The IPCC – the acronym for Intergovernmental Panel on Climate Change – is the United Nations body for assessing the science related to climate change. It provides regular assessments on the scientific basis of climate change, its impacts and future risks, and options for adaptation and mitigation.
Find more information on the IPCC on the About page.
The IPCC assesses the thousands of scientific papers published each year to tell policymakers what we know and don’t know about the risks related to climate change. The IPCC identifies where there is agreement in the scientific community, where there are differences of opinion, and where further research is needed. Thus the IPCC offers policymakers a snapshot of what the scientific community understands about climate change rather than promoting a particular view. It does not do its own research, conduct climate measurements or produce its own climate models.
IPCC reports are policy-relevant without being policy-prescriptive. The IPCC may set out options for policymakers to choose from in pursuit of goals decided by policymakers, but it does not tell governments what to do.
Climate change is a change in the state of the climate that can be identified (e.g., by using statistical tests) by changes in the mean and/ or the variability of its properties and that persists for an extended period, typically decades or longer.
A complete definition is available in the Glossary of the Working Group I contribution to the Sixth Assessment Report (page 2222).
Climate change may be due to natural internal processes or external forcings such as modulations of the solar cycles, volcanic eruptions and persistent anthropogenic changes in the composition of the atmosphere or in land use.
Source: Glossary of the Working Group I contribution to the Sixth Assessment Report (Page 2222 under the definition of Climate Change)
Global warming refers to the increase in global surface temperature relative to a baseline reference period, averaging over a period sufficient to remove interannual variations (e.g., 20 or 30 years). A common choice for the baseline is 1850–1900 (the earliest period of reliable observations with sufficient geographic coverage), with more modern baselines used depending upon the application. See also Climate change and Climate variability.
Source: Glossary of the Working Group I contribution to the Sixth Assessment Report (page 2232)
The IPCC describes greenhouse gases (GHGs) as gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of radiation emitted by the Earth’s surface, by the atmosphere itself, and by clouds. This property causes the greenhouse effect. Water vapour (H2O), carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4 ) and ozone (O3) are the primary GHGs in the Earth’s atmosphere. Humanmade GHGs include sulphur hexafluoride (SF6 ), hydrofluorocarbons (HFCs), chlorofluorocarbons (CFCs) and perfluorocarbons (PFCs); several of these are also O3-depleting (and are regulated under the Montreal Protocol). See also Well-mixed greenhouse gas.
Source: Glossary of the Working Group I contribution to the Sixth Assessment Report (page 2233)
The greenhouse effect is the infrared radiative effect of all infrared-absorbing constituents in the atmosphere. Greenhouse gases (GHGs), clouds, and some aerosols absorb terrestrial radiation emitted by the Earth’s surface and elsewhere in the atmosphere. These substances emit infrared radiation in all directions, but, everything else being equal, the net amount emitted to space is normally less than would have been emitted in the absence of these absorbers because of the decline of temperature with altitude in the troposphere and the consequent weakening of emission. An increase in the concentration of GHGs increases the magnitude of this effect; the difference is sometimes called the enhanced greenhouse effect. The change in a GHG concentration because of anthropogenic emissions contributes to an instantaneous radiative forcing. Earth’s surface temperature and troposphere warm in response to this forcing, gradually restoring the radiative balance at the top of the atmosphere.
Source: Glossary of the Working Group I contribution to the Sixth Assessment Report (page 2232)
What is deforestation?
IPCC describes deforestation as the “conversion of forest to non-forest. [Note: For a discussion of the term forest and related terms such as afforestation, reforestation and deforestation, see the 2006 IPCC Guidelines for National Greenhouse Gas Inventories and their 2019 Refinement, and information provided by the United Nations Framework Convention 2226 Annex VII Glossary AVII on Climate Change (IPCC, 2006, 2019; UNFCCC, 2021a, b).]”
Source: Glossary of the Working Group I contribution to the Sixth Assessment Report (page 2225)
The IPCC describes fossil fuels as Carbon-based fuels from fossil hydrocarbon deposits, including coal, oil and natural gas.
Source: Glossary of the Working Group I contribution to the Sixth Assessment Report (page 2230)
According to the IPCC biodiversity or biological diversity means the variability among living organisms from all sources including, among other things, terrestrial, marine and other aquatic ecosystems, and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems (UN, 1992). See also Ecosystem and Ecosystem services.
Source: Glossary of the Working Group II contribution to the IPCC Sixth Assessment Report (page 2901)
Development that meets the needs of the present without compromising the ability of future generations to meet their own needs (WCED, 1987) and balances social, economic and environmental concerns. See also Development pathways and Sustainable Development Goals (SDGs).
Sustainable Development Goals (SDGs): – The 17 global goals for development for all countries established by the United Nations through a participatory process and elaborated in the 2030 Agenda for Sustainable Development, including ending poverty and hunger; ensuring health and well-being, education, gender equality, clean water and energy, and decent work; building and ensuring resilient and sustainable infrastructure, cities and consumption; reducing inequalities; protecting land and water ecosystems; promoting peace, justice and partnerships; and taking urgent action on climate change. See also Development pathways and Sustainable development.
Source: Glossary of the Working Group II contribution to the IPCC Sixth Assessment Report (page 2924)
Working Group I contribution to the IPCC Sixth Assessment Report
Working Group II contribution to the IPCC Sixth Assessment Report
Working Group III contribution to the IPCC Sixth Assessment Report
Special Report on Global Warming of 1.5°C
Special Report on Climate Change and Land
Special Report on the Ocean and Cryosphere in a Changing Climate