Climate change in popular culture

The issue of climate change, its possible effects, and related human-environment interaction have entered popular culture since the late 20th century.

Science historian Naomi Oreskes has noted that "there's a huge disconnect between what professional scientists have studied and learned in the last 30 years, and what is out there in the popular culture". An academic study contrasts the relatively rapid acceptance of ozone depletion as reflected in popular culture with the much slower acceptance of the scientific consensus on global warming.

Literature

* Arctic Drift (2008) by Clive Cussler and Dirk Cussler. A thriller involving attempts to reverse global warming, a possible war between the US and Canada, and “a mysterious silvery mineral traced to a long-ago expedition in search of the fabled Northwest Passage.”

* Fallen Angels (1991) by Larry Niven, Jerry Pournelle, and Michael Flynn. Set in North America in the "near future", a radical technophobic green movement dramatically cuts greenhouse gas emissions, only to find that manmade global warming was staving off a new ice age.

* Forty Signs of Rain (2004), Fifty Degrees Below (2005), and Sixty Days and Counting (2007) comprise the Science in the Capital series, a hard science fiction trilogy by Kim Stanley Robinson. Set primarily in Washington, D.C., abrupt climate change causes weather disasters in the US capitol and flooding of the fictional island nation of Khembalung. Main characters are American scientists, politicians, and Buddhist monks.

* State of Fear by Michael Crichton, was released criticizing the Global warming consensus and accusing its proponents of using fear tactics.

Film

* The Day After Tomorrow (2004) starring Dennis Quaid. An abrupt shutdown of thermohaline circulation causes catastrophic climate change, plunging the Earth into a new ice age.

* The Arrival (1996) starring Charlie Sheen. Extraterrestrial aliens attempt to secretly cause global warming and thereby terraform Earth into an environment more suited to their needs.

* Waterworld (1995) starring Kevin Costner. Set in a future world, where the polar ice caps have melted due to global warming and the Earth is almost entirely covered with water.

Television

* South Park spoofed global warming in five episodes: Two Days Before the Day After Tomorrow, Spontaneous Combustion, Goobacks, Smug Alert! and Manbearpig.

* Star Trek: The Next Generation had two such global-warming themed episodes:
o Star Trek: The Next Generation episode Déjà Q (1990) - The crew suggests an artificial amplification of global warming using greenhouse gases to counter the cooling effects of dust from the impact of a moon on a planet.
o The Inner Light (1992) - Jean-Luc Picard lives a lifetime on a planet experiencing Global Warming and aridification. Ultimately the climate change becomes serious enough to threaten all life on the planet. This Hugo Award winner is among the 5 most popular out of all 178 episodes in the TNG series.

* The 1987 Teenage Mutant Ninja Turtles cartoon has four episodes dealing with global warming. In Shredder's Mom, Shredder and Krang use a mirror fixed to a satellite to warm up the Earth if the political leaders do not surrender to them. The Teenage Mutant Ninja Turtles get help from General Yogure to stop them. In Northern Lights Out a man named Eric Red in Norway plans to melt the polar ice cap and flood all the coastal cities on the Earth by blowing up underground volcanoes, which will make it "easy" for Eric Red and his gang to take over the Earth. In A Real Snow Job, set in the Alps in Austria, Krang and Shredder use a Zoetropic wave device to melt the worlds' ice, flooding the coastal cities and making the Earth easy for Krang and Shredder to take over. In Too Hot to Handle, Vernon Fenwick's nephew Foster has an invention that brings the Earth closer to the Sun, a "Solar Magnet".

* The 1980s Transformers animated series had at least one global-warming themed episode: "Revenge of Bruticus." There, the Combaticons (a faction of the series' main villains, the Decepticons, created by rebel Decepticon Starscream) use the Space Bridge device to hurl Earth toward the sun, hoping to destroy the Earth and all enemies. The Autobots are forced to help the humans endure the heat while putting aside their differences with the Decepticons in a race against time to restore Earth to its natural orbit.

Comic Books

* Teenage Mutant Ninja Turtles Adventures from Archie Comics. Set in their present (1980s/1990s), but also including time travels to a future, in which New York City is flooded because of global warming and the greenhouse effect.

Related Videos

* From Science to Time to Vanity Fair: Global Warming Becomes a Hot Topic. Lecture given by Amy Gajda, Assistant Professor of Journalism and Law, University of Illinois. February 8, 2007. University of Illinois at Urbana-Champaign.

From http://en.wikipedia.org/

Climate change denial

Climate change denial describes efforts to counter all or part of the theory of global climate change. While the term "climate skeptic" generally refers to scientists taking good faith positions on the global warming controversy, climate change denial usually refers to disinformation campaigns alleged to be promoted and funded by groups with a financial interest in misrepresenting the scientific consensus on climate change, particularly groups with ties to the energy lobby. Newsweek, as well as numerous journalists, including George Monbiot and Ellen Goodman, among others, describe it as a form of denialism.

Denial vs. skepticism

"Modern skepticism," according to Michael Shermer, editor of the scientific skepticism quarterly Skeptic, "is embodied in the scientific method, that involves gathering data to formulate and test naturalistic explanations for natural phenomena. A claim becomes factual when it is confirmed to such an extent it would be reasonable to offer temporary agreement." Terms such as "deny global warming" and "climate change denial" have been used since 2000 to describe business opposition to the current scientific consensus. Organizations such as the Global Climate Coalition, according to a leaked 1991 "strategy memo," set out not to gather data and test explanations, but to influence public perception of climate change science and "reposition global warming as theory rather than fact." The strategy was criticized as misrepresenting science in a 2006 Royal Society letter to ExxonMobil expressing disappointment that a recent industry publication "leaves readers with such an inaccurate and misleading impression of the evidence on the causes of climate change ... documented in the scientific literature."

The August 2007 Newsweek cover story "The Truth About Denial" reported that "this well-coordinated, well-funded campaign by contrarian scientists, free-market think tanks, and industry has created a paralyzing fog of doubt around climate change." Newsweek published a rebuttal piece by contributing editor Robert J. Samuelson, calling it "a vast oversimplification of a messy story" and "fundamentally misleading". He argues that "journalists should resist the temptation to portray global warming as a morality tale... in which anyone who questions its gravity or proposed solutions may be ridiculed".

Several commentators have compared climate change denial with Holocaust denial, whereas others have decried those comparisons as inappropriate.

Denial industry

"As soon as the scientific community began to come together on the science of climate change, the pushback began," according to University of California, San Diego historian Naomi Oreskes. Newsweek has reported that:

Individual companies and industry associations — representing petroleum, steel, autos and utilities, for instance — formed lobbying groups with names like the Global Climate Coalition and the Information Council on the Environment. ICE's game plan called for enlisting greenhouse doubters to "reposition global warming as theory rather than fact".

In 1998, John H. Cushman of the New York Times reported on a memorandum written by a public relations specialist for the American Petroleum Institute. The leaked memo described a plan "to recruit a cadre of scientists who share the industry's views of climate science and to train them in public relations so they can help convince journalists, politicians and the public that the risk of global warming is too uncertain to justify controls on greenhouse gases." As part of a US$ 5,000,000 strategy to "maximize the impact of scientific views consistent with ours on Congress, the media and other key audiences," the document mentioned:

A proposed media-relations budget of US $600,000, not counting any money for advertising, would be directed at science writers, editors, columnists and television network correspondents, using as many as 20 "respected climate scientists" recruited expressly "to inject credible science and scientific accountability into the global climate debate, thereby raising questions about and undercutting the 'prevailing scientific wisdom.'"

Several journalists have argued that the strategy resembles the one adopted by tobacco lobbyists after being confronted with new data linking cigarettes to cancer — to shift public perception of the discoveries toward that of a myth, unwarranted claim, or exaggeration rather than mainstream scientific theory. In 2006, The Guardian reported:

There are clear similarities between the language used and the approaches adopted by Philip Morris and by the organisations funded by Exxon. The two lobbies use the same terms, which appear to have been invented by Philip Morris's consultants. "Junk science" meant peer-reviewed studies showing that smoking was linked to cancer and other diseases. "Sound science" meant studies sponsored by the tobacco industry suggesting that the link was inconclusive. Both lobbies recognised that their best chance of avoiding regulation was to challenge the scientific consensus. As a memo from the tobacco company Brown and Williamson noted, "Doubt is our product since it is the best means of competing with the 'body of fact' that exists in the mind of the general public. It is also the means of establishing a controversy."

Former National Academy of Sciences president Dr.Frederick Seitz earned "approximately US$ 585,000" in the 70s and 80s as a consultant to R.J. Reynolds Tobacco Company while continuing "to draw a salary as 'president emeritus' at Rockefeller University". R.J. Reynolds contributed $45 million to the medical research co-ordinated by Seitz and others. Although the research did not touch upon the health effects of tobacco smoking, "the industry frequently ran ads in newspapers and magazines citing its multi-million-dollar research program as proof of its commitment to science—and arguing that the evidence on the health effects of smoking was mixed."

Seitz went on to chair groups such as the Science and Environmental Policy Project and the George C. Marshall Institute alleged to have made efforts to "downplay" global warming. Seitz stated in the 1980s that "Global warming is far more a matter of politics than of climate." He stated in an April 2006 interview that he believes "we're having a natural change, whatever that means, due to natural causes as yet unexplored." He elaborated by saying that "I would say it's unlikely that we face serious danger from global warming" and "Any good scientist would recognize that it cannot be ignored, but I think, under present circumstances, the only thing we can do is proceed as we are and wait to see what the result is." Seitz authored the Oregon Petition, a document published jointly by the Marshall and Oregon Institutes in opposition to the Kyoto protocol. The petition and accompanying "Research Review of Global Warming Evidence" claimed:

The proposed limits on greenhouse gases would harm the environment, hinder the advance of science and technology, and damage the health and welfare of mankind. There is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gases is causing or will, in the foreseeable future, cause catastrophic heating of the Earth's atmosphere and disruption of the Earth's climate. … We are living in an increasingly lush environment of plants and animals as a result of the carbon dioxide increase. Our children will enjoy an Earth with far more plant and animal life than that with which we now are blessed. This is a wonderful and unexpected gift from the Industrial Revolution.

The Guardian has reported that, in 1993, Philip Morris established the Advancement of Sound Science Coalition (TASSC) in conjunction with the APCO public relations firm as part of a plan to combat proposed regulation of secondhand smoke: "Philip Morris, APCO said, needed to create the impression of a 'grassroots' movement—one that had been formed spontaneously by concerned citizens to fight 'overregulation'. It should portray the danger of tobacco smoke as just one 'unfounded fear' among others, such as concerns about pesticides and cellphones." Within ten years, the group was also receiving funds from Exxon:

TASSC, the ‘coalition’ created by Philip Morris, was the first and most important of the corporate-funded organisations denying that climate change is taking place. It has done more damage to the campaign to halt it than any other body.

Several think tanks funded by Exxon or, later, ExxonMobil, to contest climate change have also reputedly received funding from Philip Morris such as the Competitive Enterprise Institute, the Cato Institute, the Heritage Foundation, the Hudson Institute, the Frontiers of Freedom Institute, the Reason Foundation, George Mason University's Law and Economics Center, and the Independent Institute.

A survey carried out by the Royal Society found that in 2005 ExxonMobil distributed $2.9m to 39 groups that the society said "misrepresented the science of climate change by outright denial of the evidence".

Instances of climate change denial

Public sector

A report by NASA's Office of the Inspector General has revealed that personnel in the agency's public affairs office were guilty of "inappropriate political interference" in their attempts to play down climate change findings.

In 1994, according to a leaked memo, the influential Republican strategist Frank Luntz advised members of the GOP, with regard to climate change, that "you need to continue to make the lack of scientific certainty a primary issue" and "challenge the science" by "recruiting experts who are sympathetic to your view." In 2006, Luntz stated that he still believes "back '97, '98, the science was uncertain", but he currently agrees with the scientific consensus.

In 2005, the New York Times reported that Philip Cooney, a former lobbyist and "climate team leader" at the American Petroleum Institute, had "repeatedly edited government climate reports in ways that play down links between such emissions and global warming, according to internal documents." The George W. Bush administration had hired Cooney in 2001 as chief of staff for the White House Council on Environmental Quality, "the office that helps devise and promote administration policies on environmental issues." The New York Times reported:

Climate experts and representatives of environmental groups, when shown examples of the revisions, said they illustrated the significant if largely invisible influence of Mr. Cooney and other White House officials with ties to energy industries that have long fought greenhouse-gas restrictions.

The newspaper also claimed that "fforts by the Bush administration to highlight uncertainties in science pointing to human-caused warming have put the United States at odds with other nations and with scientific groups at home." Cooney reportedly removed an entire section on climate in one report, whereupon an oil lobbyist sent him a fax saying "You are doing a great job."

Cooney announced his resignation two days after the story of his tampering with scientific reports broke. A few days later it was announced that Cooney would take up a position with ExxonMobil.

The Washington Post reported:

n April, the Supreme Court ... rebuked the administration for not regulating greenhouse gases associated with global warming, issuing its ruling less than two months after Cheney declared that 'conflicting viewpoints' remain about the extent of the human contribution to the problem.

Then-Vice President Dick Cheney's connections to the Energy Lobby, and to ExxonMobil in particular, have fueled speculation that his characterization of climate change science is linked to the "denial industry." In 2000, Cheney’s Energy Task Force, officially known as the National Energy Policy Development Group, invited the executives of various major oil companies, including Exxon, Conoco, BP, and Royal Dutch Shell, to consult with the White House regarding the development of a national energy policy, although this was initially denied by the participating companies. An Exxon lobbyist - among others - was thanked by the U.S. Undersecretary of Global Affairs for Exxon's role in convincing President Bush to reject the Kyoto accords. According to the Union of Concerned Scientists:

In her talking points for a 2001 meeting with a group that included ExxonMobil lobbyist Randy Randol (uncovered through a Freedom of Information Act request), U.S. Undersecretary for Global Affairs Paula Dobriansky thanked the group for their input on global warming policy, noting, ‘POTUS rejected Kyoto, in part, based on input from you.’

The Government Accountability Project's "Climate Science Watch" has questioned the administration's appointment of officials with private-sector ties to climate change denial:

Jeffrey Salmon is the Associate Under Secretary for Science at the U.S. Department of Energy. Prior to moving to DOE, from 1991–2001 he was Executive Director of the George C. Marshall Institute, a key actor in the global warming disinformation campaign. In 1998 he participated in the development of a now-notorious oil industry-sponsored plan to wage a campaign against the mainstream science community on global warming. Before that, he was senior speechwriter for Dick Cheney, when Cheney was Secretary of Defense. The Office of Science oversees roughly $4 billion a year in DOE-supported research, including a roughly $140 million climate change research budget. What does Salmon do in this position—for example, on matters of climate change research, assessment, and communication?

Private Sector

After the IPCC released its February 2007 report, the American Enterprise Institute reportedly offered British, American, and other scientists $10,000, plus travel expenses, to publish articles critical of the assessment. The institute, which had received more than $US 1.6 million from Exxon and whose vice-chairman of trustees is Lee Raymond, former head of Exxon, sent letters that "attack the UN's panel as 'resistant to reasonable criticism and dissent and prone to summary conclusions that are poorly supported by the analytical work' and ask for essays that 'thoughtfully explore the limitations of climate model outputs'." More than 20 AEI employees have worked as consultants to the George W. Bush administration. Despite her initial conviction that with "the overwhelming science out there, the deniers' days were numbered," Democratic Senator Barbara Boxer said that when she learned of the AEI's offer, "I realized there was a movement behind this that just wasn't giving up."

The British Royal Society conducted a survey that found ExxonMobil had given US$ 2.9 million to American groups that "misinformed the public about climate change," 39 of which "misrepresented the science of climate change by outright denial of the evidence". In 2006, the British Royal Society issued a demand that ExxonMobil withdraw funding for climate change denial. The letter, which was leaked to the media, drew criticism, notably from Timothy Ball and others, who argued the society attempted to "politicize the private funding of science and to censor scientific debate."

ExxonMobil has denied the accusations that it has been trying to mislead the public about global warming:

"The recycling of this type of discredited conspiracy theory diverts attention from the real challenge at hand: how to provide the energy needed to improve global living standards while also reducing greenhouse gas emissions."

Kivalina v. ExxonMobil

On February 26, 2008, attorneys for the Native American Rights Fund and the Center on Race, Poverty & the Environment brought suit against ExxonMobil Corporation and two dozen other members of the energy lobby, including BP, Chevron, ConocoPhillips, and Royal Dutch Shell. The complaint seeks to recover damages for the destruction of Kivalina, Alaska, a village which "is being forced to relocate because of flooding caused by the changing Arctic climate." (The U.S. Army Corps of Engineers determined in 2006 that Kivalina residents would be forced to relocate, at a minimum cost of US$95m, as soon as 2016.). According to Stephan Faris, a writer for The Atlantic, the Kivalina suit accuses ExxonMobil et al.

"of conspiring to cover up the threat of man-made climate change, in much the same way the tobacco industry tried to conceal the risks of smoking — by using a series of think tanks and other organizations to falsely sow public doubt in an emerging scientific consensus."

Kivalina v. ExxonMobil is reported to be the first climate-change lawsuit with "a discretely identifiable victim."

Possible effects of climate change denial
See also: Individual and political action on climate change

Former Democratic Senator Tim Wirth has claimed that the denial effort affected both the Congressional political climate as well as the general public opinion. "They patterned what they did after the tobacco industry. Both figured, sow enough doubt, call the science uncertain and in dispute. That's had a huge impact on both the public and Congress." In an interview with the journal Science, physicist and U.S. Representative Rush Holt called the opposition in the climate debate a "denial machine":

"...for more than two decades scientists have been issuing warnings that the release of greenhouse gases, principally carbon dioxide (CO2), is probably altering Earth's climate in ways that will be expensive and even deadly. The American public yawned and bought bigger cars. Statements by the American Association for the Advancement of Science, American Geophysical Union, American Meteorological Society, Intergovernmental Panel on Climate Change, and others underscored the warnings and called for new government policies to deal with climate change. Politicians, presented with noisy statistics, shrugged, said there is too much doubt among scientists, and did nothing."

A 2006 Newsweek poll reported that only one third of Americans believed climate change is "mainly caused by things people do" and 64 percent believed scientists disagree "a lot" about it. A 2007 Newsweek poll found 42 percent of the general public believed scientists disagree "a lot" that "human activities are a major cause of global warming." A May 2007 CNN poll, in contrast, found a 54 percent majority agree with the IPCC that "Global warming is a proven fact and is mostly caused by emissions from cars and industrial facilities such as power plants and factories." A 2007 CBS News poll found that 49 percent think "global warming is having a serious impact now" and 36 percent think it "will in the future". It also reported that 78 percent of Americans "think that it is necessary to take steps to counter global warming right away".

Robert J. Samuelson in Newsweek has argued that "Global warming has clearly occurred; the hard question is what to do about it."Former Australian Prime Minister John Howard has asserted that "human ingenuity, directed towards clean technology and wise institutional design, remains our best weapon against climate change." Alexander Cockburn of The Nation accused "climate spokesmen" such as Al Gore of being "shills" for nuclear energy, arguing that "the best documented conspiracy of interest is between the fearmongers and the nuclear industry" and "Hysteria rules the day, drowning useful initiatives such as environmental cleanup, while smoothing the way for the nuclear industry to reap its global rewards." Carbon taxes such as the one advocated by Al Gore as Vice President have faced bipartisan Congressional opposition. House Natural Resources Committee Chairman Nick J. Rahall II, Democrat, stated that "That's going to be passed on; the consumer would end up paying for that."

American public opinion is relatively split on possible measures to combat global warming. A March 2006 ABC News poll found that "Six in 10 think much can be done to reduce both the amount of global warming", but it also found that only 45 percent think that government should require "Cars that use less gasoline" and only 42 percent think it should require "Appliances that use less electricity". However, the poll's opinions regarding voluntary measures are far more positive, even though 56 percent "oppose giving companies tax breaks to build nuclear power plants". A CBS News poll reported that Americans support some compulsory regulations, for example, 64 percent would be willing to pay higher gasoline taxes if the money is used for renewable energy research. Peter Aldhous at New Scientist has argued that "policies to combat global warming can command majority public support in the US, as long as they don't hit people's pockets too hard."

From http://en.wikipedia.org/

Climate change

Climate change is any long-term change in the statistics of weather over durations ranging from decades to millions of years. It can be manifest in changes to averages, extremes, or other statistical measures, and may occur in a specific region or for the Earth as a whole.

In recent usage, especially in the context of environmental policy, climate change usually refers to changes in modern climate (see global warming). For information on temperature measurements over various periods, and the data sources available, see temperature record. For attribution of climate change over the past century, see attribution of recent climate change.

Causes of climate change

Factors that can shape climate are often called climate forcings. These include such processes as variations in solar radiation, deviations in the Earth's orbit, and changes in greenhouse gas concentrations. There are a variety of climate change feedbacks that can either amplify or diminish the initial forcing. Some parts of the climate system, such as the oceans and ice caps, respond slowly in reaction to climate forcing because of their large mass. Therefore, the climate system can take centuries or longer to fully respond to new external forcings.

Plate tectonics

On the longest time scales, plate tectonics repositions continents, shapes oceans, builds and tear down mountains and generally defines the stage upon which climate exists. During the Carboniferous period, plate tectonics may have triggered the large-scale storage of carbon and increased glaciation. More recently, plate motions have been implicated in the intensification of the present ice age when, approximately 3 million years ago, the North and South American plates collided to form the Isthmus of Panama. This shut off direct mixing between the Atlantic and Pacific Oceans.

Solar output

Variations in solar activity during the last several centuries based on observations of sunspots and beryllium isotopes.

The sun is the source of the energy input to the climate system. Early in Earth's history, according to one theory, the sun was too cold to support liquid water at the Earth's surface, leading to what is known as the Faint young sun paradox. Over the coming millions of years, the sun will continue to brighten and produce a correspondingly higher energy output; as it continues through what is known as its "main sequence", and the Earth's atmosphere will be affected accordingly.

Solar output also varies on shorter time scales, including the 11-year solar cycle and longer-term modulations. The 11-year sunspot cycle produces only a small change in temperature near Earth's surface (on the order of a tenth of a degree) but has a greater influence in the atmosphere's upper layers. Solar intensity variations are considered to have been influential in triggering the Little Ice Age, and for some of the warming observed from 1900 to 1950. The cyclical nature of the sun's energy output is not yet fully understood; it differs from the very slow change that is happening within the sun as it ages and evolves, with some studies pointing toward solar radiation increases from cyclical sunspot activity affecting global warming

Orbital variations

In their effect on climate, orbital variations are in some sense an extension of solar variability, because slight variations in the Earth's orbit lead to changes in the distribution and abundance of sunlight reaching the Earth's surface. These orbital variations, known as Milankovitch cycles, directly affect glacial activity. Eccentricity, axial tilt, and precession comprise the three dominant cycles that make up the variations in Earth's orbit. The combined effect of the variations in these three cycles creates changes in the seasonal reception of solar radiation on the Earth's surface. As such, Milankovitch Cycles affecting the increase or decrease of received solar radiation directly influence the Earth's climate system, and influence the advance and retreat of Earth's glaciers. Subtler variations are also present, such as the repeated advance and retreat of the Sahara desert in response to orbital precession.

Volcanism

Volcanism is the process of conveying material from the depths of the Earth to the surface. Volcanic eruptions, geysers and hot springs are all part of the volcanic process and all release gases and particulates into the atmosphere.

Eruptions large enough to affect climate occur on average several times per century, and cause cooling for a period of a few years. The eruption of Mount Pinatubo in 1991, the second largest terrestrial eruption of the 20th century (after the 1912 eruption of Novarupta) affected the climate substantially. Global temperatures decreased by about 0.5 °C (0.9 °F), and ozone depletion being temporarily substantially increased. Much larger eruptions, known as large igneous provinces, occur only a few times every hundred million years, but can reshape climate for millions of years and cause mass extinctions. Initially, it was thought that the dust ejected into the atmosphere from large volcanic eruptions was responsible for longer-term cooling by partially blocking the transmission of solar radiation to the Earth's surface. However, measurements indicate that most of the dust hurled into the atmosphere may return to the Earth's surface within as little as six months, given the right conditions.

Volcanoes are also part of the extended carbon cycle. Over very long (geological) time periods, they release carbon dioxide from the Earth's interior, counteracting the uptake by sedimentary rocks and other geological carbon dioxide sinks. According to the US Geological Survey, however, estimates are that human activities generate more than 130 times the amount of carbon dioxide emitted by volcanoes.

Ocean variability

The ocean is a fundamental part of the climate system. Short-term fluctuations (years to a few decades) such as the El Niño–Southern Oscillation, the Pacific decadal oscillation, the North Atlantic oscillation, and the Arctic oscillation, represent climate variability rather than climate change. On longer time scales, alterations to ocean processes such as thermohaline circulation play a key role in redistributing heat by carrying out a very slow and extremely deep movement of water, and the long-term redistribution of heat in the world's oceans.

Human influences

Anthropogenic factors are human activities that change the environment. In some cases the chain of causality of human influence on the climate is direct and unambiguous (for example, the effects of irrigation on local humidity), whilst in other instances it is less clear. Various hypotheses for human-induced climate change have been argued for many years though, generally, the scientific debate has moved on from scepticism to a scientific consensus on climate change that human activity is the probable cause for the rapid changes in world climate in the past several decades. Consequently, the debate has largely shifted onto ways to reduce further human impact and to find ways to adapt to change that has already occurred.

Of most concern in these anthropogenic factors is the increase in CO2 levels due to emissions from fossil fuel combustion, followed by aerosols (particulate matter in the atmosphere) and cement manufacture. Other factors, including land use, ozone depletion, animal agriculture[1and deforestation, are also of concern in the roles they play - both separately and in conjunction with other factors - in affecting climate.

Physical evidence for climatic change

Evidence for climatic change is taken from a variety of sources that can be used to reconstruct past climates. Reasonably complete global records of surface temperature are available beginning from the mid-late 1800s. For earlier periods, most of the evidence is indirect—climatic changes are inferred from changes in indicators that reflect climate, such as vegetation, ice cores, dendrochronology, sea level change, and glacial geology.

Glaciers

Glaciers are recognized as being among the most sensitive indicators of climate change,[1advancing during climate cooling (for example, during the period known as the Little Ice Age) and retreating during climate warming on moderate time scales. Glaciers grow and shrink, both contributing to natural variability and amplifying externally forced changes. A world glacier inventory has been compiled since the 1970s. Initially based mainly on aerial photographs and maps, this compilation has resulted in a detailed inventory of more than 100,000 glaciers covering a total area of approximately 240,000 km2 and, in preliminary estimates, for the recording of the remaining ice cover estimated to be around 445,000 km2. The World Glacier Monitoring Service collects data annually on glacier retreat and glacier mass balance From this data, glaciers worldwide have been shown to be shrinking significantly, with strong glacier retreats in the 1940s, stable or growing conditions during the 1920s and 1970s, and again increasing rates of ice loss from the mid 1980s to present. Mass balance data indicate 17 consecutive years of negative glacier mass balance.

The most significant climate processes of the last several million years are the glacial and interglacial cycles of the present age. The present interglaciation (often termed the Holocene) has lasted about 10,000 years. Shaped by orbital variations, earth-based responses such as the rise and fall of continental ice sheets and significant sea-level changes helped create the climate. Other changes, including Heinrich events, Dansgaard–Oeschger events and the Younger Dryas, however, illustrate how glacial variations may also influence climate without the forcing effect of orbital changes.

Advancing glaciers leave behind moraines that contain a wealth of material - including organic matter that may be accurately dated - recording the periods in which a glacier advanced and retreated. Similarly, by tephrochronological techniques, the lack of glacier cover can be identified by the presence of soil or volcanic tephra horizons whose date of deposit may also be precisely ascertained. Glaciers are considered one of the most sensitive climate indicators by the IPCC, and their recent observed variations are considered a prominent indicator of impending climate change. See also Retreat of glaciers since 1850.

Vegetation

A change in the type, distribution and coverage of vegetation may occur given a change in the climate; this much is obvious. In any given scenario, a mild change in climate may result in increased precipitation and warmth, resulting in improved plant growth and the subsequent sequestration of airborne CO2. Larger, faster or more radical changes, however, may well result in vegetation stress, rapid plant loss and desertification in certain circumstances.

Ice cores

Analysis of ice in a core drilled from a permafrost area, such as the Antarctic, can be used to show a link between temperature and global sea level variations. The air trapped in bubbles in the ice can also reveal the CO2 variations of the atmosphere from the distant past, well before modern environmental influences. The study of these ice cores has been a significant indicator of the changes in CO2 over many millennia, and continue to provide valuable information about the differences between ancient and modern atmospheric conditions.

Dendrochronology

Dendochronology is the analysis of tree ring growth patterns to determine the age of a tree. From a climate change viewpoint, however, Dendochronology can also indicate the climatic conditions for a given number of years. Wide and thick rings indicate a fertile, well-watered growing period, whilst thin, narrow rings indicate a time of lower rainfall and less-than-ideal growing conditions.

Pollen analysis

Palynology is the study of contemporary and fossil palynomorphs, including pollen. Palynology is used to infer the geographical distribution of plant species, which vary under different climate conditions. Different groups of plants have pollen with distinctive shapes and surface textures, and since the outer surface of pollen is composed of a very resilient material, they resist decay. Changes in the type of pollen found in different sedimentation levels in lakes, bogs or river deltas indicate changes in plant communities; which are dependent on climate conditions.

Insects

Remains of beetles are common in freshwater and land sediments. Different species of beetles tend to be found under different climatic conditions. Given the extensive lineage of beetles whose genetic makeup has not altered significantly over the millennia, knowledge of the present climatic range of the different species, and the age of the sediments in which remains are found, past climatic conditions may be inferred.

Sea level change

Global sea level change for much of the last century has generally been estimated using tide gauge measurements collated over long periods of time to give a long-term average. More recently, altimeter measurements — in combination with accurately determined satellite orbits — have provided an improved measurement of global sea level change.

From http://en.wikipedia.org/

Clathrate gun hypothesis

The clathrate gun hypothesis is the popular name given to the hypothesis that rises in sea temperatures (and/or falls in sea level) can trigger the sudden release of methane from methane clathrate compounds buried in the seabeds and their permafrost, which, because the methane itself is a powerful greenhouse gas, in turn causes further temperature rise and further methane clathrate destabilization – in effect initiating a runaway process, as irreversible once started as the firing of a gun.

In its original form, the hypothesis proposed that the "clathrate gun" could cause abrupt runaway warming in a timescale less than a human lifetime, and might be responsible for warming events in and at the end of the last ice age. This is now thought unlikely.

However there is stronger evidence that runaway methane clathrate breakdown may have caused drastic alteration of the ocean environment and the atmosphere of earth on a number of occasions in the past, over timescales of tens of thousands of years; most notably in connection with the Permian extinction event, when 96% of all marine species became extinct 251 million years ago.

Mechanism

Methane clathrate, also known incorrectly as methane hydrate, is a form of water ice that contains a large amount of methane within its crystal structure. Extremely large deposits of methane clathrate have been found under sediments on the ocean floors of the Earth. The sudden release of large amounts of natural gas from methane clathrate deposits in runaway climate change could be a cause of past, future, and present climate changes. The release of this trapped methane is a potential major outcome of a rise in temperature; it is thought that this is a main factor in the global warming of 6°C that happened during the end-Permian extinction, as methane is much more powerful as a greenhouse gas than carbon dioxide (despite its atmospheric lifetime of around 12 years, it has a global warming potential of 62 over 20 years and 23 over 100 years). The theory also predicts this will greatly affect available oxygen content of the atmosphere.

Possible release events

Two events possibly linked in this way are the Permian-Triassic extinction event and the Paleocene-Eocene Thermal Maximum. It may also have had a role in the sudden warm-up of "Snowball Earth", 630 million years ago. However, warming at the end of the last ice age is thought not to be due to methane release.

Related mechanism: dissolved methane release

Focusing on the Permian-Triassic boundary, Gregory Ryskin explores the possibility that mass extinction can be caused by an extremely fast, explosive release of dissolved methane (and other dissolved gases such as carbon dioxide and hydrogen sulfide) that accumulated in the oceanic water masses prone to stagnation and anoxia (e.g., in silled basins).

Current outlook

Most deposits of methane clathrate are in sediments too deep to respond rapidly, and modelling by Archer (2007) suggests the methane forcing should remain a minor component of the overall greenhouse effect. Clathrate deposits destabilize from the deepest part of their stability zone, which is typically hundreds of metres below the seabed. A sustained increase in sea temperature will warm its way through the sediment eventually, and cause the deepest, most marginal clathrate to start to break down; but it will typically take of the order of a thousand years or more for the temperature signal to get through.

One exception, however, may be in clathrates associated with the Arctic ocean, where clathrates can exist in shallower water stabilized by lower temperatures rather than higher pressures; these may potentially be marginally stable much closer to the surface of the sea-bed, stabilized by a frozen 'lid' of permafrost preventing methane escape. Recent research carried out in 2008 in the Siberian Arctic has shown millions of tons of methane being released, apparently through perforations in the seabed permafrost, with concentrations in some regions reaching up to 100 times normal. The excess methane has been detected in localized hotspots in the outfall of the Lena River and the border between the Laptev Sea and the East Siberian Sea. Some melting may be the result of geological heating, but more thawing is believed to be due to the greatly increased volumes of meltwater being discharged from the Siberian rivers flowing north. Current methane release has previously been estimated at 0.5 Mt per year. Shakhova et al. (2008) estimate that not less than 1,400 Gt of Carbon is presently locked up as methane and methane hydrates under the Arctic submarine permafrost, and 5-10% of that area is subject to puncturing by open taliks. They conclude that "release of up to 50 Gt of predicted amount of hydrate storage highly possible for abrupt release at any time". That would increase the methane content of the planet's atmosphere by a factor of twelve, equivalent in greenhouse effect to a doubling in the current level of CO2.

In 2008 the United States Department of Energy National Laboratory system and the United States Geological Survey's Climate Change Science Program both identified potential clathrate destabilization in the Arctic as one of four most serious scenarios for abrupt climate change, which have been singled out for priority research. The USCCSP released a report in late December 2008 estimating the gravity of this risk.

Possible outcomes

According to Gregory Ryskin, a sudden release of methane from the ocean may lead to either global cooling or global warming. The explosions and burning of methane would produce lots of smoke and dust, which would lead to global cooling. The methane and carbon dioxide would "create the greenhouse effect, which may lead to global warming". Professor Ryskin writes that it is "difficult to predict" whether global cooling or warming would result.

The evolution of dust and smoke, if it caused global cooling would likely only last a short time before the particulates washed out of the atmosphere. Then the raised levels of Methane and the derivative Carbon Dioxide would take over. The likely result would be a flick-flack of extra cold and extra warm years, arguably more devestating to crop production than a trend in one direction or the other.

It may be possible to explain past marine extinctions by the scrubbing effect. If an inert gas is bubbled through water, the surface of each bubble acts as a semi permeable membrane. Gases diffuse across this membrane according to their concentration inside and outside the bubble. The result of bubbling methane through the ocean is to scrub out the oxygen, leading to ocean anoxia.

The consequences of a methane-driven oceanic eruption for marine and terrestrial life are likely to be catastrophic. Figuratively speaking, the erupting region "boils over," ejecting a large amount of methane and other gases (e.g., CO2, H2S) into the atmosphere, and flooding large areas of land. Whereas pure methane is lighter than air, methane loaded with water droplets is much heavier, and thus spreads over the land, mixing with air in the process (and losing water as rain). The air-methane mixture is explosive at methane concentrations between 5% and 15%; as such mixtures form in different locations near the ground and are ignited by lightning, explosions and conflagrations destroy most of the terrestrial life, and also produce great amounts of smoke and of carbon dioxide. Firestorms carry smoke and dust into the upper atmosphere, where they may remain for several years; the resulting darkness and global cooling may provide an additional kill mechanism. Conversely, carbon dioxide and the remaining methane create the greenhouse effect, which may lead to global warming. The outcome of the competition between the cooling and the warming tendencies is difficult to predict.

In fiction

* The book Mother of Storms by John Barnes offers a fictional example of catastrophic climate change caused by methane clathrate release.
* In The Life Lottery by Ian Irvine unprecedented seismic activity triggers a release of methane hydrate, reversing global cooling.
* The hypothesis is the basis of an experiment in the Playstation 2 game Death By Degrees.
* In Transcendent by Stephen Baxter, averting such a crisis is a major plotline.
* The novel The Black Silent by author David Dun features this idea as a key scientific point.
* In the anime Ergo Proxy, a string of explosions in the methane hydrate reserves wipes out 85% of human life on Earth.
* The novel The Far Shore of Time by Frederik Pohl features an alien race attempting to destroy humanity by bombing the methane clathrate reserves, thus releasing the gas into the atmosphere.

From http://en.wikipedia.org/

Carbon dioxide in the Earth's atmosphere

Carbon dioxide forms approximately 0.04% of the Earth's atmosphere. It is essential to photosynthesis in plants and other photoautotrophs, and is also a prominent greenhouse gas.

Concentration



As of November 2007, the CO2 concentration in Earth's atmosphere was about 0.0384% by volume, or 384 parts per million by volume (ppmv). This is 100 ppmv (35%) above the 1832 ice core levels of 284 ppmv.There is an annual fluctuation of about 3–9 ppmv which roughly follows the Northern Hemisphere's growing season. The Northern Hemisphere dominates the annual cycle of CO2 concentration because it has much greater land area and plant biomass than the Southern Hemisphere. Concentrations peak in May as the Northern Hemisphere spring greenup begins and reach a minimum in October when the quantity of biomass undergoing photosynthesis is greatest.

Despite its relatively small concentration overall in the atmosphere, CO2 is an important component of Earth's atmosphere because it absorbs and emits infrared radiation at wavelengths of 4.26 µm (asymmetric stretching vibrational mode) and 14.99 µm (bending vibrational mode), thereby playing a role in the greenhouse effect. See also "Carbon dioxide equivalent".



The initial carbon dioxide in the atmosphere of the young Earth was produced by volcanic activity. This was essential for a warm and stable climate conducive to life. Volcanic activity now releases about 130 to 230 teragrams (145 million to 255 million short tons) of carbon dioxide each year, which is less than 1% of the amount released by human activities.



Burning fossil fuels such as coal and petroleum is the leading cause of increased anthropogenic CO2; deforestation is the second major cause. As of 2004, around 27 gigatonnes of CO2 are released from fossil fuels per year worldwide, equivalent to about 7.4 gigatonnes of carbon (see List of countries by carbon dioxide emissions); in 2006 8.4 gigatonnes carbon were emitted . With some simple calculations based on the surface area of the Earth, normal atmospheric pressure, and an estimate of roughly 400ppmv atmospheric CO2 content one can calculate that the atmospheric CO2 content is currently approximately 3 teratonnes.

Carbon dioxide is released to the atmosphere by a variety of natural sources, and over 95% of total CO2 emissions would occur even if humans were not present on Earth. For example, the natural decay of organic material in forests and grasslands, such as dead trees, results in the release of about 220 gigatonnes of carbon dioxide every year. This carbon dioxide alone is over 8 times the amount emitted by humans. Although natural sources represent most CO2 emissions, they do not contribute to the recent observed increase in concentrations because natural sources are balanced by natural sinks that remove carbon dioxide from the atmosphere.The increase in carbon dioxide concentration arises because the increase from human activity is not completely balanced by a corresponding sink.



In 1997, Indonesian peat fires may have released 13% – 40% as much carbon as fossil fuel burning does in a single year. Various techniques have been proposed for removing excess carbon dioxide from the atmosphere in carbon dioxide sinks. Not all the emitted CO2 remains in the atmosphere; some is absorbed in the oceans or biosphere. The ratio of the increase in atmospheric CO2 to emitted CO2 is known as the airborne fraction (Keeling et al., 1995); this varies for short-term averages but is typically about 45% over longer (5 year) periods.

Increased amounts of CO2 in the atmosphere enhance the greenhouse effect. It is currently the predominant scientific opinion that carbon dioxide emissions are the main cause of global warming observed since the mid-20th century. The effect of combustion-produced carbon dioxide on climate is occasionally called the Callendar effect, after engineer and inventor Guy Stewart Callendar who proposed this association in 1938.

Origins

Natural sources of atmospheric carbon dioxide include volcanic outgassing, the combustion of organic matter, and the respiration processes of living aerobic organisms; man-made sources of carbon dioxide include the burning of fossil fuels for heating, power generation and transport, as well as some industrial processes such as cement making. It is also produced by various microorganisms from fermentation and cellular respiration. Plants convert carbon dioxide to carbohydrates during a process called photosynthesis. They produce the energy needed for this reaction through the photolysis of water. The resulting gas, oxygen, is released into the atmosphere by plants, which is subsequently used for respiration by heterotrophic organisms, forming a cycle.

During the 100,000 year ice age cycle, CO2 varies between a low of approximately 200 ppm during cold periods and a high of 280 ppm during interglacials. Recent human influences have increased this to above 380 ppm. There is a large natural flux of CO2 into and out of the biosphere and oceans. In the pre-industrial era these fluxes were largely in balance. Currently about 57% of human-emitted CO2 is removed by the biosphere and oceans; without this effect CO2 levels would be even higher.

Historical variation



The most direct method for measuring atmospheric carbon dioxide concentrations for periods before direct sampling is to measure bubbles of air (fluid or gas inclusions) trapped in the Antarctic or Greenland ice caps. The most widely accepted of such studies come from a variety of Antarctic cores and indicate that atmospheric CO2 levels were about 260 – 280 ppmv immediately before industrial emissions began and did not vary much from this level during the preceding 10,000 years (10 kyr).

The longest ice core record comes from East Antarctica, where ice has been sampled to an age of 800 kyr BP (Before Present). During this time, the atmospheric carbon dioxide concentration has varied by volume between 180 – 210 ppm during ice ages, increasing to 280 – 300 ppm during warmer interglacials.

One study disputed the claim of stable CO2 levels during the present interglacial of the last 10 kyr. Based on an analysis of fossil leaves, Wagner et al. argued that CO2 levels during the period 7 – 10 kyr ago were significantly higher (~300 ppm) and contained substantial variations that may be correlated to climate variations. Others have disputed such claims, suggesting they are more likely to reflect calibration problems than actual changes in CO2. Relevant to this dispute is the observation that Greenland ice cores often report higher and more variable CO2 values than similar measurements in Antarctica. However, the groups responsible for such measurements (e.g., Smith et al.) believe the variations in Greenland cores result from in situ decomposition of calcium carbonate dust found in the ice. When dust levels in Greenland cores are low, as they nearly always are in Antarctic cores, the researchers report good agreement between Antarctic and Greenland CO2 measurements.



On longer timescales, various proxy measurements have been used to attempt to determine atmospheric carbon dioxide levels millions of years in the past. These include boron and carbon isotope ratios in certain types of marine sediments, and the number of stomata observed on fossil plant leaves. While these measurements give much less precise estimates of carbon dioxide concentration than ice cores, there is evidence for very high CO2 volume concentrations between 200 and 150 Ma of over 3,000 ppm and between 600 and 400 Ma of over 6,000 ppm. On long timescales, atmospheric CO2 content is determined by the balance among geochemical processes including organic carbon burial in sediments, silicate rock weathering, and vulcanism. The net effect of slight imbalances in the carbon cycle over tens to hundreds of millions of years has been to reduce atmospheric CO2. The rates of these processes are extremely slow; hence they are of limited relevance to the atmospheric CO2 response to emissions over the next hundred years. In more recent times, atmospheric CO2 concentration continued to fall after about 60 Ma, and there is geochemical evidence that volume concentrations were less than 300 ppm by about 20 Ma. Low CO2 concentrations may have been the stimulus that favored the evolution of C4 plants, which increased greatly in abundance between 7 and 5 Ma. Present carbon dioxide levels are likely higher now than at any time during the past 20 Ma and certainly higher than in the last 800,000.

Relationship with oceanic concentration



The Earth's oceans contain a huge amount of carbon dioxide in the form of bicarbonate and carbonate ions — much more than the amount in the atmosphere. The bicarbonate is produced in reactions between rock, water, and carbon dioxide. One example is the dissolution of calcium carbonate:

CaCO3 + CO2 + H2O ⇌ Ca2+ + 2 HCO3-

Reactions like this tend to buffer changes in atmospheric CO2. Since the right-hand side of the reaction produces an acidic compound, adding CO2 on the left-hand side decreases the pH of sea water. Reactions between carbon dioxide and non-carbonate rocks also add bicarbonate to the seas. This can later undergo the reverse of the above reaction to form carbonate rocks, releasing half of the bicarbonate as CO2. Over hundreds of millions of years this has produced huge quantities of carbonate rocks.

The vast majority of CO2 added to the atmosphere will eventually be absorbed by the oceans and become bicarbonate ion. The process takes on the order of a hundred years because most seawater rarely comes near the surface.

As the oceans warm, carbon dioxide solubility in the surface waters decreases markedly. However, the overall system is quite complex, as indicated above, and further details may be found in the article on the carbon solubility pump.

An unknown, though probably large, quantity of CO2 is in the ocean sediments as a methane-carbon dioxide-water clathrates, one of the family of gas hydrates.

From http://en.wikipedia.org/