The federal government has committed several billion dollars in annual spending, mostly by the Department of Energy and NASA, on projects to expand the understanding of climate change or to reduce carbon dioxide and other greenhouse-gas (GHG) emissions. A recently released study by the Congressional Budget Office examines current spending on the efforts and presents an analysis of recent trends.
According to the CBO study appropriations for work related to climate change totaled about $99 billion (in 2009 dollars) in the 1998-2009 period. It noted that, "For most of that period, federal resources devoted to examining and mitigating climate change grew slowly and unevenly when adjusted for inflation." A summary of the study on the CBO Director's blog noted that, "During that period, the nation's commitment to climate-related technology development increased significantly, as has the forgone revenue attributable to tax preferences. Funding for climate science and international assistance, by contrast, stayed roughly constant."