Global climate change is one of America's most significant long-term policy challenges. Human activity-especially the use of fossil fuels, industrial processes,

Climate change is occurring. It is very likely caused by the emission of greenhouse gases from human activities, and poses significant risks for a range of huma

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 huma

Everyone-government agencies, private organizations, and individuals-is facing a changing climate: an environment in which it is no longer prudent to follow rou