	Introduction

Climate change is viewed as a global issue, but proposed responses generally require action at the national level. In 1992, the United States ratified the United Nations Framework Convention on Climate Change (UNFCCC) which called on industrialized countries to take the lead in reducing greenhouse gases. Over the past 16 years, a variety of voluntary and regulatory actions have been proposed or undertaken in the United States, including monitoring of utility carbon dioxide emissions, improved appliance efficiency, and incentives for developing renewable energy sources. Since then, the Bush Administration has focused U.S. climate change policy on voluntary initiatives to reduce the growth in greenhouse gas emissions. This focus was particularly evident in the Administration's 2006 Climate Action Report (CAR) submitted under the provisions of the UNFCCC. Of the roughly 50 programs summarized in the 2006 CAR, only seven were described as "regulatory." In its 2007 decision in Massachusetts v. EPA , the Supreme Court found that the Environmental Protection Agency has the authority to regulate greenhouse gas emissions from motor vehicles under the Clean Air Act. Further, in June 2008, the Senate considered legislation ( S. 3036 ) to enact an economy-wide cap-and-trade system to reduce U.S. greenhouse gas emissions. However, a cloture motion on this bill failed, and the bill was ultimately tabled. This report provides background on the evolution of U.S. climate change policy from ratification of the UNFCCC to the George W. Bush Administration's rejection of the Kyoto Protocol programs, to the present. Current major regulatory programs that monitor or reduce greenhouse gas emissions are identified, along with their estimated effect on greenhouse gas emissions. Regulatory measures that have reduced greenhouse gas emissions are a small subset of the total U.S. effort numerically, but are responsible for a proportionally larger share of greenhouse gas emission reductions. In general, these regulatory programs were established and implemented primarily for reasons other than climate change concerns. On December 19, 2007, President Bush signed the Energy Independence and Security Act of 2007 (EISA, P.L. Renewable Fuel Standard

The Energy Policy Act of 2005 established a renewable fuel standard (RFS) requiring the use of renewable fuels in gasoline. 109-58 ), with provisions directly and indirectly related to greenhouse gas emissions. 110-140 ). In addition to the above programs, EISA also requires the establishment of an Office of Climate Change and Environment in the Department of Transportation. This office will plan, coordinate, and implement research at DOT on reducing transportation-related energy use, mitigating the causes of climate change, and addressing the impacts of climate change on transportation. As indicated below ( Table 2 ), energy-related activities are responsible for about 86% of the country's greenhouse gas emissions, and 98% of its carbon dioxide emissions. While some provisions in energy laws enacted over the past 16 years have led to lower greenhouse gas emissions or addressed climate change directly, other provisions in those same laws have almost certainly resulted in higher emissions. To date, no energy law has had reducing greenhouse gas emissions as the main organizing principle. Comprehensive climate change policy directed at reducing greenhouse gas emissions should address energy supply and consumption and, thus, be integrated with energy policy. This will be a pivotal challenge to the 111 th Congress's and the incoming Administration's anticipated efforts to enact legislation to limit greenhouse gas emissions.
Climate change is viewed as a global issue, but proposed responses generally require action at the national level. In 1992, the United States ratified the United Nations Framework Convention on Climate Change (UNFCCC), which called on industrialized countries to take the lead in reducing greenhouse gases. Over the past 16 years, a variety of voluntary and regulatory actions have been proposed or undertaken in the United States, including monitoring of electric utility carbon dioxide emissions, improved appliance efficiency, and incentives for developing renewable energy sources. This report provides background on the evolution of U.S. climate change policy, from ratification of the UNFCCC to the George W. Bush Administration's 2001 rejection of the Kyoto Protocol to the present. Recent federal court decisions—most notably the Supreme Court's 2007 decision in Massachusetts v. EPA that the Environmental Protection Agency has the authority to regulate motor vehicle greenhouse gas emissions under the Clean Air Act—have raised the issue of whether EPA should directly regulate greenhouse gases. This report focuses on major regulatory programs that monitor or reduce greenhouse gas emissions, along with their estimated effect on emissions levels.
The George H. W. Bush, Clinton, and George W. Bush Administrations largely relied on voluntary initiatives to reduce the growth of greenhouse gas emissions. This focus was particularly evident in the current Administration's 2006 Climate Action Report (CAR), submitted under the provisions of the UNFCCC. Of roughly 50 programs summarized in the 2006 CAR, seven were described as "regulatory." However, this small subset of the total U.S. effort accounts for a large share of greenhouse gas emission reductions achieved over the past decade-and-a-half. In general, these efforts were established and implemented in response to concerns other than climate change, such as energy efficiency and air quality.
The Energy Policy Act of 2005 (P.L. 109-58) included provisions indirectly related to greenhouse gas emissions, such as energy efficiency and renewable energy. The Energy Independence and Security Act of 2007 (P.L. 110-140) addresses renewable energy and conservation, but also includes provisions specifically on climate change. These include a requirement for the use of renewable fuels with lower lifecycle greenhouse gas emissions than petroleum fuels, and the establishment of an Office of Climate Change and Environment in the Department of Transportation to implement research on mitigating the causes and addressing the effects of climate change on transportation. In June 2008, the Senate considered a bill (S. 3036) to establish an economy-wide cap-and-trade system to reduce greenhouse gas emissions. However, after discussion, a cloture motion on this bill failed, and the bill was tabled.
While some provisions in energy laws enacted over the past 16 years have led to lower greenhouse gas emissions or addressed climate change directly, other provisions in those same laws have almost certainly resulted in higher emissions. To date, no energy law has had reducing greenhouse gas emissions as the main organizing principle. Energy-related activities are responsible for about 86% of the country's greenhouse gas emissions, and 98% of its carbon dioxide emissions. Climate change policy directed at reducing greenhouse gas emissions must address energy supply and consumption and, thus, be integrated with energy policy. This will be a pivotal challenge to the 111th Congress's and the incoming Administration's anticipated efforts to enact legislation to limit greenhouse gas emissions.