Connecticut CO₂ Emissions
Connecticut emitted 37 million metric tons of energy-related CO₂ in 2024, 0.8% of the US total. That ranks it 41st among the 50 states and the District of Columbia, at 10.1 metric tons per person.
Data year 2024 · Source: U.S. Energy Information Administration, State Energy Data System (June 2026)
How much CO₂ does Connecticut emit?
Connecticut produced 37 million metric tons of carbon dioxide from burning fossil fuels in 2024. The United States as a whole emitted 4.78 billion metric tons, so Connecticut accounts for 0.8% of the national total.
Per person, that is 10.1 metric tons, 28% below the US average of 14.1 metric tons. On that measure Connecticut ranks 39th highest of 51.
CO₂ emissions in Connecticut since 1990
Energy-related emissions in Connecticut have fallen by 8% since 1990, from 40 million metric tons to 37 million metric tons. Compared with 2005, the baseline year for many US climate targets and marked on the chart, they have fallen by 15%. Emissions peaked in 1973 at 49 million metric tons and are now 24% below that level.
Emissions by sector
Transportation is the largest source of energy-related CO₂ in Connecticut, at about 41% of the total, followed by electric power at 26% and residential at 18%.
Emissions by fuel
Petroleum produces about 55% of the state’s energy-related CO₂, natural gas 45%.
How Connecticut compares with other states
These are the states closest to Connecticut in the 2024 ranking by total emissions. See the full ranking of all states.
| # | State | Total (Mt) | Share of US | Per person (t) |
|---|---|---|---|---|
| 39 | Nevada | 39.28 | 0.8% | 12.1 |
| 40 | Oregon | 38.94 | 0.8% | 9.1 |
| 41 | Connecticut | 37.09 | 0.8% | 10.1 |
| 42 | Montana | 27.16 | 0.6% | 23.9 |
| 43 | Idaho | 21.11 | 0.4% | 10.5 |
Frequently asked questions
How much CO₂ does Connecticut emit per year?
Connecticut emitted 37 million metric tons of energy-related CO₂ in 2024, which is 0.8% of the US total of 4.78 billion metric tons.
What are the CO₂ emissions per person in Connecticut?
About 10.1 metric tons per person in 2024, 28% below the US average of 14.1 metric tons. That ranks 39th highest of 51.
Have emissions in Connecticut fallen since 2005?
They have fallen by 15% since 2005 and fallen by 8% since 1990. Emissions peaked in 1973 at 49 million metric tons and are now 24% below that level.
What is the biggest source of CO₂ in Connecticut?
Transportation is the largest sector, at about 41% of energy-related emissions, followed by electric power at 26%. By fuel, petroleum accounts for 55%.
About the data. Figures are energy-related carbon dioxide emissions: CO₂ from burning coal, natural gas and petroleum, in million metric tons. Emissions from power plants are counted in the state where the electricity is generated, not where it is used. Other greenhouse gases and non-energy sources such as agriculture are not included.
Source: U.S. Energy Information Administration, State Energy Data System, released June 26, 2026. Latest year available: 2024.
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