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.

Nearly three thousand people died in the terrorist attacks of September 11, 2001. In Lower Manhattan, on a field in Pennsylvania, and along the banks of the Potomoc, the United States suffered the single largest loss of life from an enemy attack on its soil. In November 2002 the United States Congress and President George W. Bush established by law the National Commission on Terrorist Attacks Upon the United States, also known as the 9/11 Commission. This independent, bipartisan panel was directed to examine the facts and circumstances surrounding the September 11 attacks, identify lessons learned, and provide recommendations to safeguard against future acts of terrorism. This volume is the authorized edition of the Commission's final report.

The Next Generation Air Transportation System (NextGen) is an effort begun in 2003 whose goals include improving the capacity, efficiency, and safety of the U.S. air transportation system and also enabling reduction in noise, pollution, and energy use. The Federal Aviation Administration and various stakeholders, including equipment providers, airlines, and contractors, are currently implementing both near-term and midterm capabilities of this effort. Interim Report of a Review of the Next Generation Air Transportation System Enterprise Architecture, Software, Safety, and Human Factors is part of a larger project to examine NextGen's enterprise architecture and related issues. This interim report provides an initial assessment focusing on challenges of system architecture for software-intensive systems.