Navigating complex waters: Designing a process for the development of the National Climate Assessment

Scientific assessments are tools used to look across a broad body of knowledge and draw overarching conclusions about the state of the science. They allow experts to synthesize technical knowledge and develop broad understanding of observed and future trends, risks, and opportunities. The National Climate Assessment (NCA), a major climate report of the United States (U.S.) Government, is one such assessment report. The NCA was created by Congressional statute and is classified as a Highly Influential Scientific Assessment, which results in a wide range of obligations, as well as required compliance with various statutes and other federal policies and procedures. The NCA also represents a unique effort to bring together federal agencies, the scientific community, and users of climate science throughout the U.S. to empower decision-making, build consensus, and drive climate actions. Innovations in the NCA development process over multiple cycles of the report’s development were implemented to meet both evolving legal requirements and user needs are described in this paper to share institutional knowledge and best practices with those assessment developers who might be navigating similarly complex constraints. This paper seeks to summarize that history and draw out some valuable lessons for future interagency assessment development teams. A discussion of critical innovations, including expansion of technical resources, knowledge bases, and communication tools, is included to inform the development process of future scientific assessments.