"Human activities are yielding rising atmospheric concentrations of greenhouse gases and other gases and particulates and are also greatly altering the Earth's land cover. A scientific consensus has emerged that those activities, if allowed to continue unabated, will have extensive, highly uncertain, but potentially serious and costly impacts on regional climates and ocean conditions throughout the world. This Congressional Budget Office (CBO) paper-prepared at the request of the Chairman of the Senate Committee on Energy and Natural Resources-presents an overview of the current understanding of the impacts of climate change in the United States, emphasizing the wide range of uncertainty about the magnitude and timing of those impacts and the implications of that uncertainty for the formulation of effective policy responses. The analysis draws from numerous published sources to summarize the current state of climate science and provide a conceptual framework for addressing climate change as an economic concern. In keeping with CBO's mandate to provide objective, impartial analysis, the paper makes no recommendations."
Congressional Budget Office: http://cbo.gov