November 3, 2017

The U.S. Global Change Research Program (USGCRP) released a draft of the highly-anticipated Fourth National Climate Assessment (NCA4) for public comment on November 3. The NCA is a quadrennial scientific assessment, which analyzes the impacts of both human-induced and natural global climate change, mandated by Congress in the Global Change Research Act (GCRA) of 1990.

The fourth NCA is being developed in two volumes, and is expected to be completed in December 2018. Volume I, the Climate Science Special Report (CSSR), assesses the physical science of climate change, with a focus on the United States. The CSSR summarizes the best-available science on observed and projected climate changes, and intends to serve as the foundation for efforts to assess climate-related risks and inform decision-making. Of note, the report finds that the global average sea level has risen by about 7-8 inches in the last 115 years, with over half of that rise occurring since 1993, and the annual average surface temperature over the contiguous United States has increased by about 1.8 degrees Fahrenheit over the same period. Volume II of the NCA4 is an assessment of the impacts, risks, and adaptation across the United States.

A revised draft of the report will undergo final agency clearance following further review by hundreds of independent scientists spanning various disciplines and fields of expertise, including experts from the National Academy of Sciences, and consideration of any public comments received.

Public comments on the draft assessment must be submitted online by January 31, 2018.

Sources: Cornell Law School, U.S. Global Change Research Program