In the 110 th Congress, Members have introduced numerous bills that would directly or indirectly address climate change. This report describes and compares bills that directly address climate change, as opposed to those that primarily address other issues (e.g., energy efficiency and conservation) but could have ancillary impacts on climate. In some cases, it is difficult to draw a line between direct and indirect climate change bills, because a specific bill or action may seek to achieve multiple objectives. This report focuses on legislative actions—including comprehensive bills with individual climate change titles or sections—that explicitly address climate change issues. These bills fall into six major categories: (1) research on the causes and effects of climate change and on methods to measure and predict climate change; (2) deployment of emission-reducing technologies in the United States or other countries; (3) requirements for U.S. participation in international climate agreements; (4) investments in systems to adapt to changes in climate; (5) establishment of greenhouse gas (GHG) monitoring systems as a basis for research or for any potential reduction program; and (6) implementation of mandatory GHG emission reduction programs. These categories are not mutually exclusive, and several bills address more than one of the above categories. There has been considerable interest in climate change issues in the 110 th Congress. As of the date of this report, Members have introduced more than 100 bills that would directly address climate change issues. Congress has enacted six legislation proposals that address climate change to some degree: P.L. 110-140 : The President signed the Energy Independence and Security Act of 2007 December 19, 2007. Among other provisions, some of which indirectly address GHG emissions, this act amends the Energy Policy Act of 2005 to expand the carbon capture research and development program. It also directs the Department of the Interior to conduct a national assessment of geologic storage capacity for carbon dioxide (CO 2 ), and instructs the Department of Energy to implement a program to demonstrate technologies for the large-scale capture of CO 2 from industrial sources of CO 2 . In addition, the act establishes within the Department of Transportation an Office of Climate Change and the Environment to coordinate research and implement strategies to address transportation issues associated with climate change. P.L. 110-161 : The President signed the Consolidated Appropriations Act of 2008 into law December 26, 2007. Among other provisions, this statute directs EPA to promulgate regulations that require mandatory reporting of GHG emissions "above appropriate thresholds in all sectors of the economy." The act directs EPA to develop the proposed rule by September 2008 and the final rule by June 2009. In addition, the act instructs NOAA to work with the National Academy of Sciences to establish a Climate Change Study Committee that will study climate change issues and make recommendations regarding climate change mitigation strategies. P.L. 110-181 : On January 28, 2008, the President signed the National Defense Authorization Act for Fiscal Year 2008. In addition to many non-climate related provisions, the act directs the Department of Defense to assess the risks of projected climate change to the department's facilities, capabilities, and missions. P.L. 110-229 : On May 8, 2008, the President signed the Consolidated Natural Resources Act of 2008. Among other provisions, the act requires the Secretary of Energy, when reviewing research and development activities for possible inclusion in the steel research and development initiative, to expand the plan in order to consider among steel project priorities the development of technologies that reduce GHG emissions. P.L. 110-246 : On June 18, 2008, Congress enacted (overriding the President's veto) the Food, Conservation, and Energy Act. Among many other provisions, the act (Section 2709) directs the Department of Agriculture (USDA) to establish technical guidelines to "measure the environmental services benefits from conservation and land management activities in order to facilitate the participation of farmers, ranchers, and forest landowners in emerging environmental services markets." USDA is to give priority to carbon markets. P.L. 110-343 : On October 3, 2008, the President signed the Emergency Economic Stabilization Act of 2008. Among many other provisions, the legislation provides a tax credit for select (geologic) carbon sequestration activities. In addition, the act directs the Department of Treasury to enter into an agreement with the National Academy of Sciences (NAS) to "undertake a comprehensive review of the Internal Revenue Code of 1986 to identify the types of and specific tax provisions that have the largest effects on carbon and other greenhouse gas emissions and to estimate the magnitude of those effects." NAS is to report its findings to Congress by October 3, 2010. In addition to enacted legislation, the House and Senate have passed several bills. Numerous bills have been reported out of committees. These bills address a range of climate change topics. These topics are discussed briefly below. Appendix A categorizes the bills and enacted legislation by the topics discussed below. Appendix B provides a brief summary of each bill's provisions and status in the legislative process. Global climate change is a complex issue. While most scientists agree that the climate is changing in response to GHG emissions, uncertainties concerning the causes and effects of climate change remain and are a continuing subject of extensive scientific research. These uncertainties include the potential effects on natural systems, as well as effects on social and political systems. Further, research is ongoing regarding technologies that improve efficiency, reduce fossil fuel consumption, and capture and store carbon dioxide (CO 2 ) emissions. One approach to addressing climate change is to promote the deployment and diffusion of technologies to reduce GHG emissions, such as carbon capture and storage (or sequestration). Within the legislative proposals, there are different methods of promoting technology deployment. One deployment strategy may involve tax incentives for investment in technologies to improve efficiency and/or lower emissions. Other deployment strategies would provide grants, loans, and other incentives for technology transfer to developing countries. In the 110 th Congress, some bills deal solely with technology deployment through tax incentives for lower-carbon technology or grants to develop and deploy carbon capture and sequestration, or through requirements that the federal government use technology with lower emissions. Other bills that create mandatory GHG reduction programs also include technology deployment as one component. The United States ratified the United Nations Framework Convention on Climate Change (UNFCCC) in 1992. Five years later, the United States signed the convention's Kyoto Protocol, but it was never submitted to the Senate for ratification. In 2001, President George W. Bush rejected the Kyoto Protocol and withdrew the United States from subsequent negotiations. Since that time, the United States has entered into other cooperative agreements, including the Asia-Pacific Partnership on Clean Development and Climate. This partnership focuses on voluntary action by member states to promote cleaner technology and related goals. However, U.S. participation in discussions over binding agreements has been limited. Some critics of GHG regulation argue that the effects on global GHG concentrations—and consequently the effects on climate—from any reduction scheme will be limited. Some therefore contend that investment should focus on preparing communities and systems to adapt to the effects of a changing climate. This notion is shared by some proponents of GHG regulation, who argue that because of earlier greenhouse gas emissions, some level of warming will occur regardless of mitigation activity. Those stakeholders support adaptation initiatives in concert with mitigation efforts. Pursuant to the UNFCCC, the United States publishes annual reports on its GHG emissions. The U.S. Environmental Protection Agency (EPA) reports this information using various techniques (e.g., fuel analysis for CO 2 ). The 2005 emissions estimates indicate that the three dominant sources of GHG emissions are electricity generation (33%), transportation (28%), and industry (19%). At the national level, the 1990 Clean Air Act requires most electric utilities to report their GHG emissions, but there is no overall national GHG reporting requirement. However, some states also gather data through voluntary registries or mandatory GHG emissions reporting mechanisms. The United States has no federal GHG reduction requirements, although there have been proposals to require such reductions. These proposals include "command and control" regulations and market-based techniques to limit emissions. Market-based programs typically take as their model the Clean Air Act's acid rain program, which employs a cap-and-trade design to control several air pollutants. Cap-and-trade systems set strict limits on specific emissions from a particular group of sources. Sources may reduce their own emissions or purchase credits (i.e., trade) from other sources that have reduced emissions below their individual allotment. This flexibility in who makes reductions can lead to lower costs. In an efficient market, entities that face relatively low emission-reduction costs would have an incentive to achieve extra emission reductions, because these additional reductions could be sold to entities that face higher emission-reduction costs. An entity facing higher costs could purchase allowances that would allow it to emit more than its initial emissions allotment. Total U.S. emissions may decrease or increase, depending on the entities covered, the GHGs controlled, and the emissions trading schemes. In the 110 th Congress, some bills cover just the electric utility sector, while others cover most or all emissions throughout the economy. Another market-based option is to establish a "carbon tax"—a direct tax on GHG emissions or on the fuels that generate emissions when combusted. To the extent that emissions reductions can be achieved at costs lower than the tax rate, those reductions will be undertaken; if emissions reductions are more expensive, covered entities would opt to pay the tax. In this way, there is an upper limit to the cost of the control program. Members have introduced several bills in the 110 th Congress that would control emissions from only the electric utility sector. The rationale for such a policy is that electricity generation emits the highest percentage of GHGs by sector, and the number of covered sources would be relatively small compared to other sectors (e.g., transportation). Moreover, power plants have experience with reporting (if not reducing) their CO 2 emissions under the Clean Air Act. Sector-specific bills generally fall into two categories: (1) bills that would control only GHGs and (2) bills that would control both GHGs and other pollutants such as mercury, sulfur dioxide, and nitrogen oxides. This latter category of bills is generally referred to as "multi-pollutant" legislation. A broader approach is to require emission reductions from multiple economic sectors. Several bills in the 110 th Congress would apply to most or all U.S. GHG emissions. These bills are often described as an "economy-wide" GHG reduction approach. These bills vary in their coverage: some bills cover the most high-emitting sectors (e.g., electricity generation, industry, and transportation) while excluding other sectors (e.g., residential and commercial); other bills grant EPA broad authority to establish regulations to reduce the most emissions at the lowest cost. Appendix A. Major Focus Areas of Climate Change Bills and Enacted Legislation in the 110 th Congress Appendix B. Key Provisions of Climate Change Legislation in the 110 th  Congress

Summary: Congressional interest in climate change legislation has grown in recent years. In the 110th Congress, Members have introduced numerous bills that directly address various aspects of climate change. These bills cover a wide spectrum, ranging from climate change research to comprehensive greenhouse gas (GHG) emissions cap-and-trade programs. As of the date of this report, Congress has enacted six broader pieces of legislation that—among many other non-climate-related provisions—address climate change in some fashion: P.L. 110-140 expands the carbon capture research and development program, requires a national assessment of geologic storage capacity for CO2, and supports technologies for the large-scale capture of CO2 from industrial sources. The act also establishes an Office of Climate Change and the Environment to coordinate research and implement strategies to address climate change-related transportation issues. P.L. 110-161 directs the Environmental Protection Agency (EPA) to develop regulations that establish a mandatory GHG reporting program that applies "above appropriate thresholds in all sectors of the economy." P.L. 110-181 directs the Department of Defense (DOD) to assess the risks of projected climate change to the department's facilities, capabilities, and missions. P.L. 110-229 requires the Secretary of Energy, when reviewing research and development activities for possible inclusion in the steel research and development initiative, to expand the plan in order to consider among steel project priorities the development of technologies that reduce GHG emissions. P.L. 110-246 directs the Department of Agriculture (USDA) to establish technical guidelines to "measure the environmental services benefits from conservation and land management activities in order to facilitate the participation of farmers, ranchers, and forest landowners in emerging environmental services markets." USDA is to give priority to carbon markets. P.L. 110-343 provides a tax credit for select (geologic) carbon sequestration activities. In addition, the National Academy of Sciences (NAS) is "to identify the types of and specific tax provisions that have the largest effects on carbon and other greenhouse gas emissions and to estimate the magnitude of those effects." NAS is to report its findings to Congress by October 3, 2010. This report briefly discusses the basic concepts on which climate change bills are based, and compares major provisions of the bills in each of the following categories: climate change research; emissions reduction technologies; U.S. actions pursuant to international emission reduction agreements; adaptation to the effects of climate change; GHG reporting and registration; and GHG emissions reduction programs.