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New Connecticut Greenhouse Gas Inventory Report Shows Overall Emissions Decline but Need for Further, Faster Reductions

State Met 2020 Reduction Goal; Must Accelerate Reductions To Meet 2030 Goal Set by Legislature

(HARTFORD, CT) – The Connecticut Department of Energy and Environmental Protection (“DEEP”) published its latest Greenhouse Gas Emissions (“GHG”) Inventory, the most comprehensive accounting of the state’s air pollution that contributes to climate change. While the state is making progress, there is work to be done to meet pollution reduction goals set by the legislature. The legislature established those goals to improve the health of Connecticut residents, create opportunities for Connecticut businesses, and reduce energy costs for all Connecticut residents.

In 2019, Connecticut had economy-wide emissions of 39.3 million metric tons of carbon-dioxide equivalent (“MMTCO2e”) — a decrease of 13.9 percent since 1990. The peak was nearly 53 MMTCO2e in 2004. The pandemic contributed to a low of 32.7 MMTCO2e in 2020, but estimates for 2021, with vehicle use back up, showed emissions approaching pre-pandemic levels.  

“We are continuing our urgent work to do our part to mitigate the threat of climate change,” said DEEP Commissioner Katie Dykes. “While we’ve made strides and met our 2020 target, we have much work ahead of us and only seven years to achieve our 2030 goal. The transportation sector continues to be by far the largest source of our emissions, followed by residential sector emissions. With climate change already impacting residents’ health, as well as our environment and our economy, we need the feasible policy solutions proposed in this report, before it’s too late.”

“It’s encouraging to see the work Connecticut has done on climate change mitigation is beginning to show results, but we have additional work to do,” said House Environment Committee Chair Rep. Joe Gresko, D-Stratford. “We need to do the work now to achieve these ambitious goals.”

“I’d like to thank Commissioner Dykes and the staff at DEEP for this comprehensive report,” said Climate Caucus Chair Rep. Brandon Chafee, D-Middletown. “It not only documents the progress we’ve made in meeting our reduction goals, but it also provides a clear roadmap of policies to keep us on target in the future. I look forward to working with DEEP and my fellow legislators to turn these proposals into law, ensuring future generations have a healthy environment and stable climate.”

“The GHG Emissions Inventory – regardless of the numbers – is a reminder that we need to be laser focused on taking action to address climate change,” said Nathan Frohling, Director of External Affairs for The Nature Conservancy of Connecticut. “Making significant progress every year is critical to meeting the greatest challenge we face to life on earth as we know it.”

The data provides a report card detailing 30 years of emissions, back to 1990, and includes estimates for 2021 emissions. Transportation remains the top emitter in the state and has not decreased significantly from 1990 levels. The report concludes by identifying a range of policy options to further reduce emissions and their associated impact, recognizing that the negative impacts of climate change and air pollution are often concentrated in Connecticut’s most overburdened communities.

Other high-level takeaways from the report include:

  • Transportation in 2019 remains the largest source of emissions in the state, accounting for 40% of the state’s climate pollution, with the sector’s emissions essentially unchanged since 1990 even as fuel efficiency has increased, thanks to increased driving miles.
  • Residential heating surpassed the electric power sector as the 2nd largest emitter.
  • Electric sector emissions were down 52% in 2019 from 1990 levels.
  • In 2019 and 2020 (as in 2018), the transportation, electricity, and residential sectors together accounted for nearly three-quarters of Connecticut’s GHG emissions.
  • 2020 and 2021 saw significant declines in GHG emissions that were almost entirely induced by the COVID-19 pandemic and largely the result of reduced personal vehicle use.

The report’s proposed policy solutions include an update to the state’s Global Warming Solutions Act via SB 1145 so that it aligns with the climate change science detailed in the latest Intergovernmental Panel on Climate Change report, as well as other policies and legislation currently being considered by the Legislature, such as Governor Lamont’s SB 979, which would adopt home energy labeling and increase urban tree cover.

The state first set targets in 2008, passing legislation which established a mandate to reduce statewide GHG emissions 10 percent below 1990 levels by 2020 and 80 percent below 2001 levels by 2050. In 2018, to guide progress toward the 2050 target, the legislature added a medium-term target of 45 percent emissions reductions below the 2001 level by 2030. Last year, the legislature codified Governor Lamont’s Executive Order 3 with the passage of Public Act No. 22-5, requiring Connecticut’s electrical grid to be carbon free by 2040.

For the complete report, please visit DEEP_GHG_Report_90-21_Final.pdf (, and for a slide deck summary, please visit Connecticut GHG inventory update for 1990-2021

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