Fourth National Climate Assessment
This report was prepared as an update to the ongoing series of National Climate Assessments, conducted under the auspices of the Global Change Research Act of 1990
This report received collaborative guidance and review from over 300 federal and non-federal experts, including those representing state, local, and tribal governments, universities and academic institutions, and private organizations
This assessment illustrates the ways that the climate is changing throughout the United States, identifies both current and future risks to human communities and ecosystems, and provides recommendations for reducing those risks. By using up-to-date science to describe and model climate change, along with concrete examples of the impacts that are already being observed in the U.S. and the actions that have been taken to address them, this assessment presents stakeholders, decision-makers, and concerned citizens with resources to understand and mitigate the economic, social, and environment threat that climate change poses to current and future Americans.