Busby explains how climate change can affect security outcomes, including violent conflict and humanitarian emergencies. Through case studies from sub-Saharan Africa, the Middle East, and South Asia, the book develops a novel argument explaining why climate change leads to especially bad security outcomes in some places but not in others.

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.

Summarizes the science of climate change and impacts on the United States, for the public and policymakers.

Society today may be more vulnerable to global-scale, long-term, climate change than ever before. Even without any human influence, past records show that climate can be expected to continue to undergo considerable change over decades to centuries. Measures for adaption and mitigation will call for policy decisions based on a sound scientific foundation. Better understanding and prediction of climate variations can be achieved most efficiently through a nationally recognized "dec-cen" science plan. This book articulates the scientific issues that must be addressed to advance us efficiently toward that understanding and outlines the data collection and modeling needed.