Climate change and greenhouse gas (GHG) emissions have been an issue in the 108th Congress, as they have been over the past decade. Bills directly addressing climate change issues range from those focused primarily on climate change research (H.R. 1578 and S. 1164) to comprehensive emissions cap and trading programs for all six greenhouse gases (S. 139 and H.R. 4067). This report briefly discusses basic concepts on which these bills are based, and compares major provisions of the bills in each of the following categories: climate change research, GHG reporting and registries, and cap and trade programs.