Climate is the long-term weather pattern in a region, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorological variables that are commonly measured are temperature, humidity, atmospheric pressure, wind, and precipitation. In a broader sense, climate is the state of the components of the climate system, including the atmosphere, hydrosphere, cryosphere, lithosphere and biosphere and the interactions between them. The climate of a location is affected by its latitude, longitude, terrain, altitude, land use and nearby water bodies and their currents.
Global Warming Potential (GWP) is an index to measure of how much infrared thermal radiation a greenhouse gas would absorb over a given time frame after it has been added to the atmosphere. The GWP makes different greenhouse gases comparable with regards to their "effectiveness in causing radiative forcing". It is expressed as a multiple of the radiation that would be absorbed by the same mass of added carbon dioxide, which is taken as a reference gas. Therefore, the GWP is one for CO2. For other gases it depends on how strongly the gas absorbs infrared thermal radiation, how quickly the gas leaves the atmosphere, and the time frame being considered.
The Intergovernmental Panel on Climate Change (IPCC) is an intergovernmental body of the United Nations. Its job is to advance scientific knowledge about climate change caused by human activities. The World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) established the IPCC in 1988. The United Nations endorsed the creation of the IPCC later that year. It has a secretariat in Geneva, Switzerland, hosted by the WMO. It has 195 member states who govern the IPCC. The member states elect a bureau of scientists to serve through an assessment cycle. A cycle is usually six to seven years. The bureau selects experts to prepare IPCC reports. It draws the experts from nominations by governments and observer organizations. The IPCC has three working groups and a task force, which carry out its scientific work.
Sir Robert Tony Watson CMG FRS is a British chemist who has worked on atmospheric science issues including ozone depletion, global warming and paleoclimatology since the 1980s. Most recently, he is lead author of the February 2021 U.N. report Making Peace with Nature.
The Special Report on Emissions Scenarios (SRES) is a report by the Intergovernmental Panel on Climate Change (IPCC) that was published in 2000. The greenhouse gas emissions scenarios described in the Report have been used to make projections of possible future climate change. The SRES scenarios, as they are often called, were used in the IPCC Third Assessment Report (TAR), published in 2001, and in the IPCC Fourth Assessment Report (AR4), published in 2007. The SRES scenarios were designed to improve upon some aspects of the IS92 scenarios, which had been used in the earlier IPCC Second Assessment Report of 1995. The SRES scenarios are "baseline" scenarios, which means that they do not take into account any current or future measures to limit greenhouse gas (GHG) emissions.
Climate Change 2007, the Fourth Assessment Report (AR4) of the United Nations Intergovernmental Panel on Climate Change (IPCC), was published in 2007 and is the fourth in a series of reports intended to assess scientific, technical and socio-economic information concerning climate change, its potential effects, and options for adaptation and mitigation. The report is the largest and most detailed summary of the climate change situation ever undertaken, produced by thousands of authors, editors, and reviewers from dozens of countries, citing over 6,000 peer-reviewed scientific studies. People from over 130 countries contributed to the IPCC Fourth Assessment Report, which took six years to produce. Contributors to AR4 included more than 2,500 scientific expert reviewers, more than 800 contributing authors, and more than 450 lead authors.
The Science Subcommittee on Technology is one of six subcommittees of the United States House Committee on Science and Technology.
Roger S. Pulwarty is a scientist from Trinidad and Tobago and contributed to the work of the Intergovernmental Panel on Climate Change (IPCC). Pulwarty is the Senior Scientist in the National Oceanic and Atmospheric Administration (NOAA) Physical Sciences Laboratory in Boulder, Colorado.
Richard "Rich" Gayle Richels directs global climate change research at the Electric Power Research Institute. Richels received a BS degree in physics from the College of William & Mary. He was awarded MS and PhD degrees in decision science from Harvard University's Division of Applied Sciences.
Greenhouse gases (GHGs) are the gases in the atmosphere that raise the surface temperature of planets such as the Earth. What distinguishes them from other gases is that they absorb the wavelengths of radiation that a planet emits, resulting in the greenhouse effect. The Earth is warmed by sunlight, causing its surface to radiate heat, which is then mostly absorbed by greenhouse gases. Without greenhouse gases in the atmosphere, the average temperature of Earth's surface would be about −18 °C (0 °F), rather than the present average of 15 °C (59 °F).
Christopher B. Field is an American scientist and researcher, who has contributed to the field of climate change. The author of more than 200 scientific publications, Field's research emphasizes impacts of climate change, from the molecular to the global scale. His work includes major field experiments on responses of California grassland to multi-factor global change, integrative studies on the global carbon cycle, and assessments of impacts of climate change on agriculture. Field's work with models includes studies on the global distribution of carbon sources and sinks, and studies on environmental consequences of expanding biomass energy.
A climate change scenario is a hypothetical future based on a "set of key driving forces". Scenarios explore the long-term effectiveness of mitigation and adaptation. Scenarios help to understand what the future may hold. They can show which decisions will have the most meaningful effects on mitigation and adaptation.
Michael Calvin MacCracken, has been chief scientist for climate change programs with the Climate Institute in Washington, D.C., since 2002; he was also elected to its board of directors in 2006.
The Science Subcommittee on Environment is one of five subcommittees of the United States House Committee on Science, Space and Technology.
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."
William R. Moomaw is the Professor Emeritus of International Environmental Policy at the Fletcher School, Tufts University. Moomaw has worked at the intersection of science and policy, advocating for international sustainable development. His activities have included being a long-time contributor to the Intergovernmental Panel on Climate Change and an author on the seminal "Perspective" paper on proforestation.
The Sixth Assessment Report (AR6) of the United Nations (UN) Intergovernmental Panel on Climate Change (IPCC) is the sixth in a series of reports which assess scientific, technical, and socio-economic information concerning climate change. Three Working Groups covered the following topics: The Physical Science Basis (WGI); Impacts, Adaptation and Vulnerability (WGII); Mitigation of Climate Change (WGIII). Of these, the first study was published in 2021, the second report February 2022, and the third in April 2022. The final synthesis report was finished in March 2023.
Paola Andrea Arias Gómez is a climate scientist and professor at the Environmental School of the University of Antioquia (Colombia). Her research includes different aspects of climate change and hydroclimate modeling in Colombia and South America. Arias is the first Colombian woman to be selected as an author for an IPCC report, participating as lead author for Working Group I of the IPCC Sixth Assessment Report.
Ronald J. Stouffer is a meteorologist and adjunct professor at the University of Arizona, formerly Senior Research Climatologist and head of the Climate and Ecosystems Group at the Geophysical Fluid Dynamics Laboratory (GFDL), part of NOAA. He has also served on the faculty of Princeton University.
