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
The global scientific and policy community now unequivocally accepts that human activities cause global climate change. Although information on climate change i