Review Of The Draft Fifth National Climate Assessment

Roughly every four years, the U.S. Global Change Research Program produces a congressionally mandated assessment of global change science and the impacts, adaptation, and mitigation of climate change in the United States. The draft Fifth National Climate Assessment (NCA5), released publicly in November 2022, covers a wide range of U.S. impacts, from human health and community well-being to the built environment, businesses and economies, and ecosystems and water resources. NCA5 had the largest scale of collaboration to date in the series, with input from hundreds of experts from all levels of governments, academia, non-government organizations, the private sector, and the public. The National Academies report provides an independent, comprehensive review and makes recommendations to strengthen the accuracy, credibility, and accessibility of the draft NCA5 report. The National Academies? review of the draft NCA5 report finds that it successfully meets the requirements of the federal mandate, provides accurate information, and effectively communicates climate science to the public, decision makers, and other stakeholders. The review makes recommendations for ways the draft NCA5 report could be strengthened, including: adopting more clear and consistent structure for key messages and figures across the report; resolving inconsistencies between chapters in how terms and topics are discussed, for example the use of scenarios and projections; intentionally applying an equity and justice lens across chapters; and increasing emphasis on certain topical areas.

Climate change poses many challenges that affect society and the natural world. With these challenges, however, come opportunities to respond. By taking steps to adapt to and mitigate climate change, the risks to society and the impacts of continued climate change can be lessened. The National Climate Assessment, coordinated by the U.S. Global Change Research Program, is a mandated report intended to inform response decisions. Required to be developed every four years, these reports provide the most comprehensive and up-to-date evaluation of climate change impacts available for the United States, making them a unique and important climate change document. The draft Fourth National Climate Assessment (NCA4) report reviewed here addresses a wide range of topics of high importance to the United States and society more broadly, extending from human health and community well-being, to the built environment, to businesses and economies, to ecosystems and natural resources. This report evaluates the draft NCA4 to determine if it meets the requirements of the federal mandate, whether it provides accurate information grounded in the scientific literature, and whether it effectively communicates climate science, impacts, and responses for general audiences including the public, decision makers, and other stakeholders.

As mandated by the Global Change Research Act (GCRA), the U.S. Global Change Research Program is currently producing a "National Climate Assessment" (NCA). The NCA is a report to inform the President, the Congress, and the American people about the current state of scientific knowledge regarding climate change effects on U.S. regions and key sectors, now and in the coming decades. This document contains an evaluation of the draft NCA report, presented through consensus responses to the Panel's Task Statement questions, and through a large collection of individual Panel member comments and suggestions for specific chapters, statements, figures, etc. While focusing primarily on practical suggestions for immediately improving the current draft, the Panel also raises some broader considerations about fundamental approaches used in certain parts of the NCA report, and about the scope of USGCRP research that underlies the NCA findings. Some suggestions can be viewed as longer-term advice for future versions of NCA work. This NCA has been a significantly more ambitious effort than previous assessments, in terms of the scope of topics addressed and the breadth of public engagement processes involved. Some of the important new areas include the use of "traceable accounts," the articulation of needs for future research and a vision for an ongoing assessment process, the outreach efforts to help various stakeholders define their climate-related information needs, and the initial (though incomplete) effort to assess the current state of climate change response activities around the nation. Given the current state of the science and the scope of resources available, we believe the NCA did a reasonable job of fulfilling its charge overall. Although more needs to be done to fully meet the nation's needs for information and guidance, such needs cannot be met without an expanded research effort on the part of the USGCRP and future assessments. The Panel suggests that the NCA report would be improved by addressing the numerous specific problems and concerns and the more cross-cutting issues raised in the consensus answers to the Task Statement questions-which include, for instance, the need to: 1. provide a clear overarching framework for the report 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; 2. clearly acknowledge how climate change affects and is affected by other types of major global environmental changes and other societal developments; 3. offer an explicit discussion about the uncertainties associated with the regional model projections presented in the NCA draft; 4. take full advantage of the e-book format planned for this document through strategic use of hyperlinks among different parts of the report and other innovative approaches that help guide the experience of the NCA's diverse audiences. As the nation continues to engage with the threats, opportunities, and surprises of climate change in its many manifestations, the 2013 NCA should prove to be a valuable resource, as a summary of the state of knowledge about climate change and its implications for the American people.

The United States Global Change Research Program (USGCRP) is moving towards a sustained assessment process that allows for more fluid and consistent integration of scientific knowledge into the mandated quadrennial National Climate Assessment. As part of this process, the USGCRP is developing the Climate Science Special Report (CSSR), a technical report that details the current state-of-science relating to climate change and its physical impacts. The CSSR is intended to focus on climate change in the United States and to inform future USGCRP products. Review of the Draft Climate Science Special Report assesses whether the draft CSSR accurately presents the scientific literature in an understandable, transparent and traceable way; whether the CSSR authors handled the data, analyses, and statistical approaches in an appropriate manner; and the effectiveness of the report in conveying the information clearly for the intended audience. This report provides recommendations for how the draft CSSR could be strengthened.

The U.S. National Climate Assessment identified a number of ways in which climate change is affecting, and is likely to affect, people, infrastructure, natural resources, and ecosystems. Those impacts, in turn, are increasingly having important current and potential future consequences for human health. There is a need to probe more deeply into how climate change impacts on the environment can create environmental stressors that, in turn, are having and/or have the potential to have significant impact on human health in a number of dimensions. In response to this need, the U.S. Global Change Research Program (USGCRP) has initiated an interagency Scientific Assessment on the Impacts of Climate Change on Human Health in the United States. The Assessment is intended to inform public health authorities, other planning and policy entities, and the general public. Review of the Draft Interagency Report on the Impacts of Climate Change on Human Health in the United States evaluates the scientific basis, findings, and key messages of the USGCRP Draft Assessment. This report offers a number of overarching suggestions on how the USGCRP report authors can enhance their identification and assessment of the science and better communicate their conclusions to all of their target audiences. These recommendations this help the Assessment to play a significant role in continued efforts to examine and explore the impacts of climate change on human health.

This National Research Council (NRC) report reviews a draft of the U.S. Climate Change Science Program (CCSP) Synthesis and Assessment Product 3.3, Weather and Climate Extremes in a Changing Climate, the 3rd in a series of 21 CCSP products addressing important topics related to climate change. The NRC report finds that the draft provides a good and thorough assessment of the important issues regarding extreme events over North America and how they may change in the context of a changing climate. The continuity and cohesion among the chapters could be improved by greater coordination among the chapter authorship teams, who should also ensure that the tone and scope of the chapters are consistent with the document's Abstract and Executive Summary. The authors should strive to consolidate the sections on tropical cyclones; however, the discussion of drought and ecological impacts could be expanded. Overall, the committee finds that the scope, content, and scientific rigor of the current draft provide a solid basis for the final version of Synthesis and Assessment Product 3.3.

This book offers valuable climate policy and climate assessment lessons, depicting what it takes to build a sustained climate assessment process. It explores the third U.S. National Climate Assessment (NCA3) report as compared with previous US national climate assessments, from both a process and content perspective. The U.S. Global Change Research Program is required by law to produce a National Climate Assessment report every four years, and these reports provide a comprehensive evaluation of climate science as well as observed and projected climate impacts on a variety of sectors. As the book describes, a key contribution of the NCA3 approach is a far more deliberate interdisciplinary process, as well as an engagement strategy that brought hundreds of public and private sector stakeholders into the assessment community. Among its most important conceptual contributions was an explicit focus on building the infrastructure to conduct better assessments over time and an experimental approach to analysis of the impacts of climate on cross-sectoral systems and inter-locking and cascading effects across sectors. Readers may explore innovations such as the development of regional climatologies and projections for every region of the US, as well as the development of the Global Change Information System. The book also highlights the need for decision-makers to be part of the assessment process, in order for assessment findings to be truly useful from a decision-maker's perspective. Many lessons have been learned by the NCA3 authors that can be useful in future assessments and adaptation processes, both within the US and internationally. This book passes on such lessons and includes an evaluation of the role of state climate assessments in ongoing national assessment processes.