This report reviews threshold changes in North American

Climate change, interacting with changes in land use and demographics, will affect important human dimensions in the United States, especially those related to human health, settlements and welfare.

Human-induced climate change is a major and growing concern to U.S. policymakers and citizens who need the best available science to inform their decisions. This report responds to that need by synthesizing the large and growing body of science that deals with how climate is changing, and the impacts of these changes on the United States, now and in the future.

Changes in extreme weather and climate events have significant impacts and are among the most serious challenges to society in coping with a changing climate. This report provides current assessments of climate change science to inform public debate, policy, and operational decisions.

Climate affects the design, construction, safety, operations, and maintenance of transportation infrastructure and systems. The prospect of a changing climate raises critical questions regarding how alterations in temperature, precipitation, storm events, and other aspects of the climate could affect the nation's roads, airports, rail, transit systems, pipelines, ports, and waterways. Phase I of this regional assessment of climate change and its potential impacts on transportation systems addresses these questions for the region of the U.S.