	Introduction

The U.S. Fourth National Climate Assessment, released in 2018, concluded that "the impacts of global climate change are already being felt in the United States and are projected to intensify in the future—but the severity of future impacts will depend largely on actions taken to reduce greenhouse g as [GHG] emissions and to adapt to the changes that will occur." Their views regarding climate change cover a wide range of perspectives. If Congress were to consider establishing a program to reduce GHG emissions, one option would be to apply a tax or fee on GHG emissions or the inputs that produce them. In the 115 th Congress, Members introduced nine carbon tax or fee proposals. On the other hand, many Members have expressed their opposition to a carbon tax. In 2018, the House passed a resolution "expressing the sense of Congress that a carbon tax would be detrimental to the United States economy" ( H.Con.Res. Rate of Carbon Tax

A central policy choice when establishing a price on GHG emissions is the rate of the carbon tax. Policymakers would face challenging decisions regarding the distribution of the new carbon tax revenues. When deciding how to allocate the new revenue stream, policymakers would likely encounter trade-offs among objectives, including:
reducing the economy-wide costs resulting from a carbon tax program; alleviating the costs borne by subgroups in the U.S. population, particularly low-income households and/or communities most dependent on carbon-intensive economic activity; and supporting specific policy objectives, such as domestic employment, climate change adaptation, energy efficiency, technological advance, energy diversity, or federal deficit reduction, among others. Ultimately, the economy-wide effects would depend on a number of factors, including, but not limited to, the magnitude and scope of the carbon tax and, most importantly, use of the ensuing revenues. Some studies cite particular economic modeling scenarios in which a carbon tax with certain revenue recycling applications would produce a net increase in GDP or economic welfare compared to a baseline scenario. Some may point out that the GDP impact estimates do not account for the environmental and public health benefits for reducing GHG emissions and that the GDP projections should be compared with the climate benefits achieved from the program as well as the estimated costs of taking no action. Additional Considerations

		Impacts on GHG Emission Levels

Multiple economic studies have estimated the emission reductions that particular carbon tax designs could achieve. The 2018 Stanford Energy Modeling Forum study ("EMF 32") assembled 11 modeling teams to analyze the economic impacts of four carbon tax scenarios starting in 2020: a $25/metric ton and $50/metric ton carbon tax, increasing annually by 1% and 5%. Based on these results, the study authors concluded that each of the tax rate scenarios would likely achieve the U.S. CO 2 emission reduction targets under the Paris Agreement. A carbon tax would generate a new revenue stream. A 2018 CBO study estimated that a $25/metric ton tax on CO 2 emissions from energy-related activities and other selected GHG emission sources would yield approximately $100 billion in the first year of the program. To put this estimate in context, the CBO projected that total federal revenue would be $3.5 trillion in FY2019. The central trade-offs involve minimizing economy-wide costs, lessening the costs borne by specific groups—particularly low-income households—and supporting a range of specific policy objectives. In general, economic literature finds that some of the modeled revenue applications would reduce the economy-wide costs imposed by a carbon tax but may not eliminate them entirely. These scenarios involve using carbon tax revenues to offset reductions in existing, distortionary taxes, such as corporate income or payroll taxes. Although the models indicate that these revenue applications would yield the greatest benefit to the economy overall, the models also find that lower-income households would likely face a disproportionate impact under such revenue applications. As lower-income households spend a greater proportion of their income on energy needs, these households are expected to experience disproportionate impacts from a carbon tax if revenues were not recycled back to them in some fashion, such as a lump-sum distribution. An additional concern with a carbon tax involves potential disproportionate impacts to "emission-intensive, trade-exposed industries." Policymakers could select among several options to address these concerns, either by establishing a border carbon adjustment program or allocating some of the carbon tax revenues to selected industry sectors based on an output-based metric. Relatedly, a carbon tax is projected to disproportionately impact fossil fuel industries, particularly coal, and the communities that rely on their employment. To alleviate these impacts, policymakers could allocate some of the carbon tax revenue to provide transition assistance to employees or affected communities.
The U.S. Fourth National Climate Assessment, released in 2018, concluded that "the impacts of global climate change are already being felt in the United States and are projected to intensify in the future—but the severity of future impacts will depend largely on actions taken to reduce greenhouse gas [GHG] emissions and to adapt to the changes that will occur." Members of Congress and stakeholders articulate a wide range of perspectives over what to do, if anything, about GHG emissions, future climate change, and related impacts. If Congress were to consider establishing a program to reduce GHG emissions, one option would be to attach a price to GHG emissions with a carbon tax or GHG emissions fee. In the 115th Congress, Members introduced nine bills to establish a carbon tax or emissions fee program. However, many Members have expressed their opposition to such an approach. In particular, in the 115th Congress, the House passed a resolution "expressing the sense of Congress that a carbon tax would be detrimental to the United States economy."
Multiple economic studies have estimated the emission reductions that particular carbon tax would achieve. For example, a 2018 study analyzed various impacts of four carbon tax rate scenarios: a $25/metric ton of CO2 and $50/metric ton of CO2 carbon tax, increasing annually by 1% and 5%. The study concluded that each of the scenarios would likely achieve the U.S. GHG emission reduction target pledged under the international Paris Agreement (at least in terms of CO2 emissions).
A carbon tax system would generate a new revenue stream, the magnitude of which would depend on the scope and rate of the tax, among other factors. In 2018, the Congressional Budget Office (CBO) estimated that a $25/metric ton carbon tax would yield approximately $100 billion in its first year. CBO projected that federal revenue would total $3.5 trillion in FY2019.
Policymakers would face challenging decisions regarding the distribution of the new carbon tax revenues. Congress could apply revenues to support a range of policy objectives but would encounter trade-offs among the objectives. The central trade-offs involve minimizing economy-wide costs, lessening the costs borne by specific groups—particularly low-income households and displaced workers in certain industries (e.g., coal mining)—and supporting other policy objectives.
A primary argument against a carbon tax regards it potential economy-wide impacts, often measured as impacts to the U.S. gross domestic product (GDP). Some may argue that projected impacts should be compared with the climate benefits achieved from the program as well as the estimated costs of taking no action. The potential impacts would depend on a number of factors, including the program's magnitude and design and, most importantly, the use of carbon tax revenues.
In general, economic literature finds that some of the revenue applications would reduce the economy-wide costs from a carbon tax but may not eliminate them entirely. In addition, some studies cite particular economic modeling scenarios in which certain carbon tax revenue applications produce a net increase in GDP compared to a baseline scenario. These scenarios involve using carbon tax revenues to offset reductions in other tax rates (e.g., corporate income or payroll taxes). Although economic models generally indicate that these particular revenue applications would yield the greatest benefit to the economy overall, the models also find that lower-income households would likely face a disproportionate impact under such an approach. As lower-income households spend a greater proportion of their income on energy needs (electricity, gasoline), these households are expected to experience disproportionate impacts from a carbon tax if revenues were not recycled back to them in some fashion (e.g., lump-sum distribution).
A price on GHG emissions could create a competitive disadvantage for some industries, particularly "emission-intensive, trade-exposed industries." Policymakers have several options to address this concern, including establishing a "border carbon adjustment" program, which would levy a fee on imports from countries without comparable GHG reduction programs. Alternatively, policymakers could allocate (indefinitely or for a period of time) some of the carbon tax revenues to selected industry sectors or businesses. Relatedly, a carbon tax system is projected to disproportionately impact fossil fuel industries, particularly coal, and the communities that rely on their employment. To alleviate these impacts, policymakers may consider using some of the revenue to provide transition assistance to employees or affected communities.