The United States produced 7 billion metric tons of carbon dioxide equivalent greenhouse gas (GHG) emissions in 2025, the second largest in the world after greenhouse gas emissions by China and among the countries with the highest greenhouse gas emissions per person. In 2025 China is estimated to have emitted 29% of world GHG, followed by the United States with 12%, then India with 7%. In total the United States has emitted a quarter of world GHG, more than any other country. Annual emissions are over 15 tons per person and, amongst the top eight emitters, it is the highest country by greenhouse gas emissions per person.
The IEA estimates that the richest decile in the US emits over 55 tonnes of per capita each year.IEA (2023), The world's top 1% of emitters produce over 1000 times more than the bottom 1%, IEA, Paris https://www.iea.org/commentaries/the-world-s-top-1-of-emitters-produce-over-1000-times-more-co2-than-the-bottom-1, License: CC BY 4.0 Because coal-fired power stations are gradually shutting down, in the 2010s emissions from electricity generation fell to second place behind transportation which is now the largest single source. In 2020, 27% of the GHG emissions of the United States were from transportation, 25% from electricity, 24% from industry, 13% from commercial and residential buildings and 11% from agriculture.
U.S. energy-related CO2 emissions decreased by 3% in 2023, amounting to a reduction of approximately 134 million metric tons (MMmt). This reduction primarily occurred in the electric power sector, with a significant shift from coal-fired power to less carbon-intense fossil fuels such as natural gas, as well as sustainable energy sources like solar.
In 2021, the electric power sector was the second largest source of U.S. greenhouse gas emissions, accounting for 25% of the U.S. total. U.S. greenhouse gas emissions are contributing to climate change in the United States, as well as worldwide.
Background In context of climate change
Greenhouse gases absorb radiant energy from the Earth after the surface is warmed by sunlight. US emissions in 2022 involved carbon dioxide (, 79.7%), methane (, 11.1%), nitrous oxide (, 6.1%) and other gases (e.g., fluorinated gases, 3.1%).
Greenhouse gases vary in how long they remain in the atmosphere. Though methane and nitrous oxide are more potent greenhouse gasses than , is longer-lived, remaining in the atmosphere for centuries. The average concentration in 2024 was over 424 parts per million (ppm), and exceeded 427 ppm in February 2025—each more than 50% higher than its pre-industrial level. Click "Download data" and use spreadsheet to average monthly values for 2024. Annual US national emissions were exceeded only by those of China, which has four times the US population. Regardless of where emissions occur, the emitted gases spread around the world. This anthropogenic (human-caused) increase in greenhouses gases has impacts on weather patterns, droughts, heat waves, wildfires, ocean acidification, sea level rise, glacial melting, average global temperatures, extinction of species, and so forth.
Sources of greenhouse gases Carbon dioxide enters the atmosphere through the mass burning of fossil fuels such as coal, natural gas, and oil along with trees, solid waste, and biological materials. In 2018, carbon dioxide was estimated to approximately be 81% of all USA greenhouse gases emitted in 2018. Natural sinks and reservoirs absorb carbon dioxide emissions through a process called the carbon cycle. Sinks and reservoirs can include the ocean, forests and vegetation, and the ground.
Methane is mainly produced by livestock and agricultural practices. Methane was estimated to make up 10% of emitted greenhouse gases. From the decrease in non-agricultural GHG emissions during COVID-19, the percent of the USA's GHG emissions from livestock increased from 2.6% to about 5%, which is a smaller percentage than many other countries likely because the USA has more greenhouse gas emissions from vehicles, machines, and factories. Nitrous oxide is a greenhouse gas produced mainly by agriculture. Fluorinated gases are synthetically produced and used as substitutes for stratospheric ozone-depleting substances.
Greenhouse gases are produced from a wide variety of human activities, though some of the greatest impacts come from burning fossil fuels, deforestation, agriculture and industrial manufacturing. In the United States, power generation was the largest source of emissions for many years, but in 2017, the transportation sector overtook it as the leading emissions source. As of that year, the breakdown was transportation at 29%, followed by electricity generation at 28% and industry at 22%.
After carbon dioxide, the next most abundant compound is methane, though there have been methodological differences in how to measure its effects. According to a 2016 study, US methane emissions were underestimated by the EPA for at least a decade, by some 30 to 50 percent.
Another area of concern is that of ozone-depleting substances such as chlorofluorocarbons (CFCs) and hydrofluorocarbons (HFCs), which are often potent greenhouse gases with serious global warming potential (GWP). However, significant progress has been made in reducing the usage of these gases as a result of the Montreal Protocol, the international treaty that took effect in 1989.
Major emissions-creating events In February 2018, an explosion and blowout in a natural gas well in Belmont County, Ohio was detected by the Copernicus Sentinel-5P satellite's Tropospheric Monitoring Instrument. The well was owned by XTO Energy. About 30 homes were evacuated, and brine and produced water were discharged into streams flowing into the Ohio River. The blowout lasted 20 days, releasing more than 50,000 tons of methane into the atmosphere. The blowout leaked more methane than is discharged by most European nations in a year from their oil and gas industries.
Reporting requirement Reporting of greenhouse gases was first implemented on a voluntary basis with the creation of a federal register of greenhouse gas emissions authorized under Section 1605(b) of the Energy Policy Act of 1992. This program provides a means for utilities, industries, and other entities to establish a public record of their emissions and the results of voluntary measures to reduce, avoid, or sequester GHG emission
In 2009, the United States Environmental Protection Agency established a similar program mandating reporting for facilities that produce 25,000 or more metric tons of carbon dioxide per year. This has resulted in thousands of US companies monitoring and reporting their greenhouse gas emissions, covering about half of all GHG emissions in the United States.
A separate inventory of fossil fuel emissions is provided by Project Vulcan, a NASA/DOE funded effort to quantify North American fossil fuel emissions over time.
Mitigation
Federal Policies The United States government has held shifting attitudes toward addressing greenhouse gas emissions. The George W. Bush administration opted not to sign the Kyoto Protocol,Dessai, S. (December 2001), Tyndall Centre Working Paper 12: The climate regime from The Hague to Marrakech: Saving or sinking the Kyoto Protocol?, Norwich, UK: Tyndall Centre, archived from the original on 31 October 2012. p. 5. but the Obama administration entered the Paris Agreement. The Trump administration withdrew from the Paris Agreement while increasing the export of crude oil and gas, making the United States the largest producer.
In 2021, the Biden administration committed to reducing emissions to half of 2005 levels by 2030. In 2022, President Biden signed the Inflation Reduction Act into law, which is estimated to provide around $375 billion over 10 years to fight climate change. the social cost of carbon is 51 dollars a tonne whereas academics say it should be more than three times higher.
Carbon neutrality Reducing U.S. greenhouse gas emissions to the point where carbon emissions are neutral compared to the absorption of carbon dioxide is often called "net zero". Like the European Union, and countries worldwide, the United States has implemented carbon neutrality measures and law reform at both federal and state levels: The Biden Administration had set a goal of reducing carbon emissions by 50% to 52% compared to 2005 levels by 2030, a carbon free power sector by 2035, and for the entire economy to be net zero by 2050.FACT SHEET: President Biden to Catalyze Global Climate Action through the Major Economies Forum on Energy and Climate (April 20, 2023) By April 2023, 22 states, plus Washington DC and Puerto Rico had set legislative or executive targets for clean power production. All cars or light vehicles will have zero emissions (i.e. no internal combustion engine with gas or diesel) by 2035 in light duty vehicles, and no longer be bought by federal government by 2027.Executive Order 14057 The California Air Resources Board voted in 2022 to draft new rules banning gas furnaces and water heaters, and requiring zero emission appliances in 2030.'California plans to phase out new gas heaters by 2030' (23 September 2022) NPR By 2022, four states have gas bans in new buildings.S&P Global (9 June 2022) Market Intelligence
Federal policies and legislation Federal action plays a pivotal role in the U.S. approach to carbon neutrality, influencing energy systems, transportation, and industrial emission through a mic of legislative and executive tools.
The U.S. federal government has implemented several major policies to advance carbon neutrality, primarily through legislation, regulations, and executive actions. The Inflation Reduction Act (IRA) of 2022 is the most significant climate law in U.S. history, allocating $369 billion to clean energy and emissions reduction. It includes tax credits for renewable energy projects, electric vehicles, and carbon capture technology, aiming to cut U.S. greenhouse gas emissions by 40% below 2005 levels by 2030. Independent analyses suggest the IRA could reduce emissions by up to 42% by 2030 if fully implemented. A 2025 peer-reviewed study highlights the IRA's role in accelerating sustainable energy transitions, particularly through green hydrogen development, which could contribute to reducing global CO2 emissions by up to 6 gigatons when combined with other clean energy initiatives.
Prior to the IRA, the Clean Power Plan (2015) was a key Obama-era policy to reduce emissions from power plants, but it was repealed in 2019. In 2022, the Supreme Court limited the EPA's authority to regulate power plant emissions in West Virginia v. EPA, though the agency retains some power to set standards. The Biden administration has since proposed new rules requiring coal and gas plants to adopt carbon capture or shut down by 2040.
Federal agencies are also working toward carbon neutrality. In 2021, President Biden signed Executive Order 14057, mandating that the federal government achieve net-zero emissions by 2050. This includes transitioning to 100% carbon-free electricity by 2030 and electrifying the federal vehicle fleet. , the Department of Defense - the largest federal energy consumer — plans to increase renewable energy use; specific targets are outlined in its Climate Adaptation Plan.
Despite these efforts, challenges remain. The U.S. Energy Information Administration (EIA) projects that fossil fuels will still provide about 60% of U.S. electricity in 2050 under current policies. Legal battles and shifting political priorities could also delay implementation. For example, some IRA tax credits face opposition in Congress, and future administrations could roll back regulations. While these initiatives mark historic progress, their long term success will depend on sustained political commitment, robust legal frameworks, and technological scalability.