I. Introduction
The United States Global Change Research Program (USGCRP) is overseeing the production of a technical report that details the current state of science relating to climate change and its physical manifestations. The draft Climate Science Special Report (CSSR) is intended to serve as technical input to the Fourth National Climate Assessment (NCA4), providing an updated detailed analysis of the findings of how climate change is affecting the weather and climate across the United States and its territories, and reporting information and climate projections that can inform NCA4 analyses. The Executive Summary (ES) within the draft CSSR will also provide the basis for a NCA4 chapter summarizing the physical science basis for climate change. This draft report is designated as a Highly Influential Scientific Assessment (HISA).
The National Academies of Sciences, Engineering, and Medicine have a history of convening expert groups to provide independent review of USGCRP assessment reports and currently has a standing Committee to Advise USGCRP. The Committee to Review the Draft Climate Science Special Report (“The Committee”) was convened in December 2016 and is composed of members with diverse climate science backgrounds that span the breadth of focus topics included in the draft CSSR.
The Committee was specifically charged with addressing the following Statement of Task questions (see also Appendix B for the Statement of Task):
- Are the goals, objectives, and intended audience of the product clearly described in the document? Does the report meet its stated goals?
- Does the report accurately reflect the scientific literature? Are there any critical content areas missing from the report?
- Are the findings documented in a consistent, transparent, and credible way?
- Are the report’s key messages and graphics clear and appropriate? Specifically, do they reflect supporting evidence, include an assessment of likelihood, and communicate effectively?
- Are the data and analyses handled in a competent manner? Are statistical methods applied appropriately?
- Are the document’s presentation, level of technicality, and organization effective?
- What other significant improvements, if any, might be made in the document?
The Committee had an opportunity to discuss the draft CSSR with the report’s authors and USGCRP staff during a WebEx briefing on December 8, 2016 and reviewed the draft report concurrent with the public comment period. The Committee met in person in Washington, DC on January 9-10, 2017 to discuss the draft CSSR and had follow up discussions to reach a consensus on the Committee’s responses to the Statement of Task questions. Reviews of individual draft CSSR chapters were conducted by small teams of committee members with the appropriate expertise, who then led the discussion of their comments with the full committee. The Committee reviewed the entire draft CSSR including figures, tables, and traceable accounts. This National Academies report provides a synthesis of overall recommendations and comments specific to the ES and individual chapters. A collection of line comments is also provided in Appendix A. Key findings presented in the draft CSSR that the Committee had specific comments for have been copied into this document to provide context. As is the nature of these sorts of reviews, many of the comments recommend ways to improve the draft CSSR and the Committee offers these suggestions in the spirit of constructive criticism.
