List of climate change controversies

The global warming controversy is a long-running dispute about human effects - past, present and future - on climate. The starting point is whether there has been significant global warming caused by industrial emissions of carbon dioxide. But this alone would be a scientific argument confined to the scientific press. The point that leads to major controversy - because it could have significant economic impacts - is whether action (usually, restrictions on the use of fossil fuels to reduce CO2 emmissions) should be taken now or in the near future.

"Proponents"' position

Supporters of the global warming theory assert that:

• the IPCC reports correctly summarise the state of climate science
• the historical temperature record shows a rise of 0.4-0.8 oC over the last 100 years
• this rise is unprecedented in the temperature record of the past 1000 years
• climate models can reproduce this trend, but only when using greenhouse gas forcing [1]
• attribution of recent global warming shows that the rise can be attributed to human emissions of greenhouse gases
• climate models predict more warming, and other climate effects (sea level rise, etc) in the future
• there is a scientific consensus behind all of the above
• humankind is performing a great geophysical experiment and if it turns out badly - however that is defined - we cannot undo it.

"Proponents" of global warming tend to support the IPCC position and thus represent a broadly unified viewpoint, though with considerable differences over what action should be taken. Optionally, supporters may go on to point out that there is a good chance that the future changes may be undesirable, and that planning to avoid or mitigate them would be a good idea.

Opponents' position

• Earth's climate has been both colder and warmer than today, and these changes are adequately explained by mechanisms that do not involve human greenhouse gas emissions.
• There is no significant global warming relative to the expected natural trends.
• A small amount of global warming would be benign or even beneficial.
• Climate science can not make definitive predictions yet, since the computer models used to make these predictions are still evolving and do not yet take into account recently discovered feedback mechanisms.
• Global warming studies have errors or have not been reproduced.

Members of this faction give more weight to data such as paleoclimatic studies, temperature measurements made from weather balloons, and satellites which they claim show less warming than surface land and sea records.

"Opponents" tend to define themselves in terms of opposition to the IPCC position and do not have a unified viewpoint *for* anything.

Scope of the controversy

The controversy occurs almost entirely within the press and political arenas. In the scientific press and amongst climate researchers, there is little "controversy" about global warming, only a desire to investigate a scientific problem and determine its consequences. As Kevin E. Trenberth writes:

In 1995 the IPCC assessment concluded that "the balance of evidence suggests that there is a discernible human influence on global climate". Since then the evidence has become much stronger --- from the recent record warmth, the improved paleo-record that provides context, improved modeling and simulation of the past climate, and improved statistical analysis. Thus the headline in IPCC (2001) is "There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities". The best assessment of the global warming contribution is that the human climate signal emerged from the noise of background variability in the late 1970s. Biggest impact is likely to be making the extremes more extreme. While some changes arising from global warming are benign or even beneficial, the economic effects of the weather extremes are substantial and clearly warrant attention in policy debates... Consequently, there is a strong case for slowing down the projected rates of climate change from human influences. [2]

Trenberth also provides evidence for the controversy that occurs when science meets the political arene:

The SPM was approved line by line by governments... The argument here is that the scientists determine what can said, but the governments determine how it can best be said. Negotiations occur over wording to ensure accuracy, balance, clarity of message, and relevance to understanding and policy. The IPCC process is dependent on the good will of the participants in producing a balanced assessment. However, in Shanghai, it appeared that there were attempts to blunt, and perhaps obfuscate, the messages in the report, most notably by Saudi Arabia. This led to very protracted debates over wording on even bland and what should be uncontroversial text... The most contentious paragraph in the IPCC (2001) SPM was the concluding one on attribution. After much debate the following was carefully crafted: "In the light of new evidence, and taking into account the remaining uncertainties, most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations."[3]

Support for GWT

Supporters of the global warming theory (GWT) assert that amongst climate researchers, there is little "controversy" about global warming but rather a "scientific consensus" of support for it. They say that GWT opponents are vastly outnumbered by those who accept the IPCC position, for example only 2 of the 120 contributing authors to the IPCC TAR report are known to have voiced any complaint.

Moreover, they assert that the pronouncements of the United Nations climate panel (IPCC) objectively and thoroughly represent the current state of scientific knowledge on climate change.

Opposition to GWT

Scientists who oppose the global warming theory point out that the predictions of atmospheric warming made by various GW models have consistently failed to agree with actual temperature measurements. For example, during the period 1979 to 1998 when theory predicted a sharp rise in temperature, there was a mild cooling trend instead (see John Christy, et al.). Opponents of GWT are fond of looking at the satellite temperature record only for those portions that support their opposition. They fail to notice that the full record shows warming, currently of 0.082 °C/decade; or that Christy's version is but one of several and "just happens" to be the one to give the lowest trends.

Public policy organiziations which oppose the GWT assert that supporters have misrepresented the findings of the IPCC and ignored the extent to which its contributors and lead authors have publicly disagreed with its "summary for policymakers". However, only 2 of 120 lead authors of the most recent report have complained, and they were skeptics anyway.

Both sides on the controversy have accused each other of willfully ignoring data and analysis which undermines their own positions.

A number of scientists with backgrounds in climate research dispute the global warming theory (GWT), notably Richard Lindzen, John Christy, Patrick Michaels, Fred Singer, Robert Balling and Sherwood Idso.

These scientists who oppose the GWT are referred to as "skeptics". Moreover, some say that the scientists mentioned above don't deserve such a mild label as "skeptics" since they are are closer to "denialists" who refuse to objectively examine the evidence (see also global warming skepticism).

The IPCC science working group agrees that there are significant successes and problems with the simulations which are used to predict climate, while opponents assert that the report summaries omit the negative aspects (see IPCC) and mostly report progress is being made in understanding climate.

Also, a number of conservative think tanks oppose the theory (see Science and Environmental Policy Project).

Support of industry-backed organizations (such as the Global Climate Coalition and the Greening Earth Society) for these scientists' skepticism is taken by some as evidence against their contention that the theory is unproven. If the fossil-fuel industry is assumed to always value profit above scientific rigor, then the integrity of any scientist funded by that industry is assumed to be compromised, especially if that scientist's views are favorable to the continued health of fossil-fuel industry. Some critics of environmentalist politics see this argument as an indirect ad hominem attack on the scientists mentioned above. Since a profound understanding of paleoclimatic conditions is required to successfully pursue fossil fuel exploration and production, some of the foremost experts in the Earth's climatic history are employed in the oil and gas industry.

Uncertainty

A degree of uncertainty remains. Some believe that the present warming trend shown by some land-based weather stations, marine observations, borehole thermometry, and satellite observations is likely to continue or increase, fueled by the emission of carbon dioxide and other gases which are believed to be "greenhouse gases". Others argue that solar activity plays a much bigger role in climate change and question whether the human influence is even discernible.

Magnitude of warming

Uncertainty also remains about the likely magnitude of future global warming (the IPCC suggests a range of 1.4 to 5.8 °C between 1990 and 2100 [4]) and its environmental impacts. Environmentalists and other advocates fear that the impacts will be profound. If warming were to continue at the present rate, there would be adverse changes in ocean circulation, catastrophic global climate change, loss of biodiversity and irreversible damage to agriculture in those ecoregions most affected. In some regions, e.g. Western Europe and Bangladesh, damage is projected to be extreme, due to loss of Gulf Stream warming and global sea level rise respectively. More frequent bouts of destructive weather are also anticipated, and risk experts in the insurance industry have expressed very strong concerns, advocating a proactive approach based on the precautionary principle. Estimates accepted by the IPCC and by some insurance industry bodies estimate up to 3.5 billion people could be affected by rising disease, loss of fresh water supply, and other impacts.

Opposition

In opposition stand the fossil fuel industry and independent skeptics, who question theories of human-caused global warming as well as action to mitigate Global Warming. They generally argue that the economic costs of making changes to avoid increased CO2 emissions would be too large, implicitly assuming that economic models are more accurate than climate models - an assertion with little backing. They also argue that healthy economies are required to fund technologically innovative solutions. US president George W. Bush made this argument in rejecting the Kyoto Protocol. Bush did not reject the science outright, but argued that the greenhouse gas control was a matter of voluntary restraint by industry. However, many countries have rejected these arguments and have signed up to the Kyoto Protocol. Also, many U.S. states have nonetheless put strong controls on greenhouse gases.

Standoff

This standoff has made the scientific questions difficult to distinguish from political ones.

Counting experts

The proportion of scientists who support or oppose any of the global warming theories is a matter of controversy in its own right (see scientific opinion of global warming). Environmentalists and their allies claim virtually unanimous support for the global warming theory from the scientific community. Opponents maintain that it is the other way around, claiming that the overwhelming majority of scientists either dismiss global warming altogether or merely consider it "unproven" (see global warming skepticism).

Arguments around the world

The arguments over global warming are viewed differently in different parts of the world. In Europe for example the environmentalist argument over Global warming has gained wider acceptance than in other parts of the world, most notably North America.

Cause or effect

Some scientists point out that global warming correlates closely with natural factors, especially solar activity. The balance is attributed to the action of humans (see anthropogenic global warming). How much warming is natural versus man-made has been debated since the 1990s by scientists, politicians, and advocacy organizations.

Beneficial or detrimental

There is also disagreement on whether the effects of global warming will be beneficial or detrimental. Many researchers predict disastrous consequences for a warming of 1.5 to 7 degrees Celsius. The UN's Intergovernmental Panel on Climate Change (IPCC) predicts such a warming is likely within the 21st century, unless severe measures are taken (see Kyoto Protocol).

Other researchers feel that up to 1.5 degrees Celsius of warming would increase crop yields and stabilize weather. Many of these doubt a larger warming is likely. In response, some advocates of strong early measures (well beyond Kyoto) note that the belief in beneficial effects and the doubt that a large warming is possible should be independent if these conclusions were in fact neutrally derived from scientific research.

Wait and see

Others suggest that a "wait and see" strategy disadvantages 3.5 billion people in favor of narrow advantage for a few growing regions and developed nations. However, those others have not provided details for their claims nor the advantages given to the other 3 billion people.

An unstable world

New findings have suggested that the earth's climate system is inherently unstable, and that global warming could thus precipitate non-linear sudden climate shifts, as have been discovered to have occurred within the earth's past. Ocean circulation, believed to be the key to such climate shifts, has been observed to be slowing, causing alarm among oceanographers. As briefly mentioned before some scientists fear that the Gulf Stream which conveys warm water from the Caribbean Sea across the Atlantic Ocean and is partly responsible for the relative mildness of northern Europe's climate (though other factors also predominate: [5]). There is a fear that it could be reduced or stopped altogether by the decreased salt content in the sea water, which would result from global warming. Which could cause temperatures in northern europe to drop.

The US National Academy of Sciences issued a report on this phenomenon in 2002, titled Abrupt Climate Change - Inevitable Surprises.[6] "It is important not to be fatalistic about the threats posed by abrupt climate change," it stated. "Societies have faced both gradual and abrupt climate changes for millennia and have learned to adapt through various mechanisms, such as moving indoors, developing irrigation for crops, and migrating away from inhospitable regions. Nevertheless, because climate change will likely continue in the coming decades, denying the likelihood or downplaying the relevance of past abrupt events could be costly."

Historical temperature record

There is also disagreement on the historical temperature record.

Recent reports

However, the US National Academy of Sciences, both in its 2002 report to President George W. Bush, and in its latest publications, has strongly endorsed evidence of an average global temperature increase in the 20th century and stated that human activity is heavily implicated in causing this increase. The American Meteorological Society (AMS statement), the American Geophysical Union (AGU statement), and other scientific societies have issued similar declarations. John Christy, who is usually placed in the skeptics camp, has signed the AGU statement on climate change.

Advocates of the global warming hypothesis who predict adverse consequences from as little as 1.5 degrees Celsius of warming nearly all support the Kyoto Protocol as a countermeasure. Details of the agreement are in the article about the Kyoto Protocol, including both the pollution and fiscal requirements.