Scenarios and US National Climate Assessments: Where have they been and where could they go?

Abstract:

U.S. National Climate Assessments (NCA), conducted under the auspices of the U.S. Global Change Research Program, analyze the effects of global change on the United States and examine current and projected changes out to 100 years. Scenarios of global change have been incorporated in all NCAs to date, although such scenarios have typically been developed late in the assessment cycle, limiting the depth of their use in regional and sectoral assessments. This lack of use is particularly notable for scenarios focused on aspects other than climate and associated projections of temperature and precipitation. Here, we review how scenarios have been incorporated in previous NCAs and present potential options for both the development and inclusion of a wider range of scenarios topics in future quadrennial NCA reports and other sustained assessment activities within USGCRP and federal agencies. Incorporating a broad range of U.S. scenarios will present both intellectual and programmatic challenges, as scenario developers from relatively disparate communities will need to come together to create internally consistent assumptions within each type of scenario (e.g. climate, land cover and land use, population) for sub-national scales. As USGCRP moves forward with a sustained assessment process, a richer set of scenarios can serve as a bridge between the research community, decision makers, and practitioners.