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.

Climate change is occurring, is caused largely by human activities, and poses significant risks for-and in many cases is already affecting-a broad range of human and natural systems. The compelling case for these conclusions is provided in Advancing the Science of Climate Change, part of a congressionally requested suite of studies known as America's Climate Choices. While noting that there is always more to learn and that the scientific process is never closed, the book shows that hypotheses about climate change are supported by multiple lines of evidence and have stood firm in the face of serious debate and careful evaluation of alternative explanations. As decision makers respond to these risks, the nation's scientific enterprise can contribute through research that improves understanding of the causes and consequences of climate change and also is useful to decision makers at the local, regional, national, and international levels. The book identifies decisions being made in 12 sectors, ranging from agriculture to transportation, to identify decisions being made in response to climate change. Advancing the Science of Climate Change calls for a single federal entity or program to coordinate a national, multidisciplinary research effort aimed at improving both understanding and responses to climate change. Seven cross-cutting research themes are identified to support this scientific enterprise. In addition, leaders of federal climate research should redouble efforts to deploy a comprehensive climate observing system, improve climate models and other analytical tools, invest in human capital, and improve linkages between research and decisions by forming partnerships with action-oriented programs.

The past 15 years have seen marked progress in observing, understanding, and predicting weather. At the same time, the United States has failed to match or surpass progress in operational numerical weather prediction achieved by other nations and failed to realize its prediction potential; as a result, the nation is not mitigating weather impacts to the extent possible. This book represents a sense of the weather community as guided by the discussions of a Board on Atmospheric Sciences and Climate community workshop held in summer 2009. The book puts forth the committee's judgment on the most pressing high level, weather-focused research challenges and research to operations needs, and makes corresponding recommendations. The book addresses issues including observations, global non-hydrostatic coupled modeling, data assimilation, probabilistic forecasting, and quantitative precipitation and hydrologic forecasting. The book also identifies three important, emerging issues-predictions of very high impact weather, urban meteorology, and renewable energy development-not recognized or emphasized in previous studies. Cutting across all of these challenges is a set of socioeconomic issues, whose importance and emphasis-while increasing-has been undervalued and underemphasized in the past and warrants greater recognition and priority today.

The National Science Foundation's Division of Atmospheric Sciences (ATM) supports research to develop new understanding of the Earth's atmosphere and how the Sun impacts it. Strategic Guidance for the National Science Foundation's Support of the Atmospheric Sciences: An Interim Report provides preliminary guidance to ATM on its strategy for achieving its goals in the atmospheric sciences, including cutting-edge research, education, and workforce development; service to society; computational and observational objectives; and data management. The book reviews how the atmospheric sciences have evolved over the past several decades and analyzes the strengths and limitations of the various modes of support employed by ATM, such as principal investigator grants, small and large centers, and cooperative agreements to support observing or computational facilities. Based on this preliminary analysis, the book concludes that the current support reflects the current needs of the community. Given the changing research environment for the atmospheric sciences, the book recommends that ATM engage the community in the development of a strategic plan to enable determination of the appropriate balance of activities and modes of support into the future. A strategic planning process will also help ATM plan for large or long-term investments; facilitate appropriate allocation of resources to cross-disciplinary, interagency, and international research efforts; ensure that the United States will continue to be a leader in atmospheric research; and enhance the transparency of the rationale behind ATM decisions.

Climate change is occurring. It is very likely caused by the emission of greenhouse gases from human activities, and poses significant risks for a range of human and natural systems. And these emissions continue to increase, which will result in further change and greater risks. America's Climate Choices makes the case that the environmental, economic, and humanitarian risks posed by climate change indicate a pressing need for substantial action now to limit the magnitude of climate change and to prepare for adapting to its impacts. Although there is some uncertainty about future risk, acting now will reduce the risks posed by climate change and the pressure to make larger, more rapid, and potentially more expensive reductions later. Most actions taken to reduce vulnerability to climate change impacts are common sense investments that will offer protection against natural climate variations and extreme events. In addition, crucial investment decisions made now about equipment and infrastructure can "lock in" commitments to greenhouse gas emissions for decades to come. Finally, while it may be possible to scale back or reverse many responses to climate change, it is difficult or impossible to "undo" climate change, once manifested. Current efforts of local, state, and private-sector actors are important, but not likely to yield progress comparable to what could be achieved with the addition of strong federal policies that establish coherent national goals and incentives, and that promote strong U.S. engagement in international-level response efforts. The inherent complexities and uncertainties of climate change are best met by applying an iterative risk management framework and making efforts to significantly reduce greenhouse gas emissions; prepare for adapting to impacts; invest in scientific research, technology development, and information systems; and facilitate engagement between scientific and technical experts and the many types of stakeholders making America's climate choices.

Technology has propelled the atmospheric sciences from a fledgling discipline to a global enterprise. Findings in this field shape a broad spectrum of decisionsâ€"what to wear outdoors, whether aircraft should fly, how to deal with the issue of climate change, and more. This book presents a comprehensive assessment of the atmospheric sciences and offers a vision for the future and a range of recommendations for federal authorities, the scientific community, and education administrators. How does atmospheric science contribute to national well-being? In the context of this question, the panel identifies imperatives in scientific observation, recommends directions for modeling and forecasting research, and examines management issues, including the growing problem of weather data availability. Five subdisciplinesâ€"physics, chemistry, dynamics and weather forecasting, upper atmosphere and near-earth space physics, climate and climate changeâ€"and their status as the science enters the twenty-first century are examined in detail, including recommendations for research. This readable book will be of interest to public-sector policy framers and private-sector decisionmakers as well as researchers, educators, and students in the atmospheric sciences.

Our ability to observe and forecast severe weather events has improved markedly over the past few decades. Forecasts of snow and ice storms, hurricanes and storm surge, extreme heat, and other severe weather events are made with greater accuracy, geographic specificity, and lead time to allow people and communities to take appropriate protective measures. Yet hazardous weather continues to cause loss of life and result in other preventable social costs. There is growing recognition that a host of social and behavioral factors affect how we prepare for, observe, predict, respond to, and are impacted by weather hazards. For example, an individual's response to a severe weather event may depend on their understanding of the forecast, prior experience with severe weather, concerns about their other family members or property, their capacity to take the recommended protective actions, and numerous other factors. Indeed, it is these factors that can determine whether or not a potential hazard becomes an actual disaster. Thus, it is essential to bring to bear expertise in the social and behavioral sciences (SBS)â€"including disciplines such as anthropology, communication, demography, economics, geography, political science, psychology, and sociologyâ€"to understand how people's knowledge, experiences, perceptions, and attitudes shape their responses to weather risks and to understand how human cognitive and social dynamics affect the forecast process itself. Integrating Social and Behavioral Sciences Within the Weather Enterprise explores and provides guidance on the challenges of integrating social and behavioral sciences within the weather enterprise. It assesses current SBS activities, describes the potential value of improved integration of SBS and barriers that impede this integration, develops a research agenda, and identifies infrastructural and institutional arrangements for successfully pursuing SBS-weather research and the transfer of relevant findings to operational settings.

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 US Global Change Research Program (USGCRP) is a collection of 13 Federal entities charged by law to assist the United States and the world to understand, assess, predict, and respond to human-induced and natural processes of global change. As the understanding of global change has evolved over the past decades and as demand for scientific information on global change has increased, the USGCRP has increasingly focused on research that can inform decisions to cope with current climate variability and change, to reduce the magnitude of future changes, and to prepare for changes projected over coming decades. Overall, the current breadth and depth of research in these agencies is insufficient to meet the country's needs, particularly to support decision makers. This report provides a rationale for evaluating current program membership and capabilities and identifying potential new agencies and departments in the hopes that these changes will enable the program to more effectively inform the public and prepare for the future. It also offers actionable recommendations for adjustments to the methods and procedures that will allow the program to better meet its stated goals.

During the past decade, scientists have learned much about the complex natural processes that influence climate variability and change, and our ability to model climate has increased significantly. We also have begun to better identify those parts of the climate system that are particularly important and not well understood and that therefore limit our ability to project the future evolution of Earth's climate. One of these critical areas is our understanding of the role of feedbacks in the climate system and their role in determining climate sensitivity. Feedbacks are processes in the climate system that can either amplify or dampen the system's response to changed forcings. This study looks at what is known and not known about climate change feedbacks and seeks to identify the feedback processes most in need of improved understanding. It identifies key observations needed to monitor and understand climate feedbacks, discusses ways to evaluate progress in understanding climate feedbacks, recommends ways to improve climate modeling and analysis for climate feedbacks research, and identifies priority areas for research.