USGCRP plays a vital coordinating role in international scientific assessments that provide policymakers with regular updates on the state of global change science on a planetary scale.

The United States is a substantial contributor to the intellectual content of Intergovernmental Panel on Climate Change (IPCC) reports, with well over 100 writing team members serving during the Sixth Assessment Report (AR6) cycle. The U.S. Government routinely provides comprehensive reviews of the draft reports, involving a process open to the public, hundreds of targeted reviewers, and convened expert panels to ensure rigor of submitted comments. USGCRP also provides travel support to facilitate non-federal U.S. scientist participation in international assessment activities, including the IPCC, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, the Arctic Council, and the United Nations Environment Programme Ozone Assessment Panels (Scientific and Environmental Effects).

In 2021, USGCRP facilitated the U.S. Government review of the IPCC Working Group II and III contributions to the AR6 report and preparations for review of the AR6 Synthesis Report, initiated in January 2022. IPCC Working Group I delivered its report for the AR6 cycle, Climate Change 2021: The Physical Science Basis, in August 2021. USGCRP assisted in managing the virtual U.S. delegation to the plenary session for approval of the Working Group I report, and in communicating key takeaways.