IPCC was created by the World Meteorological Organization (WMO) and the United Nations Environmental Program (UNEP). The role of the IPCC is to assess on a comprehensive basis the scientific, technical and socio-economic information relevant to understanding the scientific basis of risk of human-induced climate change. The IPCC produced "assessment reports" in 1990, 1995, 2001 and 2007. Hundreds of experts from all over the world contribute to the reports as authors, contributors and reviewers. They are nominated by governments, participating organizations or are sought directly by the IPCC for there specific expertise.

The IPCC does not make position a position statement. Their mission is to provide an information source for policy makers, and the general population. Visit their web site - see "Summaries for Policymakers".

The ‘Academy of Science’ of a given country is generally considered to be the elite of its scientific community. The US Academy of Science has only 2,100 nominated and elected members. Prior to the G8 summit in June 2007, the Academies of Science from all G8 countries (US, UK, France, Germany, Canada, Russia, Japan & Italy) plus six others (Brazil, Australia, China, India, Mexico & South Africa) issued a joint statement on global warming. Quotes -

• It is unequivocal that the climate is changing, and it is very likely that this is predominantly caused by the increasing human interference with the atmosphere.
• Our present energy course is not sustainable. World population is forecast to reach 9 billion by 2050, with the most rapid growth in the poorest countries. … Responding to this demand while minimizing further climate change will need all the determination and ingenuity we can muster.

• The American Meteorological Society

• There is adequate evidence from observations and interpretations of climate simulations to conclude that the atmosphere, ocean and land surface are warming; that humans have significantly contributed to this change; and that further climate change will continue to have important impacts on human societies, on economies, on ecosystems, and on wildlife through the 21^st century and beyond.
• Increasing air temperature will reduce snow pack, shift snowmelt timing, reduce crop production and rangeland fertility, and cause continued melting of the ice caps and sea level rise.

• US National Research Council

• The changes observed over the last several decades are likely mostly due to human activities.
• IPCC's conclusion that most of the observed warming of the last 50 years is likely to have been due to the increase in greenhouse gas concentrations accurately reflects the current thinking of the scientific community on this issue.

• American Geophysical Union
  also endorsed by the American Institute of Physics and the American Astronomical Society

• Human activities are increasingly altering the Earth's climate. … Scientific evidence strongly indicates that natural influences cannot explain the rapid increase in global near-surface temperatures observed during the second half of the 20th century.

• American Association for the Advancement of Science

• The scientific evidence is clear: global climate change caused by human activities is occurring now, and it is a growing threat to society.

• Geological Society of America

• The GSA supports the scientific conclusions that Earth’s climate is changing; the climate changes are due in part to human activities … the potential implications of global climate change and the time scale over which such changes will likely occur require active, effective, long-term planning."

• American Chemical Society

• There is now general agreement among scientific experts that the recent warming trend is real, that most of the observed warming is likely due to increased atmospheric greenhouse gas concentrations, and that climate change could have serious adverse effects by the end of this century.

• Union of Concerned Scientists

• Global warming is one of the most serious challenges facing us today.
• Global warming is caused by emissions of carbon dioxide and other heat-trapping gases that are emitted primarily by the burning of fossil fuels and the clearing of forests.
• The evidence is vast and the urgency of taking action becomes clearer with every new scientific study.

One scientific organization that disputed the conclusion that global warming is human caused in a 1999 statement – the American Association of Petroleum Geologists. However, due in part to dissent from "a significant number of our members," the AAPG is currently revising their position to "respect the conclusions" of scientific organizations listed above.

US-CAP is a coalition of major US corporations (AIG, Alcoa, BP America, Caterpillar, Dow Chemical, Duke Energy, DuPont, FLP Group, Ford, General Electric, General Motors, Johnson & Johnson, Lehman Brothers, Marsh Inc., PG&E, Shell, Siemans, Xerox and others) with several environmental groups (Environmental Defense, National Wildlife Fed., The Nature Conservancy & Pew Center on Global Climate Change). Their Call for Action states

• Each year we delay action to control emissions increases the risk of unavoidable consequences that could necessitate even steeper reductions in the future, at potentially greater economic cost and social disruption.
• In our view, the climate change challenge will create more economic opportunities than risks for the US economy.
• We need a mandatory, flexible climate program. Cap and Trade is Essential.
  
  (Note: "Cap and Trade" is a regulatory approach that caps total pollution, but allows companies to trade pollution credits when they reduce beyond their mandatory cap. The first cap and trade regulation was the 1990 extension of the US Clean Air Act for controlling sulfur dioxide from power plants, the cause of acid rain.)