New: National Academy of Sciences Review of the Draft 2nd State of the Carbon Cycle Report and Draft 4th National Climate Assesssment

March 12, 2018
Washington D.C.

*Cross-posted from U.S. National Academy of Sciences (NAS) communications*


Two reports reviewing major climate assessment reports have been released today by the NAS Board on Atmospheric Sciences and Climate.

Review of the Draft Fourth National Climate Assessment

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This review evaluates the draft Fourth National Climate Assessment (NCA4) developed by the U.S. Global Change Research Program (USGCRP).  The USGCRP is mandated by Congress to issue a national climate assessment every four years to evaluate the state of climate science and the broad range of impacts of climate change in the United States. 
The review concludes that the draft NCA4 report accurately describes the science of climate change and impacts occurring and likely to occur this century across the nation and, with appropriate revisions, can serve as a valuable resource for a wide range of audiences. However, improved communications of key aspects of the draft report would enhance its ability to reach broad audiences.  This includes providing more examples that describe the actions taken by private sector, public-private partnerships, and government to illustrate the range of solution-oriented efforts to address climate change impacts and associated risks.

The review suggests that increased linkages across chapters would better capture the interconnected nature of many climate change impacts.  In addition, the assessment should list significant advancements made since the Third National Climate Assessment with emphasis on emerging science, impacts, and examples of new response actions.
USGCRP will use the findings of this National Academies’ review to strengthen the draft for its expected release of the finalized Fourth National Climate Assessment later this year.

Review of the Draft Second State of the Carbon Cycle Report

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This review evaluates the draft Second State of the Carbon Cycle Report (SOCCR2), a report that  feeds into the overall climate science assessment process developed by the U.S. Global Climate Research Program. The SOCCR2 assessment aims to elucidate the fundamental physical, chemical, and biological aspects of the carbon cycle and to discuss the challenges of accounting for all major carbon stocks and flows for the North American continent.  This assessment can provide an important foundation for making a wide variety of societal decisions about land use and natural resource management, climate change mitigation strategies, urban planning, and energy production and consumption. 
The review finds the draft SOCCR2 is a very informative overview of the current scientific understanding of carbon cycle dynamics across North America. Some recommendations to strengthen the draft assessment include: providing consistency in how carbon sources and sinks are described across various chapters and figures; clarifying ambiguities in the  geographic scope of the assessment; focusing key findings on describing specifically what has been learned from new research; and expanding discussion of opportunities for effective management of carbon sources and sinks.
This review will be used to strengthen the draft SOCCR2 for its final release expected later in 2018.