Development of NCA5 continued throughout 2021, with many important milestones. NCA5 builds on the lessons learned from previous assessments, while aiming to enhance the diversity of its authors and contributors, address emerging priority topics, and enhance public engagement processes. In the spring and summer of 2021, the NCA5 Federal Steering Committee selected the report’s federal coordinating leads and chapter leads. Chapter leadership then selected a diverse group of expert contributors—nearly 500 authors and 200 technical contributors—representing all 50 states, Puerto Rico, the U.S. Virgin Islands, Guam, and Palau.

In response to federal and public feedback received since the publication of NCA4, NCA5 added two new chapters (Economics; Social Systems and Justice) and a climate indicators appendix that highlights key physical, ecological, and social systems data used to track trends and impacts related to our changing climate. Several members of USGCRP’s Indicators Interagency Working Group—which focuses primarily on leveraging existing federal indicators efforts to support USGCRP’s assessment activities—are serving as authors on the appendix. NCA5 will also include five new sections focused on cross-cutting topics: wildfire in the western United States, COVID-19, risks to supply chains, compound extreme events, and blue carbon.

In Fall 2021, USGCRP hosted the first chapter leadership and all-author meetings to provide training for around 500 authors on foundational NCA topics, including author roles and responsibilities, legal guidelines, source material requirements, timeline, figure development, and documentation. A key element of this training included discussion of themes that cut across chapter topics, such as environmental justice and Indigenous Knowledge and perspectives. Following orientation, author teams developed annotated outlines, which USGCRP member agencies reviewed prior to release for public comment.

Building on the successful public engagement efforts of NCA4, NCA5 planned a new public comment opportunity and 34 online public engagement workshops. Largely organized in 2021, these engagement efforts gathered feedback on chapter outlines and informed the author teams’ approach early in the writing process.