Reflections on preparing regional chapters for NCA5

Regional chapters in the National Climate Assessment (NCA) report provide a comprehensive synthesis of how climate change is impacting United States regions and are extensively used to support climate change decision-making by local communities and policymakers. The regional chapter author teams are tasked with assessing the climate trends, risks, and responses across a range of sectors and across a vast and diverse geography, while making content locally relevant. Regional chapters have evolved in many ways since the third NCA (NCA3), often shifting from focusing on climate stressors and hazards to addressing more diverse human-centric impacts (e.g., human health), inequities, and other barriers to action. The fifth NCA (NCA5) author teams were constructed to be intentionally diverse, including more social scientists and cultural practitioners. Here, regional chapter authors provide reflections on the assessment process and identify some best practices for developing an effective regional chapter. These include building a diverse and complementary author team, utilizing technical contributors to enhance the technical and geographical expertise of the team, and conducting extensive public engagement with local communities and policymakers throughout the process. To improve future regional NCA chapters, we identify several recommendations: (1) thoughtful analysis and possible revision of regional boundaries, (2) inclusion of authors from underrepresented regions on national-scale topic chapters, (3) structured cross-chapter engagement among regional chapters, (4) a holistic communications plan for the post-release period, and (5) better coordination with sub-national climate assessments.