What is the National Climate Assessment?

The National Climate Assessment (NCA), mandated under the Global Change Research Act of 1990, is a major product of the U.S. Global Change Research Program. This quadrennial assessment is an important resource for understanding and communicating climate change science and impacts in the United States. It informs the Nation about observed changes, the current status of the climate, and anticipated trends for the future. The NCA process integrates scientific information from multiple sources and sectors to highlight key findings and significant gaps in our knowledge. NCA findings provide input to Federal science priorities and are used by policymakers, communities, and businesses as they navigate the challenges of climate and global change.

The Fourth NCA (NCA4) was released in two volumes. Volume I, known as the Climate Science Special Report, can be read at science2017.globalchange.gov. NCA4 Vol. II, Impacts, Risks, and Adaptation in the United States, can be read at nca2018.globalchange.gov