There is a nearly unanimous scientific consensus that the Earth has been consistently warming since the start of the Industrial Revolution, that the rate of recent warming is largely unprecedented, and that this warming is mainly the result of a rapid increase in atmospheric carbon dioxide (CO2) caused by human activities. The human activities causing this warming include fossil fuel combustion, cement production, and land use changes such as deforestation, with a significant supporting role from the other greenhouse gases such as methane and nitrous oxide. This human role in climate change is considered "unequivocal" and "incontrovertible".
Michael Evan Mann is an American climatologist and geophysicist. He is the director of the Center for Science, Sustainability & the Media at the University of Pennsylvania. Mann has contributed to the scientific understanding of historic climate change based on the temperature record of the past thousand years. He has pioneered techniques to find patterns in past climate change and to isolate climate signals from noisy data.
Roy Warren Spencer is an American meteorologist. He is a principal research scientist at the University of Alabama in Huntsville, and the U.S. Science Team leader for the Advanced Microwave Scanning Radiometer (AMSR-E) on NASA's Aqua satellite. He has served as senior scientist for climate studies at NASA's Marshall Space Flight Center. He is known for his satellite-based temperature monitoring work, for which he was awarded the American Meteorological Society's Special Award. Spencer disagrees with the scientific consensus that most global warming in the past 50 years is the result of human activity, instead believing that anthropogenic greenhouse gas emissions have caused some warming, but that influence is small compared to natural variations in global average cloud cover.
Willi Dansgaard was a Danish paleoclimatologist. He was Professor Emeritus of Geophysics at the University of Copenhagen and a member of the Royal Danish Academy of Science and Letters, the Royal Swedish Academy of Sciences, the Icelandic Academy of Sciences, and the Danish Geophysical Society.
Sir David Anthony King is a South African-born British chemist, academic, and head of the Climate Crisis Advisory Group (CCAG).
Sir John Theodore Houghton was a Welsh atmospheric physicist who was the co-chair of the Intergovernmental Panel on Climate Change's (IPCC) scientific assessment working group which shared the Nobel Peace Prize in 2007 with Al Gore. He was lead editor of the first three IPCC reports. He was professor in atmospheric physics at the University of Oxford, former Director General at the Met Office and founder of the Hadley Centre.
The Second Assessment Report (SAR) of the Intergovernmental Panel on Climate Change (IPCC), published in 1995, is an assessment of the then available scientific and socio-economic information on climate change. The report was split into four parts: a synthesis to help interpret UNFCCC article 2, The Science of Climate Change, Impacts, Adaptations and Mitigation of Climate Change, Economic and Social Dimensions of Climate Change. Each of the last three parts was completed by a separate Working Group (WG), and each has a Summary for Policymakers (SPM) that represents a consensus of national representatives.
Jonathan Michael Gregory is a climate modeller working on mechanisms of global and large-scale change in climate and sea level on multidecadal and longer timescales at the Met Office and the University of Reading.
Philip Douglas Jones is a former director of the Climatic Research Unit (CRU) and a professor in the School of Environmental Sciences at the University of East Anglia (UEA) from 1998, having begun his career at the unit in 1976. He retired from these positions at the end of 2016, and was replaced as CRU director by Tim Osborn. Jones then took up a position as a Professorial Fellow at the UEA from January 2017.
Andrew John Pitman is a British-Australian atmospheric scientist.
Peter A. Stott MBE is a climate scientist who leads the Climate Monitoring and Attribution team of the Hadley Centre for Climate Prediction and Research at the Met Office in Exeter, UK. He is an expert on anthropogenic and natural causes of climate change.
Hans Joachim "John" Schellnhuber is a German atmospheric physicist, climatologist and founding director of the Potsdam Institute for Climate Impact Research (PIK) and former chair of the German Advisory Council on Global Change (WBGU). Since 1 December 2023, Schellnhuber is the Director General of IIASA.
The Climatic Research Unit email controversy began in November 2009 with the hacking of a server at the Climatic Research Unit (CRU) at the University of East Anglia (UEA) by an external attacker, copying thousands of emails and computer files to various internet locations several weeks before the Copenhagen Summit on climate change.
Julia Mary Slingo is a British meteorologist and climate scientist. She was Chief Scientist at the Met Office from 2009 until 2016. She is also a visiting professor in the Department of Meteorology at the University of Reading, where she held, prior to appointment to the Met Office, the positions of Director of Climate Research in the Natural Environment Research Council (NERC) National Centre for Atmospheric Science and founding director of the Walker Institute for Climate System Research.
The Oeschger Centre for Climate and Climate Change Research (OCCR) is the interdisciplinary centre of excellence for climate research of the University of Bern.
Thomas F. Stocker is a Swiss climate scientist.
The contributions of women in climate change have received increasing attention in the early 21st century. Feedback from women and the issues faced by women have been described as "imperative" by the United Nations and "critical" by the Population Reference Bureau. A report by the World Health Organization concluded that incorporating gender-based analysis would "provide more effective climate change mitigation and adaptation."
Kim M. Cobb is an American climate scientist, who is professor of Environment and Society and professor of Earth, Environmental and Planetary Sciences at Brown University, where she directs the Institute at Brown for Environment and Society. Cobb was previously a professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology. She is particularly interested in oceanography, geochemistry and paleoclimate modeling.
Pete Smith is Professor of Soils and Global change at the University of Aberdeen where he directs the Scottish Climate Change Centre of Expertise, ClimateXChange.
