This book recommends the initiation of an "integrated" research program to study the role of aerosols in the predicted global climate change. Current understanding suggest that, even now, aerosols, primarily from anthropogenic sources, may be reducing the rate of warming caused by greenhouse gas emissions. In addition to specific research recommendations, this book forcefully argues for two kinds of research program integration: integration of the individual laboratory, field, and theoretical research activities and an integrated management structure that involves all of the concerned federal agencies.

This book recommends the initiation of an "integrated" research program to study the role of aerosols in the predicted global climate change. Current understanding suggest that, even now, aerosols, primarily from anthropogenic sources, may be reducing the rate of warming caused by greenhouse gas emissions. In addition to specific research recommendations, this book forcefully argues for two kinds of research program integration: integration of the individual laboratory, field, and theoretical research activities and an integrated management structure that involves all of the concerned federal agencies.

This book recommends the initiation of an "integrated" research program to study the role of aerosols in the predicted global climate change. Current understanding suggest that, even now, aerosols, primarily from anthropogenic sources, may be reducing the rate of warming caused by greenhouse gas emissions. In addition to specific research recommendations, this book forcefully argues for two kinds of research program integration: integration of the individual laboratory, field, and theoretical research activities and an integrated management structure that involves all of the concerned federal agencies.

The Climate Change Science Program (CCSP) and its predecessor U.S. Global Change Research Program have sponsored climate research and observations for nearly 15 years, yet the overall progress of the program has not been measured systematically. Metricsâ€"a system of measurement that includes the item being measured, the unit of measurement, and the value of the unitâ€"offer a tool for measuring such progress; improving program performance; and demonstrating program successes to Congress, the Office of Management and Budget, and the public. This report lays out a framework for creating and implementing metrics for the CCSP. A general set of metrics provides a starting point for identifying the most important measures, and the principles provide guidance for refining the metrics and avoiding unintended consequences.

The growing problem of changing environmental conditions caused by climate destabilization is well recognized as one of the defining issues of our time. The root problem is greenhouse gas emissions, and the fundamental solution is curbing those emissions. Climate geoengineering has often been considered to be a "last-ditch" response to climate change, to be used only if climate change damage should produce extreme hardship. Although the likelihood of eventually needing to resort to these efforts grows with every year of inaction on emissions control, there is a lack of information on these ways of potentially intervening in the climate system. As one of a two-book report, this volume of Climate Intervention discusses albedo modification - changing the fraction of incoming solar radiation that reaches the surface. This approach would deliberately modify the energy budget of Earth to produce a cooling designed to compensate for some of the effects of warming associated with greenhouse gas increases. The prospect of large-scale albedo modification raises political and governance issues at national and global levels, as well as ethical concerns. Climate Intervention: Reflecting Sunlight to Cool Earth discusses some of the social, political, and legal issues surrounding these proposed techniques. It is far easier to modify Earth's albedo than to determine whether it should be done or what the consequences might be of such an action. One serious concern is that such an action could be unilaterally undertaken by a small nation or smaller entity for its own benefit without international sanction and regardless of international consequences. Transparency in discussing this subject is critical. In the spirit of that transparency, Climate Intervention: Reflecting Sunlight to Cool Earth was based on peer-reviewed literature and the judgments of the authoring committee; no new research was done as part of this study and all data and information used are from entirely open sources. By helping to bring light to this topic area, this book will help leaders to be far more knowledgeable about the consequences of albedo modification approaches before they face a decision whether or not to use them.

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.

This Synthesis and Assessment Product (SAP) critically reviews current knowledge about global distributions and properties of atmospheric aerosols, as they relate to aerosol impacts on climate. It assesses possible next steps aimed at substantially reducing uncertainties in aerosol radiative forcing estimates. Current measurement techniques and modeling approaches are summarized, providing context. The objectives of this report are: (1) to promote a consensus about the knowledge base for climate change decision support; and (2) to provide a synthesis and integration of the current knowledge of the climate-relevant impacts of anthropogenic aerosols. Illustrations.