Connecticut is running behind its goal of cutting greenhouse gas emissions by 2030 despite some progress, according to a new report from the state’s Department of Energy and Environmental Protection.
The agency’s latest Greenhouse Gas Emissions Inventory report shows that emissions from the state’s two largest sources decreased in 2023, but emissions still rose by 1.5% to reach 35 million metric tons. Despite the increase, emissions remain 9.5% below pre-pandemic levels in 2019, the report says.
Emissions of carbon dioxide — the main contributor to human-induced climate change — decreased in both the transportation sector and from buildings in 2023. The state’s largest source of CO2 emissions comes from the transportation sector, which includes trucks, cars, trains and planes, according to the agency. Vehicle emissions dropped by 2% in 2023, despite an increase in vehicle miles driven. The agency said that the drop is most likely due to more fuel efficient and light-duty vehicles on the roads.
Gasoline is the largest source of emissions by fuel type, accounting for almost 73% of the total emissions in the transportation sector, according to the report. Gasoline consumption in transportation fell by 3.4% in 2023, showing the rise of electric vehicles on Connecticut roadways with less dependence on gasoline, an overall good sign for the state’s goals.
“The declining trend and the emissions reduction in 2023, despite vehicle miles traveled increasing, are encouraging because transportation remains Connecticut’s largest contributor to CO2 emissions. Reducing emissions in this sector is critical to achieving the state’s economy-wide CO2 reduction goals,” the report says.
Residential building sector emissions also declined by 5.6%, according to the agency. The report mentioned that a mild winter in 2023 likely drove the reduction in emissions in the residential building sector, complimented by weatherization and energy-efficiency measures.
In 2023, 78% of Connecticut’s home heating requirements were met by natural gas, heating oil or propane, while 19% were met by electricity either through electric resistance heating or heat pumps, according to the report. The agency said this translates to approximately 285,000 of Connecticut’s 1.5 million households meeting their heating needs through electricity. The overall number is relatively the same from 2022, where 79% of households met their heating demand with fossil fuels.
Despite reductions in greenhouse gas emissions in two of the largest energy sectors, electric power emissions increased by 4.2%. The report said the increase is most likely due to the Millstone nuclear plant having a prolonged outage in 2023 due to refueling, resulting in a lower energy production in 2023. As a result, the state’s electric power consumption relied more on fossil fuels during this period.
The state aims for economy-wide net-zero greenhouse gas emissions by 2050, with interim targets of 45% reduction by 2030 and 65% by 2040, all relative to 2001 levels. In 2020, Connecticut met an emission reduction goal set by the state’s 2008 Global Warming Solutions Act, according to DEEP.
But reaching the next goal — a 45% reduction in GHG emissions from 2001 levels by 2030 — requires an average reduction of 1.1 metric tons of carbon dioxide equivalent each year between 2022 and 2030. Connecticut is not on track to meet this goal with current reduction levels, under by about 5% of the emission reduction goal of 45% set by 2030, according to the agency.
“While the state met its 2020 goal, deeper cuts to emissions must be made to reach the 2030 target of 45% below 2001 levels by 2030. If emissions were assumed to continue declining at the average rate achieved in the two decades since peaking in 2004, the state would be 40% below 2001 levels by 2030,” the report says.
This year’s report coincided with the U.S. Environmental Protection Agency announcing plans to repeal the “endangerment finding,” which concluded that greenhouse gases pose a threat to public health and the environment.
Despite this, the Asthma and Allergy Foundation said that emergency room visits due to asthma are on the rise in Hartford — and the increase in health challenges due to asthma has earned the city the number seven ranking out of 100 cities in its 2025 Asthma Capitals report. The report cites emissions as a main component to environment induced asthma in U.S. cities.
“Poor air quality exacerbates existing health problems and creates new ones, affecting both immediate and long-term wellbeing,” Connecticut Department of Public Health commissioner Manisha Juthani said in a statement.
“Greenhouse gas emissions significantly impact human health by contributing to climate change, which in turn leads to various health problems including respiratory illnesses, heat-related illnesses, infectious disease outbreaks, food and water insecurity and mental health issues. Amid the EPA pulling back on these efforts, Connecticut will hold our values to protect and improve the health and safety of our residents.”
Stephen Underwood can be reached at sunderwood@courant.com.