The 1997 Conference on the World Climate Research Programme to the Third Conference of the Parties of the United Nations Framework Convention on Climate Change concluded that the global capacity to observe the Earth's climate system is inadequate and is deteriorating worldwide. As a result, the chair of the subcommittee of the U.S. Global Change Research Program (USGCRP) requested a National Research Council study to assess the current status of the climate observing capabilities of the United States. This report focuses on existing observing systems for detection and attribution of climate change, with special emphasis on those systems with long time series.

The 1997 Conference on the World Climate Research Programme to the Third Conference of the Parties of the United Nations Framework Convention on Climate Change concluded that the global capacity to observe the Earth's climate system is inadequate and is deteriorating worldwide. As a result, the chair of the subcommittee of the U.S. Global Change Research Program (USGCRP) requested a National Research Council study to assess the current status of the climate observing capabilities of the United States. This report focuses on existing observing systems for detection and attribution of climate change, with special emphasis on those systems with long time series.

Detailed weather observations on local and regional levels are essential to a range of needs from forecasting tornadoes to making decisions that affect energy security, public health and safety, transportation, agriculture and all of our economic interests. As technological capabilities have become increasingly affordable, businesses, state and local governments, and individual weather enthusiasts have set up observing systems throughout the United States. However, because there is no national network tying many of these systems together, data collection methods are inconsistent and public accessibility is limited. This book identifies short-term and long-term goals for federal government sponsors and other public and private partners in establishing a coordinated nationwide "network of networks" of weather and climate observations.

Is the climate warming? Is the hydrological cycle intensifying? Is the climate becoming more variable or extreme? Is the chemical composition of the atmosphere changing? Is the solar irradiance constant? Answers to these questions are fundamental to understanding, predicting, and assessing climate on time scales ranging from weeks to a century. Atmospheric, oceanic, and environmental scientists have primarily relied on an ad-hoc collection of disparate environmental observational and data management systems to address these problems. But these systems were not designed to measure climate variations and, as a result, changes and variations of the earth system during the instrumental climate record is far from unequivocal. This book develops a framework from which a Global Climate Observing System, currently being discussed in international forums, can be implemented to monitor changes and variations of climate. Audience: Administrators, policy makers, professionals, graduate students, and others interested in learning how we can ensure a long-term climate record for application to national economic development and understanding ecosystem dynamics.

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.