dioxide equivalent for a gas is derived by multiplying the tons of the gas by the associated GWP. The use of carbon equivalents (MMTCE) is declining.

      Carbon Dioxide Fertilization

      The enhancement of the growth of plants as a result of increased atmospheric CO2 concentration. Depending on their mechanism of photosynthesis, certain types of plants are more sensitive to changes in atmospheric CO2 concentration. In particular, C3 plants generally show a larger response to CO2 than C4 plants.

      Carbon Sequestration

      The uptake and storage of carbon. Trees and plants, for example, absorb carbon dioxide, release the oxygen, and store the carbon. Fossil fuels were at one time biomass and continue to store the carbon until burned.

      Carbon Sinks

      Carbon reservoirs and conditions that take in and store more carbon (carbon sequestration) than they release. Carbon sinks can serve to partially offset greenhouse gas emissions. Forests and oceans are common carbon sinks.

      Chlorofluorocarbons and Related Compounds

      This family of anthropogenic compounds includes chlorofluorocarbons (CFCs), bromofluorocarbons (halons), methyl chloroform, carbon tetrachloride, methyl bromide, and hydrochlorofluorocarbons (HCFCs). These compounds have been shown to deplete stratospheric ozone, and therefore are typically referred to as ozone-depleting substances. The most ozone-depleting of these compounds are being phased out under the Montreal Protocol.


      Climate in a narrow sense is usually defined as the “average weather,” or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands of years. The classical period is three decades, as defined by the World Meteorological Organization (WMO). These quantities are most often surface variables such as temperature, precipitation, and wind. Climate in a wider sense is the state, including a statistical description, of the climate system.

      Climate Change

      Climate change refers to any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). Climate change may result from natural factors, such as changes in the sun's intensity or slow changes in the Earth's orbit around the sun; natural processes within the climate system (e.g., changes in ocean circulation); human activities that change the atmosphere's composition (e.g., through burning fossil fuels); and the land surface (e.g., deforestation, reforestation, urbanization, and desertification).

      Climate Change Action Plan (CCAP)

      Unveiled in October 1993 by President Clinton, the CCAP is the U.S. plan for meeting its pledge to reduce greenhouse gas emissions under the terms of the Framework Convention on Climate Change (FCCC). The goal of the plan was to reduce U.S. emissions of greenhouse gases to 1990 levels by 2000.

      Climate Feedback

      An interaction mechanism between processes in the climate system is called a climate feedback, when the result of an initial process triggers changes in a second process that in turn influences the initial one. A positive feedback intensifies the original process, and a negative feedback reduces it.

      Climate Lag

      The delay that occurs in climate change as a result of some factor that changes only very slowly.

      Climate Model

      A quantitative way of representing the interactions of the atmosphere, oceans, land surface, and ice.

      Climate Modeling

      The simulation of the climate using computer-based models.

      Climate Sensitivity

      The equilibrium response of the climate to a change in radiative forcing; for example, a doubling of the carbon dioxide concentration.

      Climate System (or Earth System)

      The five physical components (atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere) that are responsible for the climate and its variations.

      Cloud Condensation Nuclei

      Cloud condensation nuclei are more commonly known as cloud seeds. These airborne particles are transformed from gas state to liquid state through the process of condensation, and potentially form cloud droplets.

      Coalbed Methane (CBM)

      Coalbed methane is methane contained in coal seams, and is often referred to as virgin coalbed methane, or coal seam gas.

      Coal Mine Methane

      Coal mine methane is the subset of CBM that is released from coal seams during the process of coal mining.

      Conference of the Parties (COP)

      The supreme body of the United Nations Framework Convention on Climate Change (UNFCCC). It comprises more than 180 nations that have ratified the convention. Its first session was held in Berlin, Germany, in 1995, and it is expected to continue meeting on a yearly basis. The COP's role is to promote and review the implementation of the convention.

      Coral Bleaching

      The process that takes place when corals lose the microscopic organisms called algae that live within their tissues. These algae provide the coral with nutrients, and they're responsible for the color of the coral. If a disturbance such as rising water temperature causes the algae to leave, corals will appear white and could eventually die.


      One of the interrelated components of the Earth's system, the cryosphere is frozen water in the form of snow, permanently frozen ground (permafrost), floating ice, and glaciers. Fluctuations in the volume of the cryosphere cause changes in ocean sea level, which directly impact the biosphere.


      Those practices or processes that result in the change of forested lands to nonforest uses. This is often cited as one of the major causes of the enhanced greenhouse effect for two reasons: (1) the burning or decomposition of the wood releases carbon dioxide; and (2) trees that once removed carbon dioxide from the atmosphere in the process of photosynthesis are no longer present and contributing to carbon storage.


      Land degradation in arid, semi-arid, and dry sub-humid areas resulting from various factors, including climatic variations and human activities.

      Diurnal Temperature Range (DTR)

      The diurnal temperature range is determined by calculating the difference between the minimum and maximum temperatures during a 24-hour period.

      Economic Potential

      The portion of the technical potential for greenhouse gas emissions reductions or energy-efficiency improvements that could be achieved cost-effectively in the absence of market barriers. The achievement of the economic potential requires additional policies and measures to break down market barriers.


      A natural community of plants, animals, and other living organisms and the physical environment in which they live and interact.

      El Niño

      A climatic phenomenon occurring irregularly, but generally every three to five years. El Niños often first become evident during the Christmas season (El Niño means Christ-child) in the surface oceans of the eastern tropical Pacific Ocean. The phenomenon involves seasonal changes in the direction of the tropical winds over the Pacific and abnormally warm surface ocean temperatures. The changes in the tropics are most intense in the Pacific region; these changes can disrupt weather patterns throughout the tropics and can extend to higher latitudes.


      The release of a substance (usually a gas when referring to climate change) into the atmosphere.

      Energy Vampire

      An appliance or device that uses electricity even when it is turned off.

      Enhanced Greenhouse Effect

      The natural greenhouse effect has been enhanced by anthropogenic emissions of greenhouse gases. Increased concentrations of carbon dioxide, methane, nitrous oxide, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HFCs), perfluorocar-bons (PFCs), sulfur hexafluoride (SF6), nitrogen trifluoride (NF3), and other photochemically important gases caused by human activities such as fossil fuel consumption trap more infrared radiation, thereby exerting a warming influence on the climate.


      The sum of evaporation and plant transpiration. Potential evapotranspiration is the amount of water that could be evaporated or transpired at a given temperature and humidity, if there was water available. Actual evapotranspiration can not be any greater than precipitation, and will usually be less because some water will run off in rivers and flow to the oceans. If potential evapotranspiration is greater than actual precipitation, then soils are extremely dry during at least a major part of the year.

      Fluorinated Gas

      A group of powerful greenhouse gases that can stay in the atmosphere for hundreds to thousands of years. Fluorinated gases are manmade; they do not occur naturally. They are used in refrigeration and air-conditioning systems, fire extinguishers, and foam products.


      Carbon-fluorine compounds that often contain other elements such as hydrogen, chlorine, or bromine. Common fluorocarbons include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs).

      Forcing Mechanism

      A process that alters the energy balance of the climate system, that is, changes the relative balance between incoming solar radiation and outgoing infrared radiation from Earth. Such mechanisms include changes in solar irradiance, volcanic eruptions, and enhancement of the natural greenhouse effect by emissions of greenhouse gases.

      Fossil Fuel

      A type of fuel that forms deep within the Earth. Examples of fossil fuels include coal, oil, and natural gas. Fossil fuels are created over millions of years as dead plant and animal material becomes trapped and buried in layers of rock, and heat and pressure transform this material into a fuel. All fossil fuels contain carbon, and when people burn these fuels to produce energy, they create carbon dioxide.

      General Circulation Model (GCM)

      A global, three-dimensional computer model of the climate system that can be used to simulate human-induced climate change. GCMs are highly complex and they represent the effects of such factors as reflective and absorptive properties of atmospheric water vapor, greenhouse gas concentrations, clouds, annual and daily solar heating, ocean temperatures, and ice boundaries. The most recent GCMs include global representations of the atmosphere, oceans, and land surface.


      A multi-year surplus accumulation of snowfall in excess of snowmelt on land and resulting in a mass of ice at least 0.1 km2 in area that shows some evidence of movement in response to gravity. A glacier may terminate on land or in water. Glaciers are on every continent except Australia.

      Global Warming

      Global warming is an average increase in the temperature of the atmosphere near the Earth's surface and in the troposphere, which can contribute to changes in global climate patterns. Global warming can occur from many causes, both natural and human induced.

      Global Warming Potential (GWP)

      Global warming potential is the cumulative radiative forcing effects of a gas over a specified time horizon resulting from the emission of a unit mass of gas relative to a reference gas. The GWP-weighted emissions of direct greenhouse gases in the U.S. inventory are presented in terms of equivalent emissions of carbon dioxide (CO2), using units of teragrams of carbon dioxide equivalents (TgCO2Eq.).

      The molecular weight of carbon is 12, and the molecular weight of oxygen is 16; therefore, the molecular weight of CO2 is 44 (i.e., 12+[16 × 2]), as compared to 12 for carbon alone. Thus, carbon comprises 12/44ths of carbon dioxide by weight.

      Greenhouse Effect

      Trapping and buildup of heat in the atmosphere (troposphere) near the Earth's surface. Some of the heat flowing back into space from the Earth's surface is absorbed by water vapor, carbon dioxide, ozone, and several other gases in the atmosphere and then reradiated back toward the Earth's surface. If the atmospheric concentrations of these greenhouse gases rise, the average temperature of the lower atmosphere will gradually increase.

      Greenhouse Gas (GHG)

      Any gas that absorbs infrared radiation in the atmosphere. Greenhouse gases include, but are not limited to, water vapor, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), chloro-fluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), ozone (O3), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6)


      Compounds containing either chlorine, bromine, or fluorine and carbon. Such compounds can act as powerful greenhouse gases in the atmosphere. The chlorine and bromine containing halocarbons are also involved in the depletion of the ozone layer.

      Heterotrophic Respiration

      Organic matter that is converted to CO2 by organisms other than plants.

      Hockey Stick

      A plot of the past millennium's temperature that shows the drastic influence of humans in the 20th century. Specifically, temperature remains essentially flat until about 1900, then shoots up, like the upturned handle of a hockey stick.


      Hydrocarbons are substances containing only hydrogen and carbon. Fossil fuels are made up of hydrocarbons.

      Hydrochlorofluorocarbons (HCFCs)

      Compounds containing hydrogen, fluorine, chlorine, and carbon atoms. Although ozone-depleting substances, they are less potent at destroying stratospheric ozone than chlorofluorocarbons (CFCs). They have been introduced as temporary replacements for CFCs and are also greenhouse gases.

      Hydrologic Cycle

      The process of evaporation, vertical and horizontal transport of vapor, condensation, precipitation, and the flow of water from continents to oceans. It is a major factor in determining climate through its influence on surface vegetation, the clouds, snow and ice, and soil moisture. The hydrologic cycle is responsible for 25 to 30 percent of the midlatitudes’ heat transport from the equatorial to polar regions.


      The component of the climate system comprising liquid surface and subterranean water, such as oceans, seas, rivers, freshwater lakes, and underground water.

      Ice Cap

      A dome-shaped accumulation of glacier ice and perennial snow that completely covers a mountainous area or island, so that no peaks or nunataks poke through.

      Ice Core

      A cylindrical section of ice removed from a glacier or an ice sheet in order to study climate patterns of the past. By performing chemical analyses on the air trapped in the ice, scientists can estimate the percentage of carbon dioxide and other trace gases in the atmosphere at a given time.

      Ice Sheet

      A thick, subcontinental- to continental-scale accumulation of glacier ice and perennial snow that spreads from a center of accumulation, typically in all directions. Also called a continental glacier.

      Ice Shelf

      The floating terminus of a glacier, typically formed when a terrestrial glacier flows into a deep water basin, such as in Antarctica and the Canadian Arctic.

      Infrared Radiation

      Radiation emitted by the Earth's surface, the atmosphere, and clouds. It is also known as terrestrial or longwave radiation. Infrared radiation has a distinctive range of wavelengths longer than the wavelength of the red color in the visible part of the spectrum of infrared radiation. It is practically distinct from that of solar or short-wave radiation because of the difference in temperature between the sun and the Earth-atmosphere system.

      Intergovernmental Panel on Climate Change (IPCC)

      The IPCC was established jointly by the United Nations Environment Programme and the World Meteorological Organization in 1988. The purpose of the IPCC is to assess information in the scientific and technical literature related to all significant components of the issue of climate change. The IPCC draws upon hundreds of the world's expert scientists as authors and thousands as expert reviewers. Leading experts on climate change and environmental, social, and economic sciences from some 60 nations have helped the IPCC to prepare periodic assessments of the scientific underpinnings for understanding global climate change and its consequences. With its capacity for reporting on climate change, its consequences, and the viability of adaptation and mitigation measures, the IPCC is also looked to as the official advisory body to the world's governments on the state of the science of the climate change issue. For example, the IPCC organized the development of internationally accepted methods for conducting national greenhouse gas emission inventories.


      Land waste disposal site in which waste is generally spread in thin layers, compacted, and covered with a fresh layer of soil each day.

      Level of Scientific Understanding (LOSU)

      Level of Scientific Understanding is a subjective, four-point scale ranging from very low, to low, to medium, to high. The LOSU is intended to differentiate the level of scientific understanding of the radiative forcing agents that influence climate change.

      Longwave Radiation

      The radiation emitted in the spectral wavelength greater than 4 micrometers corresponding to the radiation emitted from the Earth and atmosphere.

      Mauna Loa Record

      The Mauna Loa Observatory in Mauna Loa, Hawai'i, has been collecting atmospheric CO2 concentration data since 1958 and this data is called the Mauna Loa record. This record shows that the average yearly atmospheric CO2 concentrations have been steadily increasing.

      Methane (CH4)

      A hydrocarbon that is a greenhouse gas with a global warming potential most recently estimated at 23 times that of carbon dioxide (CO2). Methane is produced through anaerobic (without oxygen) decomposition of waste in landfills, animal digestion, decomposition of animal wastes, production and distribution of natural gas and petroleum, coal production, and incomplete fossil fuel combustion.

      Metric Ton

      Common international measurement for the quantity of greenhouse gas emissions. A metric ton is equal to 2,205 lbs. or 1.1 short tons.

      Montreal Protocol

      The Montreal Protocol on Substances that Deplete the Ozone Layer (i.e., a protocol developed at the Vienna Convention for the Protection of the Ozone Layer), or commonly referred to as the Montreal Protocol. The Montreal Protocol is an international treaty that is structured around phasing out the production of several groups of halogenated hydrocarbons alleged to be responsible for ozone depletion, such as chlorofluorocarbons (CFCs) and other substances that contain chlorine and bromine.

      Mount Pinatubo

      An active volcano located in the Philippine Islands that erupted in 1991. The eruption of Mount Pinatubo ejected enough particulate and sulfate aerosol matter into the upper atmosphere to block some of the incoming solar radiation from reaching Earth's atmosphere. This effectively cooled the planet from 1992 to 1994, masking the warming that had been occurring for most of the 1980s and 1990s.

      Natural Gas

      Underground deposits of gases consisting of 50 to 90 percent methane (CH4) and small amounts of heavier gaseous hydrocarbon compounds such as propane (C3H8) and butane (C4H10).

      Nitrogen Oxides (NOx)

      Gases consisting of one molecule of nitrogen and varying numbers of oxygen molecules. Nitrogen oxides are produced in the emissions of vehicle exhausts and from power stations. In the atmosphere, nitrogen oxides can contribute to formation of smog, can impair visibility, and have health consequences.

      Nitrous Oxide (N2O)

      A powerful greenhouse gas with a global warming potential of 296 times that of carbon dioxide (CO2). Major sources of nitrous oxide include soil cultivation practices, especially the use of commercial and organic fertilizers, fossil fuel combustion, nitric acid production, and biomass burning.

      Non-Annex B Parties

      These are countries not listed in the Kyoto Treaty under Annex B.

      Non-Annex I Parties

      These are countries not listed in the UNFCCC under Annex I.

      North Atlantic Oscillation (NAO)

      The NAO is a large-scale fluctuation in atmospheric pressure between the subtropical high pressure system located near the Azores in the Atlantic Ocean and the subpolar low pressure system near Iceland and is quantified in the NAO Index. Surface pressure drives surface winds and wintertime storms from west to east across the North Atlantic, affecting climate from New England to western Europe as far eastward as central Siberia and the eastern Mediterranean and southward to West Africa.


      To chemically transform a substance by combining it with oxygen.

      Ozone (O3)

      Ozone, the triatomic form of oxygen (O3), is a gaseous atmospheric constituent. In the troposphere, it is created both naturally and by photochemical reactions involving gases resulting from human activities (photochemical smog). In high concentrations, tropospheric ozone can be harmful to a wide range of living organisms. Tropospheric ozone acts as a greenhouse gas. In the stratosphere, ozone is created by the interaction between solar ultraviolet radiation and molecular oxygen (02). Stratospheric ozone plays a decisive role in the stratospheric radiative balance. Depletion of stratospheric ozone, due to chemical reactions that may be enhanced by climate change, results in an increased ground-level flux of ultraviolet (UV-) B radiation.

      Ozone-Depleting Substance (ODS)

      A family of manmade compounds including chlorofluorocarbons, bromofluorocarbons (halons), methyl chloroform, carbon tetrachloride, methyl bromide, and hydrochlorofluorocarbons (HCFCs). These compounds, typically referred to as ODSs, have been shown to deplete stratospheric ozone.

      Ozone Layer

      The layer of ozone that begins approximately 9 mi. (15 km) above Earth and thins to an almost negligible amount at about 31 mi. (50 km), shielding the Earth from harmful ultraviolet radiation from the sun.

      Ozone Precursors

      Chemical compounds such as carbon monoxide, methane, nonmethane hydrocarbons, and nitrogen oxides, which in the presence of solar radiation react with other chemical compounds to form ozone, mainly in the troposphere.

      Particulate Matter (PM)

      Very small pieces of solid or liquid matter such as particles of soot, dust, fumes, mists, or aerosols. The physical characteristics of particles, and how they combine with other particles, are part of the feedback mechanisms of the atmosphere.

      Parts per billion (ppb)

      Number of parts of a chemical found in one billion parts of a gas, liquid, or solid mixture.

      Parts per million (ppm)

      Number of parts of a chemical found in 1 million parts of a particular gas, liquid, or solid.

      Perfluorocarbons (PFCs)

      A group of human-made chemicals composed of carbon and fluorine only. These chemicals were introduced as alternatives, along with hydrofluorocarbons, to the ozone-depleting substances.


      The process by which plants take in CO2 from the atmosphere (or bicarbonate in water) to build carbohydrates, releasing O2 in the process. There are several pathways of photosynthesis, with different responses to atmospheric CO2 concentrations.


      The comparatively slow torquing of the orbital planes of all satellites with respect to the Earth's axis, due to the bulge of the Earth at the equator, which distorts the Earth's gravitational field.


      Energy transfer in the form of electromagnetic waves or particles that release energy when absorbed by an object.

      Radiative Forcing

      Radiative forcing is the change in the net vertical irradiance (expressed in Watts per square meter: Wm2) at the tropopause due to an internal change or a change in the external forcing of the climate system, such as a change in the concentration of carbon dioxide or the output of the sun. Usually radiative forcing is computed after allowing for stratospheric temperatures to readjust to radiative equilibrium, but with all tropospheric properties fixed at their unperturbed values.


      Collecting and reprocessing a resource so it can be used again, for example, collecting aluminum cans, melting them down, and using the aluminum to make new cans or other aluminum products.


      Reforestation is the natural and/or artificial restocking and regeneration of trees in recently depleted forests and woodlands as a result of natural or man-made activities, such as fires, storms, flooding, landslides, insect infestations, volcanic eruptions, slash-and-burn clearing, logging, or clear-cutting.

      Residence Time

      The average time spent in a reservoir by an individual atom or molecule. With respect to greenhouse gases, residence time usually refers to how long a particular molecule remains in the atmosphere.


      The biological process whereby living organisms convert organic matter to CO2, releasing energy and consuming O2.

      Short Ton

      Measurement for a ton in the United States. A short ton is equal to 2,000 lbs. or 0.907 metric ton.


      Any process, activity, or mechanism that removes a greenhouse gas, aerosol, or precursor of a greenhouse gas or aerosol from the atmosphere.

      Soil Carbon

      A major component of the terrestrial biosphere pool in the carbon cycle. The amount of carbon in the soil is a function of the historical vegetative cover and productivity, which in turn is dependent in part upon climatic variables.

      Solar Radiation

      Radiation emitted by the sun. It is also referred to as short-wave radiation. Solar radiation has a distinctive range of wavelengths (spectrum) determined by the temperature of the sun.

      Storm Surge

      An abnormal rise in sea level accompanying a hurricane or other intense storm, the height of which is the difference between the observed level of the sea surface and the level that would have occurred in the absence of the cyclone. Storm surge is usually estimated by subtracting the normal or astronomic tide from the observed storm tide.


      Region of the atmosphere between the troposphere and mesosphere, having a lower boundary of approximately 5 mi. (8 km) at the poles to 9 mi. (15 km) at the equator and an upper boundary of approximately 31 mi. (50 km). Depending upon latitude and season, the temperature in the lower stratosphere can increase, be isothermal, or even decrease with altitude, but the temperature in the upper stratosphere generally increases with height due to absorption of solar radiation by ozone.


      The volume of water that moves over a designated point over a fixed period of time. It is often expressed as cubic feet per second (ft.3/sec).

      Sulfate Aerosols

      Particulate matter that consists of compounds of sulfur formed by the interaction of sulfur dioxide and sulfur trioxide with other compounds in the atmosphere. Sulfate aerosols are injected into the atmosphere from the combustion of fossil fuels and the eruption of volcanoes.

      Sulfur Hexafluoride (SF6)

      A colorless gas, soluble in alcohol and ether, slightly soluble in water. A very powerful greenhouse gas used primarily in electrical transmission and distribution systems and as a dielectric in electronics.

      Thermohaline Circulation (THC)

      Large-scale, density-driven circulation in the ocean, caused by differences in temperature and salinity. In the North Atlantic, the thermohaline circulation consists of warm surface water flowing northward and cold deep water flowing southward, resulting in a net poleward transport of heat.

      Trace Gas

      Any one of the less common gases found in the Earth's atmosphere. Nitrogen, oxygen, and argon make up more than 99 percent of the Earth's atmosphere. Other gases, such as carbon dioxide, water vapor, methane, oxides of nitrogen, ozone, and ammonia are considered trace gases.


      The tropopause is located between the troposphere and the stratosphere.


      The lowest part of the Earth's atmosphere from the surface to about 6 mi. (10 km) in altitude in mid-latitudes (ranging from 5.5 mi. [9 km] in high latitudes to 10 mi. [16 km] in the tropics on average) where clouds and weather phenomena occur.

      Ultraviolet Radiation (UV)

      The energy range just beyond the violet end of the visible spectrum. Although ultraviolet radiation constitutes only about 5 percent of the total energy emitted from the sun, it is the major energy source for the stratosphere and mesosphere, playing a dominant role in both energy balance and chemical composition.

      United Nations Framework Convention on Climate Change (UNFCCC)

      The Convention on Climate Change sets an overall framework for intergovernmental efforts to tackle the challenge posed by climate change. It recognizes that the climate system is a shared resource, and its stability can be affected by industrial and other emissions of carbon dioxide and other greenhouse gases.


      Water that has been used and contains dissolved or suspended waste materials.

      Water Vapor

      The most abundant greenhouse gas, it is the water present in the atmosphere in gaseous form. Water vapor is a part of the natural greenhouse effect.


      Atmospheric condition at any given time or place. It is measured in terms of such things as wind, temperature, humidity, atmospheric pressure, cloudiness, and precipitation.

      Sources: U.S. Environmental Protection Agency, U.S. Forest Service, Northwest Power and Conservation Council, U.S. Geological Survey, and National Oceanic and Atmospheric Administration.

      Compiled by AndrewHundIndependent Scholar

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      ACCESS: Africa Centre for Climate and Earth Systems Science http://africaclimatescience.org

      Amity Institute of Global Warming and Ecological Studies http://www.amity.edu/aigwes

      Asia-Pacific Network for Global Change Research http://www.apn-gcr.org/newAPN/indexe.htm

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      Center for International Climate and Environmental Research (CICERO) http://www.cicero.uio.no/home/index_e.aspx

      Climate Action Network http://www.climatenetwork.org

      Climate Analysis Indicators Tool (CAIT) http://cait.wri.org

      Climate Ark http://www.climateark.org

      Climate Change at the National Academies http://dels-old.nas.edu/climatechange

      Climate Change http://Education.Org (Global Warming Education Climate Change Science Education) http://www.climatechangeeducation.org

      Climate Change Policy—The Europe Center http://europe.stanford.edu/research/climate

      Climate Justice Initiative http://www.corpwatch.org/section.php?id=100

      Climate Institute http://www.climate.org

      Climate Science Forum http://climate-science.org

      Environmental Change Network http://www.ecn.ac.uk

      Environmental Protection Agency (EPA) Global Warming Page http://www.epa.gov/climatechange/index.html

      Green Teacher http://www.greenteacher.com

      ICLEI Europe—Climate Change Adaptation http://www.iclei-europe.org/topics/climate-change-adaptation

      Intergovernmental Panel on Climate Change http://www.ipcc.ch

      M.I.T. Joint Program on the Science and Policy of Global Change http://globalchange.mit.edu

      National Aeronautics and Space Administration (NASA) Climate Change Solutions http://climate.nasa.gov/solutions

      National Aeronautics and Space Administration Global Change Data Center (GCDC) http://science.gsfc.nasa.gov/sed/index.cfm?fuseAction=home.main&&navOrgCode=610.2)

      Natural Environment Research Council (NERC) http://www.nerc.ac.uk

      PBS NOVA/Frontline: What's Up with the Weather? http://www.pbs.org/wgbh/warming/index.html

      South East European Virtual Climate Change Center (SEEVCCC) http://www.seevccc.rs/?p=668

      True North: Adapting Infrastructure to Climate Change in Northern Canada http://nrtee-trnee.ca/climate/true-north

      Union of Concerned Scientists: Global Warming http://www.ucsusa.org/global_warming

      U.S. Forest Service—Climate Change Resource Center (CCRC) http://www.fs.fed.us/ccrc

      U.S. Global Change Research Program http://www.globalchange.gov

      Pew Center on Global Climate Change http://www.pewclimate.org

      Woods Hole Research Center: Global Warming http://www.whrc.org

      Compiled by AndrewHundIndependent Scholar


      Global Temperatures 1534

      Recent Sea-Level Rise 1535

      Achieved Hurricane Intensity Under Idealized Conditions 1536

      Annual Carbon Emissions by Region 1537

      Ice Age Temperature Changes 1538

      Sixty-Five Million Years of Climate Change 1539

      Five Million Years of Climate Change From Sediment Cores 1540

      Reconstructed Temperature, 2,000 Years 1541

      Holocene Temperature Variations 1542

      Phanerozoic Climate Change 1543

      Global Fossil Carbon Emissions 1544

      Global Warming Predictions 1545

      Global Warming Projections 1546

      Economic Efficiency of Fossil Fuel Usage 1547

      Fossil Fuel Usage per Person 1548

      Global Trends in Greenhouse Gases 1549

      Milankovitch Cycles 1550

      Graphic Plots and Text Prepared by Robert A. Rohde

      This image shows the instrumental record of global average temperatures as compiled by the Climatic Research Unit of the University of East Anglia and the Hadley Centre of the UK Meteorological Office. Data set HadCRUT3 was used, which follows the methodology outlined by Brohan et al. (2006). Following the common practice of the Intergovernmental Panel on Climate Change (IPCC), the zero on this figure is the mean temperature from 1961 to 1990.

      The uncertainty in the analysis techniques leading to these measurements is discussed in Foland et al. (2001) and Brohan et al. (2006). They estimate that global averages since ∼1950 are within ∼0.05 degree C of their reported value with 95 percent confidence. In the recent period, these uncertainties are driven primarily by considering the potential impact of regions where no temperature record is available. For averages prior to ∼1890, the uncertainty reaches ∼0.15 degree C, driven primarily by limited sampling and the effects of changes in sea surface measurement techniques. Uncertainties between 1880 and 1890 are intermediate between these values.

      Incorporating these uncertainties, Foland et al. (2001) estimated the global temperature change from 1901 to 2000 as 0.57 ± 0.17 degree C, which contributed to the 0.6 ± 0.2 degree C estimate reported by the Intergovernmental Panel on Climate Change (IPCC 2001a, [1]). Both estimates are 95 percent confidence intervals.

      This figure shows the change in annually averaged sea level at 23 geologically stable tide gauge sites with long-term records as selected by Douglas (1997). The thick, dark line is a three-year moving average of the instrumental records. These data indicate a sea-level rise of ∼18.5 cm from 1900 to 2000. Because of the limited geographic coverage of these records, it is not obvious whether the apparent decadal fluctuations represent true variations in global sea level, or merely variations across regions that are not resolved.

      For comparison, the recent annually averaged satellite altimetry data from TOPEX/Poseidon are shown in the thick gray line. These data indicate a somewhat higher rate of increase than tide gauge data, however the source of this discrepancy is not obvious. It may represent systematic error in the satellite record and/ or incomplete geographic sampling in the tide gauge record. The month-to-month scatter on the satellite measurements is roughly the thickness of the plotted gray curve.

      Much of recent sea-level rise has been attributed to global warming.

      This figure, which reproduces one of the key conclusions of Knutson and Tuleya (2004), shows a prediction for how hurricanes and other tropical cyclones may intensify as a result of global warming. Specifically, Knutson and Tuleya performed an experiment using climate models to estimate the strength achieved by cyclones allowed to intensify over either a modern summer ocean or over an ocean warmed by carbon dioxide concentrations 220 percent higher than the present day. A number of different climate models were considered, as well as conditions over all the major cyclone-forming ocean basins. Depending on site and model, the ocean warming involved ranged from 0.8 to 2.4 degrees C. Results, which were found to be robust across different models, showed that storms intensified by about one-half category (on the Saffir-Simpson Hurricane Scale) as a result of the warmer oceans. This is accomplished with a ∼6 percent increase in wind speed or equivalently a ∼20 percent increase in energy (for a storm of fixed size). Most significantly, these results suggest that global warming may lead to a gradual increase in the probability of highly destructive Category 5 hurricanes. This work does not provide any information about future frequency of tropical storms. Also, since it considers only the development of storms under nearly ideal conditions for promoting their formation, this work is primarily a prediction for how the maximum achievable storm intensity will change. Hence, this does not directly bear on the growth or development of storms under otherwise weak or marginal conditions for storm development (such as high upper-level wind shear). However, it is plausible that warmer oceans will somewhat extend the regions and seasons under which hurricanes may develop.

      This figure shows the annual fossil fuel carbon dioxide emissions, in million metric tons of carbon, for a variety of non-overlapping regions covering the Earth. Data source: Carbon Dioxide Information Analysis Center.

      Regions are sorted from largest emitter (as of 2000) to the smallest:

      United States and Canada

      Western Europe (plus Germany)

      Communist East Asia (China, North Korea, Mongolia, etc.)

      Eastern Europe, Russia, and Former Soviet States

      India and Southeast Asia (plus South Korea)

      Australia, Japan, and other Pacific Island States

      Central and South America (includes Mexico and the Caribbean)

      Middle East


      Editor's Note: According to Reuters news agency, China acknowledged in November 2010 that it was the world's largest emitter of greenhouse gases, surpassing the United States, the world's top emitter for the 20th century.

      This figure shows the Antarctic temperature changes during the last several glacial/interglacial cycles of the present ice age and a comparison to changes in global ice volume. The present day is on the right.

      The first two curves show local changes in temperature at two sites in Antarctica as derived from deuterium isotopic measurements (δD) on ice cores (EPICA Community Members 2004, Petit et al. 1999). The final plot shows a reconstruction of global ice volume based on δ180 measurements on benthic foraminifera from a composite of globally distributed sediment cores and is scaled to match the scale of fluctuations in Antarctic temperature (Lisiecki and Raymo 2005). Note that changes in global ice volume and changes in Antarctic temperature are highly correlated, so one is a good estimate of the other, but differences in the sediment record do not necessarily reflect differences in paleotemperature. Horizontal lines indicate modern temperatures and ice volume. Differences in the alignment of various features reflect dating uncertainty and do not indicate different timing at different sites.

      The Antarctic temperature records indicate that the present interglacial is relatively cool compared to previous interglacials, at least at these sites. It is believed that the interglacials themselves are triggered by changes in Earth's orbit known as Milankovitch cycles, and that the variations in individual interglacials can be partially explained by differences within this process. For example, Overpeck et al. (2006) argues that the previous interglacial was warmer because of increased solar radiation at high latitudes. The Liesecki and Raymo (2005) sediment reconstruction does not indicate significant differences between modern ice volume and previous interglacials, though some other studies do report slightly lower ice volumes/higher sea levels during the 120 ka and 400 ka interglacials (Karner et al. 2001, Hearty and Kaufman 2000). Temperature changes at the typical equatorial site are believed to have been significantly less than the changes observed at high latitude.

      This figure shows climate change over the last 65 million years. The data is based on a compilation of oxygen isotope measurements (δ180) on benthic foraminifera by Zachos et al. (2001), which reflect a combination of local temperature changes in their environment and changes in the isotopic composition of seawater associated with the growth and retreat of continental ice sheets.

      Because it is related to both factors, it is not possible to uniquely tie these measurements to temperature without additional constraints. For the most recent data, an approximate relationship to temperature can be made by observing that the oxygen isotope measurements of Lisiecki and Raymo (2005) are tightly correlated to temperature changes at Vostok, Antarctica, as established by Petit et al. (1999). Present day is indicated as 0. For the oldest part of the record, when temperatures were much warmer than today, it is possible to estimate temperature changes in the polar oceans (where these measurements were made) based on the observation that no significant ice sheets existed and hence all fluctuation (in δ180) must result from local temperature changes (as reported by Zachos et al.).

      The intermediate portion of the record is dominated by large fluctuations in the mass of the Antarctic ice sheet, which first nucleates approximately 34 million years ago, then partially dissipates around 25 million years ago, before re-expanding toward its present state 13 million years ago. These fluctuations make it impossible to constrain temperature changes without additional controls. Significant growth of ice sheets did not begin in Greenland and North America until approximately 3 million years ago, following the formation of the Isthmus of Panama by continental drift. This ushered in an era of rapidly cycling glacials and interglacials (upper right). Also appearing on this graph are the Eocene Climatic Optimum, an extended period of very warm temperatures, and the Paleocene-Eocene Thermal Maximum (labeled PETM). Due to the coarse sampling and averaging involved in this record, it is likely that the full magnitude of the PETM is underestimated by a factor of 2 to 4 times its apparent height.

      This figure shows the climate record of Lisiecki and Raymo (2005) constructed by combining measurements from 57 globally distributed deep-sea sediment cores. The measured quantity is oxygen isotope fractionation in benthic foraminifera, which serves as a proxy for the total global mass of glacial ice sheets.

      Lisiecki and Raymo constructed this record by first applying a computer-aided process of adjusting individual “wiggles” in each sediment core to have the same alignment (i.e., wiggle matching). Then the resulting stacked record is orbitally tuned by adjusting the positions of peaks and valleys to fall at times consistent with an orbitally driven ice model (see Milankovitch Cycles). Both sets of these adjustments are constrained to be within known uncertainties on sedimentation rates and consistent with independently dated tie points (if any). Constructions of this kind are common, however, they presume that ice sheets are orbitally driven, and hence data such as this cannot be used in establishing the existence of such a relationship.

      The observed isotope variations are very similar in shape to the temperature variations recorded at Vostok, Antarctica, during the 420 kyr for which that record exists. Hence, the right-hand scale of the figure was established by fitting the reported temperature variations at Vostok (Petit et al. 1999) to the observed isotope variations. As a result, this temperature scale should be regarded as approximate and its magnitude is only representative of Vostok changes. In particular, temperature changes at polar sites, such as Vostok, frequently exceed the changes observed in the tropics or in the global average. A horizontal line at 0 degrees C indicates modern temperatures (ca. 1950).

      Labels are added to indicate regions where 100 kyr and 41 kyr cyclicity is observed. These periodicities match periodic changes in Earth's orbital eccentricity and obliquity, respectively, and have been previously established by other studies (not relying on orbital tuning).

      This image is a comparison of 10 different published reconstructions of mean temperature changes during the last 2,000 years. More recent reconstructions are plotted toward the front and in redder colors, older reconstructions appear toward the back and in bluer colors. An instrumental history of temperature is also shown in black. The medieval warm period and Little Ice Age are labeled at roughly the times when they are historically believed to occur, though it is still disputed whether these were truly global, or only regional events. The single, unsmoothed annual value for 2004 is also shown for comparison.

      It is unknown which, if any, of these reconstructions is an accurate representation of climate history; however, these curves are a fair representation of the range of results appearing in the published scientific literature. Hence, it is likely that such reconstructions, accurate or not, will play a significant role in the ongoing discussions of global climate change and global warming.

      For each reconstruction, the raw data has been decadally smoothed with a δ = 5 yr. Gaussian weighted moving average. Also, each reconstruction was adjusted so that its mean matched the mean of the instrumental record during the period of overlap.

      The main figure shows eight records of local temperature variability on multi-centennial scales throughout the course of the Holocene, and an average of these (thick dark line). The records are plotted with respect to the mid-20th-century average temperatures, and the global average temperature in 2004 is indicated. The inset plot compares the most recent two millennia of the average to other high-resolution reconstructions of this period. At the far left of the main plot, the climate emerges from the last glacial period of the current ice age into the relative stability of the current interglacial. There is general scientific agreement that during the Holocene, temperatures have been quite stable compared to the fluctuations during the preceding glacial period. The average curve above supports this belief. However, there is a slightly warmer period in the middle, which might be identified with the proposed Holocene climatic optimum. The magnitude and nature of this warm event is disputed, and it may have been largely limited to summer months and/or high northern latitudes.

      Because of the limitations of data sampling, each curve in the main plot was smoothed, and consequently, this figure cannot resolve temperature fluctuations faster than approximately 300 years. Further, while 2004 appears warmer than any other time in the long-term average, an observation that might be a sign of global warming, the 2004 measurement is from a single year. It is impossible to know whether similarly large short-term temperature fluctuations may have occurred at other times, but are unresolved by the resolution available in this figure. The next 150 years will determine whether the long-term average centered on the present appears anomalous with respect to this plot. Since there is no scientific consensus on how to reconstruct global temperature variations during the Holocene, the average shown here should be understood as only a rough, quasi-global approximation to the temperature history of the Holocene. In particular, higher resolution data and better spatial coverage could significantly alter the apparent long-term behavior.

      This figure shows the long-term evolution of oxygen isotope ratios during the Phanerozoic eon as measured in fossils, reported by Veizer et al. (1999), and updated online in 2004 [1]. Such ratios reflect both the local temperature at the site of deposition and global changes associated with the extent of continental glaciation. As such, relative changes in oxygen isotope ratios can be interpreted as rough changes in climate. Quantitative conversion between this data and direct temperature changes is a complicated process subject to many systematic uncertainties; however, it is estimated that each 1 part 1,000 change in δ180 represents roughly a 1.5–2 degrees C change in tropical sea surface temperatures (Veizer et al. 2000). Also shown on this figure are blue bars showing periods when geological criteria (Frakes et al. 1992) indicate cold temperatures and glaciation as reported by Veizer et al. (2000). All data presented here have been adjusted to the 2004 ICS geologic timescale. The “short-term average” was constructed by applying a δ = 3 Myr Gaussian weighted moving average to the original 16,692 reported measurements. The gray bar is the associated 95 percent statistical uncertainty in the moving average. The “low frequency mode” is determined by applying a bandpass filter to the short-term averages in order to select fluctuations on timescales of 60 Myr or greater.

      On geologic timescales, the largest shift in oxygen isotope ratios is due to the slow radiogenic evolution of the mantle. It is not possible to draw any conclusion about very long-term (>200 Myr) changes in temperatures from this data alone. However, it is usually believed that temperatures during the present cold period and during the Cretaceous thermal maximum are not greatly different from cold and hot periods during most of the rest the Phanerozoic. Some recent work has disputed this (Royer et al. 2004), suggesting instead that the highs and lows in the early part of the Phanerozoic were both significantly warmer than their recent counterparts. Common symbols for geologic periods are plotted at the top and bottom of the figure for reference.

      Global annual fossil fuel carbon dioxide emissions, in million metric tons of carbon, as reported by the Carbon Dioxide Information Analysis Center.

      Original data: [full text] Marland, G., T. A. Boden, and R. J. Andres (2003). “Global, Regional, and National CO2 Emissions” in Trends: A Compendium of Data on Global Change. Oak Ridge, Tenn., U.S.A.: Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy.

      The data are originally presented in terms of solid (e.g., coal), liquid (e.g., petroleum), gas (i.e., natural gas) fuels, and separate terms for cement production and gas flaring (i.e., natural gas lost during oil and gas mining). In the plotted figure, gas flaring (the smallest of all categories) was added to the total for natural gas. Note that the carbon dioxide releases from cement production result from the thermal decomposition of limestone into lime, and so technically are not a fossil fuel source.

      This figure shows the predicted distribution of temperature change due to global warming from the Hadley Centre HadCM3 climate model. These changes are based on the IS92a (“business as usual”) projections of carbon dioxide and other greenhouse gas emissions during the next century, and assume normal levels of economic growth and that no significant steps are taken to combat global greenhouse gas emissions.

      The plotted gray tints show predicted surface temperature changes expressed as the average prediction for 2070–2100 relative to the model's baseline temperatures in 1960–90. The average change is 3.0 degrees C, placing this model on the lower half of the Intergovernmental Panel on Climate Change's 1.4–5.8 degrees C predicted climate change from 1990 to 2100. As can be expected from their lower specific heat, continents are expected to warm more rapidly than oceans, with an average of 4.2 degrees C and 2.5 degrees C in this model, respectively. The lowest predicted warming is 0.55 degree C south of South America and the highest is 9.2 degrees C in the Arctic Ocean (points exceeding 8 degrees C are plotted as black).

      This model is fairly homogeneous, except for strong warming around the Arctic Ocean related to melting sea ice and strong warming in South America related to predicted changes in the El Niño cycle and Brazillian rainforest. This pattern is not a universal feature of models, as other models can produce large variations in other regions (e.g., Africa and India) and less extreme changes in places like South America.

      This figure shows climate model predictions for global warming under the SRES A2 emissions scenario relative to global average temperatures in 2000. The A2 scenario is characterized by a politically and socially diverse world that exhibits sustained economic growth, but does not address the inequities between rich and poor nations, and takes no special actions to combat global warming or environmental change issues. This world in 2100 is characterized by large population (15 billion), high total energy use, and moderate levels of fossil fuel dependency (mostly coal). At the time of the IPCC Third Assessment Report, the A2 scenario was the most well-studied of the SRES scenarios.

      The IPCC predicts global temperature change of 1.4–5.8 degrees C due to global warming from 1990 to 2100 (IPCC 2001a). As evidenced above (a range of 2.5 degrees C in 2100), much of this uncertainty results from disagreement among climate models, though additional uncertainty comes from different emissions scenarios.

      This figure shows an estimate of how efficiently the world's 20 largest economies convert fossil fuel usage into wealth as expressed by the ratio of their gross domestic product (or GDP, calculated by the method of purchasing power parity in U.S. dollars) over the number of kilograms of fossil fuel carbon released into the atmosphere each year. The relatively narrow range of variation between most countries in this figure suggests that the pursuit of wealth in the present world is strongly tied to the availability of fossil fuel energy sources.

      As countries may be reluctant to combat fossil fuel emissions in ways that cause economic decline, this figure serves to suggest the degree to which different large economies can decrease emissions through short-term improvements in efficiency and alternative fuel programs.

      The two countries that produce the highest GDP per kilogram carbon, Brazil and France, are heavily reliant on alternative energy sources, hydroelectric and nuclear power, respectively.

      This figure shows the disparity in fossil fuel consumption per capita for the countries with the 20 largest populations. The large range of variation is indicative of the separation between the rich, industrialized nations and the poor/developing nations. The global average is also shown.

      As most countries desire wealth and aim to develop that wealth through the development of industry, this figure suggests the degree to which poor nations may strive to increase their emissions in the course of trying to match the industrial capacity of the developed world. Managing such increases and dealing with the apparent social inequality of the present system will be one of the challenges involved in confronting global warming.

      Global trends in major greenhouse gas concentrations. The rise of greenhouse gases, and their resulting impact on the greenhouse effect, are believed to be responsible for most of the increase in global average temperatures during the last 50 years. This change, known as global warming, has provoked calls to limit the emissions of these greenhouse gases (e.g., the Kyoto Protocol). Notably, the chlorofluorocarbons CFC-11 and CFC-12 shown above have undergone substantial improvement since the Montreal Protocol severely limited their release due to the damage they were causing to the ozone layer.

      At present, approximately 99 percent of the 100-year global warming potential for all new emissions can be ascribed to just three gases: carbon dioxide, methane, and nitrous oxide.

      Milankovitch Cycles

      The Earth's orbit around the sun is slightly elliptical. Over time, the gravitational pull of the moon and other planets causes the Earth's orbit to change following a predictable pattern of natural rhythms, known as Milankovitch cycles. Over a ∼00,000-year cycle, the Earth migrates from an orbit with near-zero eccentricity (a perfect circle) to one with approximately 6 percent eccentricity (a slight ellipse). In addition, the tilt of the Earth axis, known as its obliquity, varies from 21.5 to 24.5 degrees, with a 41,000-year rhythm. And last, the orientation of the Earth's axis rotates with a ∼20,000-year cycle relative to the orientation of the Earth's orbit. This cycle, known as “precession,” affects the intensity of the seasons.

      The figure shows the pattern of changes in each of the three modes of orbital variability: eccentricity, obliquity, and precession. These changes in the Earth's orbit lead to a complex series of changes in the amount of sunlight that a given location on Earth can expect to receive during a given season. An example is shown for summer sunlight near the Arctic circle. Sunlight at this location is believed to influence the growth and decay of ice sheets during ice ages. The last line shows measured changes in climate during the last million years, with warm interglacials highlighted in gray bands. As can be seen, such interglacials appear to preferentially occur near maxima in eccentricity and slightly following times of maximum summer sunlight.

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      VOLUME 1: Library of Congress: 232, 381; National Aeronautics and Space Administration: 49, 116, 125, 152, 168, 279, 284, 397, 418, 542; National Oceanic and Atmospheric Administration: 21, 80, 236, 335; National Science Foundation: 56; http://Photos.com: 2,5,13,17,40, 35, 71, 85, 90, 101, 130, 134, 148, 177, 180, 186, 195, 209, 212, 221, 240, 245, 250, 264, 269, 272, 304, 310, 314, 318, 340, 346, 348, 355, 372, 406, 411,423, 427, 441, 456, 459, 462, 469, 501, 521, 526; Sandia National Laboratories: 510; United Nations Educational, Scientific and Cultural Organization: 470; U.S. Archives and Records: 391; USAID: 202, 259, 434, 448; U.S. Coast Guard: 324; U.S. Department of Agriculture Agricultural Research Service: 18, 141, 477; U.S. Department of Energy: 293, 391; U.S. Embassy: 161; U.S. Environmental Protection Agency: 62, 491; U.S. Fish and Wildlife Service: 408; U.S. Geological Survey: 26; U.S. Navy: 535; Wikimedia Commons: 108 (left and right), 364, 482.

      VOLUME 2: Argonne National Laboratory: 859; Federal Emergency Management Agency: 798; Lawrence Liver-more National Laboratory: 1036; Morguefile: 929; National Aeronautics and Space Administration: 594 (left and right), 704, 725, 735, 869, 976; National Oceanic and Atmospheric Administration: 563, 969, 983; National Science Foundation: 668, 946; http://Photos.com: 553, 556, 568, 575, 580, 587, 606, 625, 632, 650, 657, 685, 695, 713, 716, 742, 760, 787, 805, 812, 819, 822, 831, 843, 876, 885, 900, 908, 920, 936, 952, 1009, 1012, 1051, 1060, 1073; http://StockExhng.com: 999; Taylor Shellfish Farms: 1044; USAID/Kendra Helmer: 1020; U.S. Department of Agriculture Agricultural Research Service: 849, 960; U.S. Department of Defense: 728, 767, 913; U.S. Department of Energy: 643; U.S. Department of Housing and Urban Development: 792; U.S. Department of the Interior: 891; U.S. Fish and Wildlife Service: 1068; U.S. Geological Survey: 616, 779, 941; U.S. Navy: 992; White House: 662; Wikimedia Commons: 864, 1078.

      VOLUME 3: Celestia Motherlode/Neethis; 1263; Climate Prediction Center: 1281; Federal Emergency Management Agency: 1447; Getty Images: 1464; Andy Green: 1378, 1482, 1489; International Institute for Sustainable Development: 1238; Morguefile: 1477; National Aeronautics and Space Administration: 1147, 1163, 1204, 1235, 1269, 1299, 1304, 1307, 1352, 1418, 1426, 1459; National Aeronautics and Space Administration/Boeing: 1181; National Oceanic and Atmospheric Administration: 1157, 1167, 1205, 1215, 1232, 1243, 1297, 1310, 1409, 1471, 1511; National Park Service: 1357; National Science Foundation: 1121; Nellis Air Force Base: 1193; Oxfam East Africa: 1027; http://Photos.com: 1084, 1087, 1094, 1114, 1126, 1157, 1253, 1286, 1324, 1333, 1336, 1341, 1349, 1375, 1431, 1437, 1440, 1454, 1498; Pieternella Pieterse/Concern Worldwide/USAID: 1260; Sebastian Schulze: 1196; http://StockExhng.com: 1214, 1224, 1248, 1274, 1321; United Nations/Evan Schneider: 1387; U.S. Department of Agriculture Agricultural Research Service: 1107; U.S. Department of Energy: 1188; U.S. Geological Survey: 1142; U.S. House of Representatives: 1392; U.S. Navy: 1362; White House: 1174; Wikimedia Commons: 1098, 1139, 770, 1314, 1370, 1406; Wikimedia Commons:/John Southern: 1344; Wikimedia Commons:/Yoo Chul Chung: 836; J. Young, Natural History Museum, London/U.S. Department of Energy: 1403.

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