National Academy of Sciences, NAS: ”There are well-understood physical mechanisms by which changes in the amounts of greenhouse gases cause climate changes.”
American Association for the Advancement of Science, AAAS: “The vast preponderance of evidence, based on years of research conducted by a wide array of different investigators at many institutions, “…clearly indicates that global climate change is real, it is caused largely by human activities”
American Chemical Society, ACS: ”The Earth’s climate is changing in response to increasing concentrations of greenhouse gases (GHGs) and particulate matter in the atmosphere, largely as the result of human activities.”
American Meteorological Society, AMS: ”It is clear from extensive scientific evidence that the dominant cause of the rapid change in climate of the past half century is human-induced increases in the amount of atmospheric greenhouse gases”
American Geophysical Union, AGU: ”Humans are responsible, through the release of carbon dioxide (CO2) and other greenhouse pollutants, for most of the increase in global average temperatures over the past half century.”
Meteorological Office, UK: ”However, global temperatures have risen significantly over the 20th and 21st centuries, driven primarily by the rise in atmospheric carbon dioxide”
Royal Meteorological Society, UK: ”The evidence we have is that it is overwhelmingly the result of changes to the composition of the atmosphere – the growth in so called greenhouse gases”
French Academy of Science: ”This increase is mainly due to the increase in CO2 concentration in the atmosphere. The increase in CO2 and, to a lesser degree, of other greenhouse gases, is unequivocally due to human activity.”
Kungliga Vetenskapsakademin: ”Isotope records show that the CO2 increase is primarily related to anthropogenic emissions in contrast to earlier periods in Earth’s history. Most of the increase is due to the burning of fossil fuels, but about 20% is due to land use change, including deforestation and biomass burning”
American Medical Association: … supports the findings of the Intergovernmental Panel on Climate Change’s fourth assessment report and concurs with the scientific consensus that the Earth is undergoing adverse global climate change and that anthropogenic contributions are significant.
American Physical Society: The evidence is incontrovertible: Global warming is occurring. If no mitigating actions are taken, significant disruptions in the Earth’s physical and ecological systems, social systems, security and human health are likely to occur. We must reduce emissions of greenhouse gases beginning now.
The Geological Society of America: global climate has warmed and that human activities (mainly greenhouse‐gas emissions) account for most of the warming since the middle 1900s.
U.S. National Academy of Sciences: ”The scientific understanding of climate change is now sufficiently clear to justify taking steps to reduce the amount of greenhouse gases in the atmosphere.” (2005)
U.S. Global Change Research Program: The global warming of the past 50 years is due primarily to human-induced increases in heat-trapping gases.