Map: CO2 Emissions by State

Last week, Environmental Protection Agency Administrator Lee Zeldin announced a repeal of Biden-era greenhouse gas regulations for power plants. The agency touted the move as the “largest power sector deregulatory action in U.S. history.”

Responses to the announcement from government climate action networks emphasized health risks from power plant pollution. “EPA has a statutory obligation to regulate significant sources of pollution that threaten public health, and power plants are among the largest sources in the country,” said Gina McCarthy, EPA administrator during the Obama administration.

The policy change will also affect emissions of CO2, the greatest contributor to atmospheric warming. At the national level, the electric power sector accounts for about 30 percent of energy-related CO2 emissions. Power plants that burn coal, natural gas and petroleum account for 99 percent of CO2 emissions from utility-scale electricity generation, according to the U.S. Energy Information Administration.

This isn’t the first step away from past efforts to control emissions. In February of this year, the EPA rescinded a 2009 finding that atmospheric concentrations of greenhouse gases “threaten the public health and welfare of current and future generations.” That eliminated a legal prerequisite for federal greenhouse gas standards for motor vehicles in the Clean Air Act. Accordingly, the EPA also announced the repeal of greenhouse gas emission standards for light, medium and heavy duty vehicles. Almost 40 percent of U.S. CO2 emissions come from the transportation sector.

Air pollution, like water pollution, creates risks without boundaries. A look at state-by-state CO2 emissions in 2024 reveals considerable variety in total emissions (which have local, national and global impacts) and emission sources.

Texas is both the nation’s leading producer of renewable energy and its greatest CO2 emitter (see map). Contributions from its energy sector make up about a third of these emissions, transportation 27 percent. California comes next, with total CO2 emissions about half that from Texas. About 10 percent come from the power sector. Vehicle emissions make up about 57 percent.

Vermont, Rhode Island, Delaware, New Hampshire, South Dakota, Maine and Hawaii have the lowest totals, all under 20 million metric tons. (Driving a typical gas-powered car 2,500 miles would result in one metric ton of CO2 emissions.)

Half of total CO2 emissions in Alaska come from industry, less than 7 percent from power generation. By contrast, the electricity sector accounts for around 60 percent of emissions in Wyoming and West Virginia.

At present, 24 states have 100 percent clean energy goals. Most have set targets well into the future — 2040 or later — but reaching them depends on policy implementation and investments now.

State-level efforts to regulate emissions have faced pushback from the federal government under the second Trump administration — an April 2025 executive order directed the U.S. attorney general to identify state laws and policies at odds with the objective of “unleashing” American energy.

In May 2025, the U.S. Department of Justice announced lawsuits against Hawaii, Michigan, New York and Vermont over state laws penalizing fossil fuel companies for impacts from greenhouse gas emissions.

The Michigan suit was dismissed by a federal judge in January of this year, but the executive order still stands. It remains to be seen how much time the Department of Justice will devote to new cases challenging state emissions policies.