Expert Report

A Review of the Draft 2013 National Climate Assessment (2013)

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Mandated by the Global Change Research Act, the National Climate Assessment is produced every four years by the U.S. Global Change Research Program. This NRC report evaluates the draft 2013 National Climate Assessment. It provides both practical suggestions for immediate improvements to the document, and broader considerations, for example, about fundamental approaches used in certain parts of the draft Assessment, and about the scope of the research that underlies the Assessment findings. Overall, the Panel finds that given the current state of the science and the scope of resources available, the 2013 National Climate Assessment does a reasonable job of fulfilling its charge to inform the President, the Congress, and the nation about the current state of scientific knowledge regarding climate change effects.

Key Messages

  • The draft National Climate Assessment does generally meet the requirements of the legislative mandate in terms of timeliness, in summarizing key findings of U.S. Global Change Research Program research, in analyzing effects on the various sectors/systems specified in the Global Change Research Act, and in projecting trends for the coming decades.
  • The National Climate Assessment has gone beyond the explicit Global Change Research Act in a few ways, which the committee finds are worthwhile and constructive additions to the report. For instance, the draft National Climate Assessment identifies research needs and knowledge gals, provides a vision for an ongoing assessment process, and examines mitigation and adaptation responses.
  • The National Climate Assessment would be improved by providing a more clear, overarching framework that helps readers understand climate change as part of a complex system with interacting physical, biological, and human social/economic dimensions, and offers practical guidance on using iterative risk management strategies to make decisions in the face of large uncertainties.
  • There is a need for the National Climate Assessment to more clearly acknowledge how climate change affects and is affected by other types of major global environmental changes and other societal developments.
  • The National Climate Assessment would be improved by offering a more explicit discussion about the uncertainties associated with the regional model projections presented in the draft.
  • Making full use of the e-book format planned for the National Climate Assessment—for example through the strategic use of hyperlinks among different parts of the Assessment—would help guide the experience of the Assessment's diverse audiences.