The Congressionally-mandated National Climate Assessment is conducted every four years to assess and inform the Nation about the impacts of climate change. The U.S. Global Change Research Program coordinates a team of Federal and non-Federal authors in producing this comprehensive assessment of present and future climate impacts on the United States, and response options. Building on the success of the third, and most recent, National Climate Assessment, production of the Fourth National Climate Assessment (NCA4) is now underway and is expected for release in late 2018. Recent efforts are laying the foundation for a robust, inclusive assessment process that responds to information needs across the country:

• Author teams are in place. Each chapter of NCA4 is being led by a Federal Coordinating Lead Author and a Chapter Lead working with a collection of specialized expert authors. Author teams include experts from state and local governments, nonprofit organizations, academia, Federal agencies, tribal communities, and the private sector. 

• The Climate Science Special Report (CSSR), a comprehensive assessment of the state of knowledge on human-induced climate change, forms the scientific foundation for NCA4. It includes updates on observed and future projected changes in temperatures, precipitation patterns, extreme-weather events, sea-level rise, and ocean acidification, focused primarily on the United States. In addition to these more traditional climate science topics, the CSSR introduces a new “Potential Surprises” chapter. CSSR is scheduled for release in Fall 2017. Another technical scientific input, the Second State of the Carbon Cycle Report, is anticipated for late 2017. 
• State climate summaries of observed and projected climate change were recently released by NOAA, providing regionally-tailored information that will serve as a resource for the sectoral and regional analyses within NCA4, as well as for state and local decision makers.                                      
• Regional engagement with stakeholders across the country is a cornerstone of NCA’s production. NCA4 covers ten regions of the United States, with regional chapters led by non-Federal experts with strong connections in each region. To inform the development of these chapters, regional workshops seeking input from local stakeholders will be held throughout the country through March 2017.
• Sectoral and Response chapters will address climate impacts on agriculture, water resources, human health, energy, transportation, and other sectors, and response actions. Fifteen sectoral chapters will draw on regional information to provide a brief national overview of each topic. In addition, a Response section of the report will focus on adaptation and the reduction in risk that can be realized with mitigation action.

• New chapters! In response to public feedback, NCA4 will – for the first time – include chapters on air quality, international effects, the interplay of impacts across sectors and compounding stressors, the U.S. Caribbean, and both the Northern and Southern Great Plains. 

• Chapter outline reviews for regional and sectoral chapters are currently underway by the NCA Federal Steering Committee, composed of representatives from USGCRP member agencies, and the Subcommittee on Global Change Research, through February 7. 


A critical component of NCA4 success is a robust, inclusive, and transparent pub­lic review process. NCA4 is slated to be released for public comment in the fall of 2017, but look for other opportunities to contribute along the way at globalchange.gov/notices.

This December 2016 post from the White House Office of Science and Technology Policy provides earlier updates on NCA4 development.