USGCRP Selects Scenarios for Next National Climate Assessment
USGCRP has selected a set of emissions scenarios and related climate projections to focus on for the next quadrennial report of the National Climate Assessment (NCA). These scenarios and projections will provide a consistent basis to assess the potential future impacts of climate change on social and ecological systems, as well as how those impacts may interact with policy choices.
Scenarios are descriptions (narrative or quantitative) of how future conditions might plausibly evolve under a range of policy decisions. By offering detailed examples of how different factors could change and interact, scenarios help to limit uncertainty. The information contained in scenarios is used to drive projections of future climate change.
The selection of scenarios for the next NCA provides a coherent framework for the report and related sustained assessment products. USGCRP is announcing these selections (1) to provide the research community as much lead time as possible to incorporate them in studies that may inform the next NCA report, and (2) to give user groups, including Federal agencies, an early signal of the report’s direction.
Consistent with previous NCAs, the next NCA will leverage scenarios and model output used by the Intergovernmental Panel on Climate Change (IPCC).
- Physical climate science analyses will use the full range of IPCC “representative concentration pathway” (RCP) emissions scenarios and outcomes from the Coupled Model Intercomparison Project Phase 5 (CMIP5).
- Analyses of impacts, vulnerability, and adaptation responses will be framed by RCPs 8.5 and 4.5 as [no-lexicon]high- and low-emissions scenarios, respectively.[/no-lexicon]
- Other scenarios (for example, RCP 2.6) will be included on an as-needed basis, such as in analyses of mitigation impacts.
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