What Is the Intergovernmental Panel on Climate Change?

The Intergovernmental Panel on Climate Change, known by the acronym IPCC, is the United Nations body that assesses the scientific, technical, and socioeconomic literature on climate change and reports its findings to governments. It was established in 1988 by the World Meteorological Organization and the UN Environment Programme, and its 195 member governments are drawn from the states that belong to the United Nations or the WMO. The panel conducts no original research and operates no observing systems of its own. Its output is an assessment: a structured evaluation of what the published literature does and does not establish, produced by volunteer author teams and reviewed by scientists and governments before release.

That distinction shapes everything about how the organization works. Because its reports are policy relevant but explicitly not policy prescriptive, the IPCC describes options and consequences without recommending a course of action. The IPCC's account of its own mandate and procedures sets out the rules governing author selection, review, and approval.

Structure and Working Groups

Assessment work is divided among three working groups. Working Group I covers the physical science basis, including radiative forcing, the carbon cycle, observed warming, and climate model projections. Working Group II covers impacts, adaptation, and vulnerability, from sea level rise on coastal infrastructure to shifts in agricultural yield. Working Group III covers mitigation, which is where most engineering content sits: energy system transitions, electricity generation and storage, industrial process emissions, transport, buildings, and carbon dioxide removal. A separate Task Force on National Greenhouse Gas Inventories maintains the methodologies that countries use to compile emissions accounts. Each working group is co-chaired by scientists from a developed and a developing country and supported by a small technical support unit. The World Meteorological Organization's description of the panel records the intergovernmental arrangement under which that structure operates.

The Assessment Cycle and Approval Process

The IPCC works in cycles lasting roughly six to seven years, each producing a report from every working group plus a synthesis report, along with special reports on topics governments request. Six full assessment cycles have been completed, the most recent culminating in the AR6 Synthesis Report in 2023. Drafting proceeds through two formal review rounds that draw tens of thousands of comments from expert reviewers and governments, each of which must receive a documented response. The underlying chapters are accepted as written by their authors, but the Summary for Policymakers is approved line by line in a plenary session where government delegates and lead authors negotiate wording that the science supports. The panel and former US Vice President Al Gore shared the 2007 Nobel Peace Prize for this body of work.

Scenarios, Inventories, and Technical Outputs

Two IPCC products are used directly by engineers and analysts. The first is the scenario framework, currently the Shared Socioeconomic Pathways combined with forcing levels, which supplies the standardized emissions and warming trajectories used in climate model intercomparison, infrastructure design studies, and financial risk disclosure. The second is the guidelines for national greenhouse gas inventories, which define emission factors and calculation tiers for sectors ranging from cement production to refrigerant leakage. Those guidelines are the accounting basis for reporting under the UN Framework Convention on Climate Change and for the Paris Agreement global stocktake.

Applications

Work produced by the IPCC is used in a wide range of technical and policy settings, including:

• National greenhouse gas inventory reporting and emissions accounting
• Climate scenario selection for infrastructure and grid planning studies
• Corporate and financial climate risk disclosure frameworks
• Adaptation planning for water resources, coastal defense, and agriculture
• Energy technology roadmaps and decarbonization pathway modeling
• University curricula and reference material in climate and energy engineering