Scientists questioning the accuracy of IPCC climate projections
Judith Curry, American climatologist, chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology.
Freeman Dyson, professor emeritus of the School of Natural Sciences, Institute for Advanced Study; Fellow of the Royal Society.
Richard Lindzen, Alfred P. Sloan professor of atmospheric science at the Massachusetts Institute of Technology and member of the National Academy of Sciences.
Nils-Axel Mörner, retired head of the Paleogeophysics and Geodynamics department at Stockholm University, former chairman of the INQUA Commission on Sea Level Changes and Coastal Evolution (1999–2003), and author of books supporting the validity of dowsing.
Garth Paltridge, retired chief research scientist, CSIRO Division of Atmospheric Research and retired director of the Institute of the Antarctic Cooperative Research Centre.
Philip Stott, professor emeritus of biogeography at the University of London.
Hendrik Tennekes, retired director of research, Royal Netherlands Meteorological Institute
Scientists arguing that global warming is primarily caused by natural processes
Khabibullo Abdusamatov, mathematician and astronomer at Pulkovo Observatory of the Russian Academy of Sciences.
Sallie Baliunas, astronomer, Harvard-Smithsonian Center for Astrophysics.
Ian Clark, hydrogeologist, professor, Department of Earth Sciences, University of Ottawa.
Chris de Freitas, associate professor, School of Geography, Geology and Environmental Science, University of Auckland.
David Douglass, solid-state physicist, professor, Department of Physics and Astronomy, University of Rochester.
Don Easterbrook, emeritus professor of geology, Western Washington University.
William M. Gray, professor emeritus and head of the Tropical Meteorology Project, Department of Atmospheric Science, Colorado State University.
William Happer, physicist specializing in optics and spectroscopy, Princeton University.
William Kininmonth, meteorologist, former Australian delegate to World Meteorological Organization Commission for Climatology.
David Legates, associate professor of geography and director of the Center for Climatic Research, University of Delaware.
Tad Murty, oceanographer; adjunct professor, Departments of Civil Engineering and Earth Sciences, University of Ottawa.
Tim Patterson, paleoclimatologist and professor of geology at Carleton University in Canada.
Ian Plimer, professor emeritus of Mining Geology, the University of Adelaide.
Nicola Scafetta, research scientist in the physics department at Duke University.
Tom Segalstad, head of the Geology Museum at the University of Oslo.
Fred Singer, professor emeritus of environmental sciences at the University of Virginia.
Willie Soon, astrophysicist, Harvard-Smithsonian Center for Astrophysics.
Roy Spencer, principal research scientist, University of Alabama in Huntsville.
Henrik Svensmark, Danish National Space Center.
Jan Veizer, environmental geochemist, professor emeritus from University of Ottawa.
Scientists arguing that the cause of global warming is unknown
Syun-Ichi Akasofu, retired professor of geophysics and founding director of the International Arctic Research Center of the University of Alaska Fairbanks.
Claude Allègre, politician; geochemist, Institute of Geophysics (Paris).
Robert C. Balling, Jr., a professor of geography at Arizona State University.
John Christy, professor of atmospheric science and director of the Earth System Science Center at the University of Alabama in Huntsville, contributor to several IPCC.
Petr Chylek, space and remote sensing sciences researcher, Los Alamos National Laboratory.
David Deming, geology professor at the University of Oklahoma.
Antonino Zichichi, emeritus professor of nuclear physics at the University of Bologna and president of the World Federation of Scientists.
Scientists arguing that global warming will have few negative consequences
Craig D. Idso, faculty researcher, Office of Climatology, Arizona State University and founder of the Center for the Study of Carbon Dioxide and Global Change.
Sherwood Idso, former research physicist, USDA Water Conservation Laboratory, and adjunct professor, Arizona State University.
Patrick Michaels, senior fellow at the Cato Institute and retired research professor of environmental science at the University of Virginia