The U.S. Climate Change Science Program (CCSP) coordinates the efforts of 13 federal agencies to understand why climate is changing, to improve predictions about how it will change in the future, and to use that information to assess impacts on human systems and ecosystems and to better support decision making. Evaluating Progress of the U.S. Climate Change Science Program is the first review of the CCSP's progress since the program was established in 2002. It lays out a method for evaluating the CCSP, and uses that method to assess the strengths and weaknesses of the entire program and to identify areas where progress has not met expectations. The committee found that the program has made good progress in documenting and understanding temperature trends and related environmental changes on a global scale, as well as in understanding the influence of human activities on these observed changes. The ability to predict future climate changes also has improved, but efforts to understand the impacts of such changes on society and analyze mitigation and adaptation strategies are still relatively immature. The program also has not met expectations in supporting decision making, studying regional impacts, and communicating with a wider group of stakeholders.

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.

This report reviews the U.S. Climate Change Science Program's new draft assessment product on characterizing and communicating uncertainty information for climate change decision making, one of 21 climate change assessment products that the program is developing to meet the requirements of the 1990 Global Change Research Act. Although the draft assessment is effective in discussing methods of characterizing uncertainty, it falls short in several ways. It is written for researchers involved in assessment efforts and will likely be of use to them, but does not address other key audiences, particularly policymakers, decision-makers, and members of the media and general public. In addition, it does not assess the full range of "best practice approaches" for characterizing, incorporating, and communicating uncertainty. These weaknesses were due in part to a change in the prospectus after the process had begun to include new target audiences and a different scope of work. It will take a substantial revision of the current draft or production of a companion document, both requiring additional authors, to address these issues.

The U.S. Climate Change Science Program (CCSP), established in 2002 to coordinate climate and global change research conducted in the United States and to support decision-making on climate-related issues, is producing twenty-one synthesis and assessment reports that address its research, observation, and decision-support needs. The first report, produced by the National Oceanic and Atmospheric Administration (NOAA) in coordination with other agencies, focuses on understanding reported differences between independently produced data sets of temperature trends for the surface through the lower stratosphere and comparing these data sets to model simulations. To ensure credibility and quality, NOAA asked the National Research Council to conduct an independent review of the report. The committee concluded that the report Temperature Trends in the Lower Atmosphere: Understanding and Reconciling Differences is a good first draft that covers an appropriate range of issues, but that it could be strengthened in a number of ways.

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.