Climate Change: Federal Mitigation and Adaptation Policies

Climate change policy addresses both mitigation (reducing greenhouse gas emissions to limit future warming) and adaptation (preparing for and responding to climate impacts). The scientific consensus, as reflected in reports by the Intergovernmental Panel on Climate Change and the U.S. Global Change Research Program, indicates that human activities, particularly the combustion of fossil fuels, are the dominant cause of observed warming since the mid-20th century. Global average temperatures have increased approximately 1.1 degrees Celsius above pre-industrial levels, and current trajectories are projected to result in significant further warming with associated impacts on sea levels, extreme weather, agriculture, ecosystems, and human health.

The federal approach to climate policy has shifted between administrations, with significant regulatory actions under executive authority rather than comprehensive climate legislation. The Supreme Court's decision in Massachusetts v. EPA (2007) established that greenhouse gases are air pollutants subject to regulation under the Clean Air Act, providing EPA with authority to regulate emissions from mobile and stationary sources. However, West Virginia v. EPA (2022) limited EPA's ability to use Section 111 to mandate generation-shifting in the power sector.

EPA regulates greenhouse gas emissions from several source categories under the Clean Air Act, including light-duty vehicle tailpipe standards, heavy-duty vehicle standards, and new source performance standards for power plants. The Inflation Reduction Act's climate provisions operate primarily through the tax code, providing production and investment tax credits for clean energy, consumer credits for electric vehicles and home energy improvements, and grants for methane reduction, environmental justice, and climate-smart agriculture. The IRA also includes provisions for federal procurement of clean energy, climate adaptation on federal lands, and accelerated deployment of clean energy technologies.

Federal adaptation programs span multiple agencies, including FEMA's hazard mitigation grants, NOAA's climate services, the Army Corps of Engineers' flood risk management, USDA's conservation programs, and HUD's Community Development Block Grant-Disaster Recovery program. The National Climate Assessment, mandated by the Global Change Research Act of 1990, provides periodic assessments of climate change impacts across the United States.

Climate mitigation options include maintaining and expanding IRA clean energy incentives, establishing a clean electricity standard or carbon pricing mechanism, strengthening EPA vehicle emission standards, regulating methane emissions from oil and gas operations, and investing in carbon capture and direct air capture technologies. The scope of EPA's regulatory authority following West Virginia v. EPA remains a significant legal and policy question.

Adaptation options include increasing federal investment in climate-resilient infrastructure, reforming flood insurance and disaster assistance programs to encourage risk reduction, supporting climate adaptation in agriculture and water management, and strengthening building codes and land use planning in climate-vulnerable areas. The concept of a just transition for workers and communities dependent on fossil fuel industries is a cross-cutting policy consideration, with proposals including economic diversification grants, workforce training programs, and preferential access to clean energy investments.

Implementation of IRA climate provisions has proceeded, with clean energy investment accelerating across the country. EPA has finalized new power plant emission rules and strengthened vehicle emission standards, though these face legal challenges. International climate negotiations at COP28 and COP29 have produced agreements on transitioning away from fossil fuels, loss and damage financing, and a new collective climate finance goal. Congressional debates have focused on the cost and effectiveness of IRA provisions, the appropriate role of EPA regulation versus congressional action, and the balance between climate action and energy security.