As the scientific evidence of climate change has mounted, so has congressional activity. The number of climate change-related legislative proposals increased from seven introduced in the 105th Congress (1997-1998) to 25 in the 106th Congress (1999-2000), to over 80 in the 107th Congress (2001-2002) to 96 in the 108th Congress (2003-2004). During the 109th Congress (2005-2006), 106 bills, resolutions, and amendments specifically addressing global climate change and greenhouse gas (GHG) emissions were introduced. In addition, provisions of the enacted Energy Policy Act of 2005, though they do not refer to climate change or GHG emissions specifically, were relevant to climate change.
Climate change measures are increasingly being offered by members of both the Democratic and Republican Parties (to which nearly all members of Congress belong). During debate over the Energy Policy Act of 2005, in particular, the Senate voted on four climate change amendments, two of which passed – including a nonbinding resolution expressing the sense of the Senate that human-caused GHGs are causing temperatures to rise, and that Congress should enact a national mandatory, market-based program to slow, stop, and reverse the growth of these emissions – and one of which was enacted into law. The growing interest suggests that a bipartisan consensus is developing around the need to address climate change. Addressing climate change will ultimately require a comprehensive set of approaches, including a mandatory program to reduce GHG emissions (such as a program to cap GHG emissions and allow trading of emission credits), and efficiency standards to promote the use of efficient products and technologies (See The Agenda for Climate Action ).