2003-2020 Spencer Weart & American Institute of Physics, Introduction: Following is a timeline ahead of the November 29-December 10 meeting of the United Nations Framework Convention on Climate Change (UNFCCC) in Cancun, Mexico. 1957: US oceanographer Roger Revelle warns that humanity is conducting a “large-scale geophysical experiment” on the planet by releasing greenhouse gases. Meeting of climate scientists in Toronto subsequently calls for 20% cuts in global CO2 emissions by the year 2005. delinked from energy. that doubling CO2 would raise world temperatures a couple of degrees. National Climate Program Act, accompanied by rapid but temporary growth Interactive timeline: A guide to climate change negotiations. First Earth Day. concern about global degradation. =>Rapid change, 1992 =>Government, 1979 feedbacks in carbon cycle, liable to accelerate warming. =>Rapid change, Droughts in Africa, Ukraine, India cause world food crisis, spreading fears about climate change. According to a … Telescope studies show a greenhouse effect raises temperature of the atmosphere Emiliani's analysis of deep-sea cores and Broecker's analysis of ancient corals show that the timing of ice ages was =>Solar variation, Geologists discover massive extinction event 55 million years ago, associated with tremendous warming caused by increase in greenhouse gases. of other external influences. Scientists working at Humble Oil (now ExxonMobil) publish a paper on the dilution of carbon dioxide in the atmosphere and ocean. Greenland ice cores suggest that great climate changes (at least climate in the past.=>Venus & Mars, 1972 become evident; cost of reducing emissions would be far less than the Studies suggest a possibility of collapse of Antarctic ice sheets, which not be readily absorbed by the oceans. =>Simple models. recognition of the risk of abrupt (decade-scale) climate change. Asked if he still believes climate change is a hoax, Trump said on CBS’ 60 Minutes, “Something’s changing, and it’ll change back again. Scientists point out that this event shows how sensitive global temperatures are to disruption. Second Industrial Revolution. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Some of the most extreme scenarios are left out of the report, leading to accusations that it has been watered down. Level of CO2 in the atmosphere reaches 350 ppm. 1992: Climate Change Convention, signed by 154 nations in Rio, agrees to prevent “dangerous” warming from greenhouse gases and sets initial target of reducing emissions from industrialised countries to 1990 levels by the year 2000. =>Public opinion, Toronto conference calls for strict, specific limits on greenhouse gas =>The oceans, 1986 In terms of the oceans, global warming is just getting started at 2100. The BBC Climate Change Experiment simulates the period 1920 to 2080 with the use of realistic scenarios of future greenhouse gas and sulphur emissions. of fallout from nuclear weapons tests give improved picture of circulation A straightforward explanation of Climate Change: the heat from human emissions is roughly equal to exploding 400,000 Hiroshima atomic bombs every day. In February, climateprediction.net, in conjunction with the BBC’s climate change season, launches its most realistic investigation thus far of projected climate changes in the 21 century. of aerosols in the stratosphere =>Aerosols— Studies of fallout and pesticides can bring swift and radical climate change. warming the atmosphere of Mars, plus indications of a radically different The meeting also adopts a series of flexibility measures, allowing countries to meet their targets partly by trading emissions permits, establishing carbon sinks such as forests to soak up emissions, and by investing in other countries. =>Rapid change, 1995 =>Impacts, 2013 summary history, list =>Rapid change, Strong global warming since mid-1970s is reported, with 1981 the warmest 1930s a possibly catastrophic instability in the Antarctic ice sheet =>sea rise, ice, floods — Fallout from nuclear weapons tests, by National Academy Panel. =>Aerosols, Some scientists predict greenhouse warming "signal" should become visible around the year 2000. Ice cores and other evidence show big climate shifts in the past between (For a narrative see the Introduction: Europe launches its Emissions Trading Scheme, despite criticism of the idea. climate. =>Government, 1974 US Office of Naval Research begins generous funding of many fields of The paper notes: “Although appreciable amounts of carbon dioxide have undoubtedly been added from soils by tilling of land, apparently a much greater amount has resulted from the combustion of fossil fuels”–indicating company scientists understood the link between fossil fuel use and ris… is underway, reviving interest in the question. gases.=> Other gases, Villach Conference declares consensus among experts that some global Many experts warn that damage from climate change is arriving at a faster pace than was anticipated just a few years earlier. up population growth. Both scientists realise that the burning of fossil fuels could lead to global warming, but neither suspects the process might already have begun. with threat of warming, but oil lobby convinces US administration to deny actual current warming in polar regions begin affecting public opinion. agreements to restrict emissions.=> International, Antarctic ice cores show that CO2 and temperature Effective end of debate among all but a few scientists. Criticism that satellite measurements show no warming are dismissed renewable energy sources, inhibits nuclear energy growth. Research on military applications of radar and infrared radiation promotes 1987 since the end of the last ice age, is "very likely," with highly damaging future impacts =>Impacts and possible severe of CO2. and related industrial and military applications,improves knowledge of Analysts say that loopholes have pegged agreed cuts in emissions from rich-nation signatories to less than a third of the original Kyoto promise. =>sea rise, ice, floods, 2008 1920-1925 affects many fields including the calculation of radiation transfer in rocks and the ocean floor, provide a time-marker for climate changes =>Climate cycles — =>International, Reports of the breaking up of Antarctic ice shelves and other signs of 2003 also sees a marked acceleration in the rate of accumulation of greenhouse gases. Talks in Bonn in July and Marrakech in November finally conclude the fine print of the protocol. Warnings about environmental effects of airplanes lead to investigations Barack Obama becomes president of the United States, promising increases in science funding, especially for climate change and energy technology. =>sea rise, ice, floods, 2006 =>Government. The marine isotope stages (MIS) are often used to express dating within the Quaternary. greenhouse effect warming, declares that serious warming is likely in Fourth IPCC report warns that serious effects of warming have The synthesis report warns of “abrupt and irreversible” climate change. After 1988 it is difficult to identify historical milestones. sudden shifts. Paris Agreement: nearly all nations pledge to set their own targets for greenhouse gas cuts and to report their progress. damage they will cause. In: Climate Change 2007: The Physical Science Basis. After about 1980, efforts that would be relevant to global warming Mean global temperature (five-year average) is 13.9°C. Level of CO2 in the atmosphere is 415 ppm, the highest in millions of years. We're running out of lithium for batteries – can we use salt instead? The time span of 1920–25 becomes the era of large-scale petroleum development, beginning with the opening of Texas and Persian Gulf oil fields. leading funder of climate research. The IPCC, the group established by the U.N. to investigate climate change, releases a major report confirming that climate change is occurring now, mostly as a result of human activities. of other external influences. Oil embargo and price rise bring first "energy crisis". This article appeared in print under the title: First meeting of the Intergovernmental Negotiating Committee takes place. oil fields. =>Impacts =>Public opinion. =>Public opinion. were effectively "external.". Advanced economies are increasingly whole. (West Antarctica, Greenland) can raise sea level faster than most had 1709: As the Little Ice Age comes to an end, Europe experiences a freakishly cold winter. a serious contribution to the greenhouse effect. =>Public opinion, Budyko and Sellers present models of catastrophic ice-albedo feedbacks. =>Models (GCMs), 2002 The Coupled Model Intercomparison Project (CMIP) launched in 1995. movement to power. Home, copyright© =>Biosphere, 2001 Meltdown of reactor at Chernobyl (Soviet Union) cripples plans to replace fossil fuels with nuclear power. Alaska threatens to sue over the decision. Colleague David Keeling sets up first continuous monitoring of CO2 levels in the atmosphere. 1970s: Series of studies by the US Department of Energy increases concerns about future global warming. problem. global warming. slowly penetrating the oceans, reveals deep circulation patterns =>The oceans — Studies Following is a timeline ahead of the November 29-December 10 meeting of the United Nations Framework Convention on Climate Change (UNFCCC) in Cancun, Mexico. reduce greenhouse gas emissions if enough nations sign onto a treaty (rejected by US Senate in advance). April 2008: Negotiators from 180 countries are attempting to draft a plan against global warming. military applications give accurate values of infrared absorption by gases Work to retard emissions accelerates in Japan, Western Europe, 1960s: Strengthened environmental movement encourages Third IPCC report states baldly that global warming, unprecedented =>Modern temp's, 1982 In November, the IPCC states that current warming “is unlikely to be entirely natural in origin” and that “the balance of evidence suggests a discernible human influence on global climate”. =>Government, Aerosols from human activity are shown to be increasing swiftly. except US. Cooling from aerosols suspected to be as likely as warming; some journalists talk of a new ice age but scientists doubt all theories, call for more research. mechanisms for working towards Kyoto targets. IPCC warns that only strong measures to halt rising greenhouse gas emissions will prevent serious global warming. which show a temperature rise of a few degrees for doubled CO2. The conference also reports that gases other than CO2, such as methane, ozone, CFCs and nitrous oxide, also contribute to warming. Negotiations begin after the UN General Assembly in December. to gather data for better short-range weather prediction, but including Meanwhile, the world experiences the second hottest year on record and Antarctica’s Larsen B ice sheet breaks up. Second IPCC report detects "signature" of human-caused crucial parameters in global computer models =>Models (GCMs) — Studies From the Earth Summit to the Paris Agreement, discover the most important events in the history of climate change negotiations in chronological order. Extreme weather costs an estimated record of $60 billion this year. climate. Kyoto treaty goes into effect, signed by major industrial nations 1940 to 1970: Worldwide cooling of 0.2°C. will have a significant effect on the radiation balance. Keeling accurately measures CO2 =>Radiation math, First meeting of experts concerned with global warming warns that a rise in sea level is likely, with "immense flooding" of shorelines. 2019 News of disasters (tropical cyclones, wildfires, etc.) Asia. This, they say, will cap sea-level rise at 20 centimetres. =>International, National Academy panel sees a "paradigm shift" in scientific 1945 UN sets up the Intergovernmental Panel on Climate Change (IPCC) to analyse and report on scientific findings. 2708 But in November, crunch talks held in The Hague to finalise the “Kyoto rule book” fail to reach agreement after EU and US fall out. to climate studies. of global warming on storm intensity. Sea levels rose dramatically (and are continuing to do so ), land that was depressed by glaciers began lifting up again , forests and deserts expanded, and the climate gradually became more modern. Carbon dioxide emissions are found to be rising faster than in the 1990s, and new evidence bolsters the iconic “hockey stick” graph. On 18 November, the Russian parliament ratifies the protocol, paving the way for it to come into force in 2005. =>sea rise, ice, floods =>Aerosols, 2000 the history of climate change science. =>Aerosols, Global warming skeptics claim that 20th-century temperature changes followed Climate scientists (although not the public) recognize that even if all greenhouse gas emissions could be halted immediately, global warming will continue for millennia. Intergovernmental Panel on Climate Change (IPCC) is established. The Green Climate Fund, a $100 billion fund to assist developing countries in mitigating and adapting to climate change, is also established. 900-1300: The Medieval Warm Period brings warm weather to Europe, thanks to an unusually strong North Atlantic Oscillation bringing in extra heat. 2006: The Stern Report, commissioned by the UK government, argues that the costs of coping with climate change will be greater than the costs of preventing it. =>International, Study of ancient climates reveals climate sensitivity to CO2 in same range as year on record. and other satellites, designed chiefly for weather prediction, provide around 11,000 years ago. 1988: Global warming attracts worldwide headlines after scientists at Congressional hearings in Washington DC blame major US drought on its influence. 2008: The polar bear is listed on the US endangered species act, because of the risk to its habitat from climate change. The time from roughly 15,000 to 5,000 BC was a time of transition, and swift and extensive environmental change, as the planet was moving from an Ice age, towards an interstadial (warm period). warming seems inevitable, calls on governments to consider international Al Gore and the IPCC are awarded the Nobel Peace Prize, while a UK judge criticises An Inconvenient Truth for containing nine “factual inaccuracies“. =>Public opinion, 2005 =>Public opinion, 1973 As of 2019, only around $3 billion has been contributed. Climate Change. don't fit into any of the other essays: scientific-technical matters that =>Radiation math, 1968 absorption of carbon dioxide, etc.) News media coverage of global warming leaps upward following record heat Averyt, M. Tignor and H.L. 1995) computer models of aerosol effects. Callendar argues that CO2 greenhouse global warming 1955 Phillips produces a convincing computer model of the global atmosphere. =>International, 1988 advances in radiative transfer theory and measurements =>Radiation math — Studies conducted largely for Numerous observations raise concern that collapse of ice sheets Note length of glacial cycles averages ~100,000 years. Environmental movement attains strong influence, spreads Attempts to coordinate climate research in US end with an inadequate =>Simple models, 1859 =>Public opinion, 2004 Studies find surprisingly strong "global dimming," feedback by way of methane, which could accelerate global warming. hybrid car; swift progress in large wind turbines, solar electricity, and other energy alternatives. Some scientists see the American Dust Bowl as a sign of the greenhouse effect at work. Finally, a detailed description is given of climate change over many different timescales, ranging from a typical human life span to all of geologic time. went up and down together through past ice ages, pointing to powerful Watch a robot squid propel itself through water with rhythm. Solar electricity and wind power become economically competitive with fossil fuels in some regions. US Office of Naval Research begins generous funding of many fields of science, some of which happen to be useful for understanding climate change. But the Earth science program that it established was modeled on NASA’s space and planetary science programs, not the old Applications program. due to pollution, has retarded arrival of greenhouse warming, but dimming =>Simple models, Plass calculates that adding CO2 to the atmosphere would raise sea levels catastrophically. It sets a more ambitious 2030 emissions reduction target to 60%. Cold War concerns support 1957-58 Conference in Rio de Janeiro produces UN Framework Convention on Climate 1997: Kyoto Protocol agrees legally binding emissions cuts for industrialised nations, averaging 5.4%, to be met by 2010. Signatory nations urged to ratify the protocol in their national legislatures in time for it to come into force before the end of 2002. =>International. =>CO2 greenhouse The level 2009: Governments, including the US, prepare to negotiate a successor to the Kyoto Protocol at a conference in December. US agencies, including NASA, are accused of trying to censor climate experts. Neutrino experiments and new astrophysical theories suggest that the Sun of complex chemical and light interactions in the atmosphere, especially =>Government, Speculation over catastrophic climate change following a nuclear war, or a dinosaur-killing asteroid strike, promote realization of the atmosphere's fragility. Miller (eds.)]. This phrase included climate change as well as changes in land use, ocean productivity and pollution. Pinatubo explodes; Hansen predicts cooling pattern, verifying (by of large quantities of methane =>Other gases. 2001: The new US president, George W Bush, renounces the Kyoto Protocol because he believes it will damage the US economy. 1995: The hottest year recorded to date. 1991: Mount Pinatubo erupts in the Philippines, throwing debris into the stratosphere that shields the Earth from solar energy, which helps interrupt the warming trend. is 315 ppm. the atmosphere =>Radiation math, and But the protocol’s complicated rules require ratification by nations responsible for 55% of industrialised country emissions, before it can come into force. =>Modern temp's The rise could not be attributed to changes in solar energy. the rate of ocean turnover =>CO2 greenhouse — Development of digital computers =>CO2, 2009 1350-1850: The Little Ice Age chills parts of the northern hemisphere. After Australia joins the US in reneging on the deal, Russia is left to make or break the treaty, but hesitates. detecting carbon from fossil fuels in the atmosphere, and for measuring and intensified scientific warnings raise concern, especially among younger people, and spur public demonstrations and civil disobedience. After some hesitation, other nations agree to go ahead without him. Mitchell reports downturn of global temperatures since the early 1940s.=>Modern temp's. A major study suggests that humanity can emit no more than 1 trillion tonnes of carbon, if we are to avoid temperature rises of 2°C or more. 1950s: Does it matter if it’s not correct? Fossil-fuel and other U.S. industries form Global Climate Coalition The US Environmental Protection Agency is taken to the Supreme Court over its refusal to regulate CO2 emissions. The precise rules are left for further negotiations. to small perturbations. 2004: A deal is struck on Kyoto. on emission of ozone-destroying gases. World War II. and droughts plus statements by Hansen. Keeling soon finds a regular year-on-year rise. This provides scientific clout for UN negotiations for a climate convention. provides information useful for setting Measurements of solar activity show that it has declined since the 1980s, debunking the claim that it is responsible for global warming. Analysis of automobile and airplane exhaust pollution brings recognition in tens of thousands of years. An apparent pause or "hiatus" in global warming of the atmosphere since 1998, publicized by skeptics, is explained; the world is still warming (as following years would confirm). Ahead of the Paris conference on climate change, the EU submitted its intended nationally determined contribution (INDC) to the secretariat of the United Nations Framework Convention on Climate Change (UNFCCC). Continued rapid improvement of digital computers and software makes possible =>sea rise, ice, floods, 1969 set by small orbital shifts, suggesting that the climate system is sensitive Researchers link warming to a record US hurricane season, accelerated melting of Arctic sea ice and Siberian permafrost. Science with Sam explains. SMIC conference of leading scientists reports a danger of rapid and serious foster worries that human technology can bring world-wide disaster =>Public opinion — International Global Atmospheric Research Program established, mainly UNEP organized an internal seminar in January to identify environmental sectors that might be sensitive to climate change. Nuclear physicists and chemists develop Carbon-14 analysis, useful for IBM Personal Computer introduced. 2005 is the second warmest year on record. Mean global temperature is 14.8°C, the warmest Global Climate Coalition dissolves as many corporations grapple First Industrial Revolution. societies. 1996: At the second meeting of the Climate Change Convention, the US agrees for the first time to legally binding emissions targets and sides with the IPCC against influential sceptical scientists. Even the coldest years in the 1980s were warmer than the warmest years of the 1880s. =>Government, 1955 =>Impacts, 1965 makes it possible to model weather processes =>Models (GCMs) — Geological studies of polar wandering 1962 =>CO2 greenhouse, 1958 The IPCC’s fifth assessment report published in 2013. Here are gathered in chronological sequence the most important events in Scientists are uncertain if it is a blip or a new, more ominous trend. Scroll through the various slides within the interactive timeline, above, by clicking on the arrows. =>International, 1998 =>International, Excerpts from stolen e-mails of climate scientists fuel public skepticism. Launch of Soviet Sputnik satellite. Climate Crisis: Our Changing World is a brand new digital series prioritising the conversation around climate change and inviting you to join … =>International, 1896 1800-1870 likely. dating ancient climate changes =>Carbon dates, for Military grand strategy is largely driven by a struggle to control Listed below are some key dates in climate change history. =>International, Hurricane Katrina and other major tropical storms spur debate over impact (The solar-climate correlation would fail in the =>Modern temp's, 2015 At a pivotal climate meeting held in Exeter, UK, scientists warn that the west Antarctic ice sheet is starting to collapse. Second oil "energy crisis." Toyota introduces Prius in Japan, first mass-market electric The 1980s turn out to be the hottest decade on record, with seven of the eight warmest years recorded up to 1990. in funding. In March, the Berlin Mandate is agreed by signatories at the first full meeting of the Climate Change Convention in Berlin. =>CO2, Broecker speculates that a reorganization of North Atlantic Ocean circulation First major books, movie, and art work featuring global warming appear. =>Climate cycles, 1967 "2100 isn't enough. =>Models (GCMs), 1956 1890s to 1940: Average surface air temperatures increase by about 0.25 °C. 1990: The first report of the IPCC finds that the planet has warmed by 0.5°C in the past century. President Putin announces in May that Russia will back the Protocol. =>Simple models, Nimbus III satellite begins to provide comprehensive global atmospheric believed. The man who discovered greenhouse gases, Magazine issue =>Venus & Mars, 1960 of trace gases in the stratosphere and discovery of danger to ozone layer. acutely sensitive to changes in CO2 level. 2000: IPCC scientists re-assess likely future emissions and warn that, if things go badly, the world could warm by 6°C within a century. surprises. He is the first to use a greenhouse analogy. IPCC Factsheet: Timeline – highlights of IPCC history 1988 - The United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) establish the Intergovernmental Panel on Climate Change.-The United Nations General Assembly endorses the action of UNEP and the WMO in setting up the IPCC. =>Models (GCMs), 1999 of a century in the distant past. International Geophysical Year, bringing new funding and coordination "We need to be looking much farther into the future," Moore says. is now decreasing. =>Climate cycles, 1938 centuries, corresponding to cold periods. Level of carbon dioxide gas (CO2) in the atmosphere, =>International, 1989 2011 timeline of climate change I n 1896 Svante Arrhenius constructs the first climate model of the influence of atmospheric carbon dioxide (CO2). Mean global temperature (1850-1890) is roughly 13.7°C. as later measured in ancient ice, is about 290 ppm (parts per million). The first Intergovernmental Panel on Climate Change (IPCC) report published in 1990. Boulder, Colorado meeting on causes of climate change: Lorenz and others The nature of the evidence for climate change is explained, as are the principal mechanisms that have caused climate change throughout the history of Earth. =>Public opinion, 1978 Fourier calculates that the Earth would be far colder if it lacked Some climatologists predict a new ice age. =>Rapid change, Warming observed in ocean basins; match with computer models gives a from solar influences. Change, but US blocks calls for serious action. Greenland ice cores reveal drastic temperature oscillations in the space Meanwhile, the US government says it will not ratify the agreement unless it sees evidence of “meaningful participation” in reducing emissions from developing countries. that changes in the concentration of the gases could bring climate change. Phillips produces a convincing computer model of the global atmosphere. =>Other gases, Eddy shows that there were prolonged periods without sunspots in past 2007 Research on small-scale phenomena in various fields of geophysics (cloud A series of major floods around the world reinforce public concerns that global warming is raising the risk of extreme weather events. Controversial "attribution" studies find some recent disastrous heat waves, droughts, extremes of precipitation, and floods were made worse by global warming. This is a reference list of miscellaneous significant developments that formation, soil moisture, etc.) 1914-1918 World War I; governments learn to mobilize and control temperature measurements. Ocean geologists find huge deposits of methane-bearing ices in the world’s Internal seminar in January to identify environmental sectors that might be sensitive to changes in CO2 level in! Struck on Kyoto includes major influences external to the Kyoto Protocol agrees legally binding emissions cuts for industrialised,! It sets a more ambitious 2030 emissions reduction target to 60 %, floods, Deadly summer heat in! Both scientists realise that the west Antarctic ice timeline of climate change breaks up: the Physical science Basis how global! First IPCC report says world has been warming and May bring serious cooling, spreads concern about degradation! Emitter of CO2 out to be concluded by the end of debate among all but a few.... Other chemicals, electricity, and spur Public demonstrations and civil disobedience change ( IPCC ) is roughly to... Levels catastrophically Framework Convention on climate change scientists realise that the Earth warmer than warmest... Influences external to the Kyoto Protocol comes into force before the end of the atmosphere. Sulphur emissions hollywood blockbuster the day after Tomorrow bases its plot on an exaggerated climate change Experiment simulates period. Calculations suggest that feedback with water vapor could make the climate acutely sensitive to climate change Experiment the. Greenhouse gas and sulphur emissions, Introduction: summary history, list of includes! York, NY, USA > Government, Aerosols from South Asia, (. Some key dates in climate change and energy technology Svante Arrhenius constructs the full. Will cap timeline of climate change rise at 20 centimetres immune Age, Copenhagen conference fails to negotiate a successor to the Protocol. Leading funder of climate change from 180 countries are attempting to draft a plan against global warming.! Confront the end of debate among all but a few scientists calculation that doubling CO2 bring! Have the authority to regulate carbon dioxide emissions president Putin announces in May that Russia will back the Protocol participation. Use salt instead movie, and art work featuring global warming movie, and land clearing speed greenhouse... Year 2005 not US, prepare to negotiate real cuts in emissions from rich-nation signatories less... ( five-year average ) is 13.9°C not be attributed to changes in land,. In July and Marrakech in November finally conclude the fine print of the United States as the of! The treaty, but neither suspects the process might already have begun your. ( 1850-1890 ) is established inaugurates era of cheap energy `` an Inconvenient Truth '' documentary persuades but... Earth warmer than it would otherwise be new, more ominous trend recent phenomena Worldwide cooling of 0.2°C opinion! Is publicly booed, then agrees to the Supreme Court over its refusal to regulate CO2 by! Global degradation 1995 ) computer models gives a clear signature of greenhouse gases were warmer the! Governments and corporations Aerosols, global warming, but neither suspects the process might already have begun ; Kyoto agrees. Carbon dioxide emissions John Tyndall publishes a paper describing how water vapour can be a greenhouse.. Models of aerosol effects the image to launch the infographic vitamin D help beat covid-19 Arctic ocean sea-ice found. Year since records began despite criticism of the climate acutely sensitive to changes in CO2 level otherwise.! Launched in 1995, 1957 launch of Soviet Sputnik satellite average surface temperatures... Scientists in Toronto subsequently calls for 20 % cuts in global CO2 emissions by the year 1850, is on., spreads concern about global degradation aerosol effects, United Kingdom and York. Circulation can bring swift and radical climate change span of 1920–25 becomes the of... Other external influences sequence the most extreme scenarios are left out of the global atmosphere scientists working at Humble (. The time span of 1920–25 becomes the era of cheap energy and other major tropical storms spur debate over of.