2021 CEQ Annual Report

Air Quality

Air Days               Air Pollutants

Climate Changers

Quick Summary - x check xClimate Change Indicator





Per-capita carbon dioxide equivalent (CO2e) emissions increased in 2018 and the State is not on track to meet the 2030 and 2050 goals.


There was a 2.7 percent increase in total greenhouse gas (GHG) emissions* from 2017 to 2018 (the most recent available data). The largest increases from 2017 were in the residential sector  (14.7%), the commercial sector (9.75%), and for electric power generation (21.9%). In 2018, transportation again accounted for the most CO2e emissions at 37.4 percent, while electric generation, industry, and the commercial/residential sector accounted for 19.7 percent, 16.2 percent, and 28.3 percent, respectively.** While Connecticut has made progress in reducing emissions of GHG in most sectors since 1990, the commercial and industrial sectors’ emissions have increased. In 2018, the State’s CO2e emissions were 7.3 percent below 1990 emission levels, 17.8 percent below 2001 emission levels, and 24 percent below the level reported in 2004.3

Data on vehicle fuel sales was used to derive CO2 emissions associated with the combustion of gasohol and diesel fuel for transportation for non-governmental customers. The data indicates that fiscal years (FY) 2018 and 2019 had the highest levels of CO2 emissions since fiscal year 2011.4


The effect of the pandemic on transportation is evident in the amount of gasohol sold in the state to non-governmental consumers, which declined by 9.1 percent from FY 2019 to FY 2020, and 4.0 percent from FY 2020 to FY 2021. The biggest monthly decline in motor fuel sales in Connecticut occurred in April 2020, which was 40.6 percent less than the gallons sold in April 2019.5

Greenhouse Gas Emissions from Stationary Sources Increased in 2020


Facility-level data from the Environmental Protection Agency (EPA) indicates that large increases in GHG emissions occurred in electricity generation in 2018, 2019 and 2020 from 2017 levels. These facilities in the “power plant” sector reported an approximately 27 percent increase from 2017 to 2020 and a 13 percent increase from 2019 to 2020.6*** This is consistent with the Council’s analysis of the electric generation data that indicated a significant increase in fossil fuel generation from 2017 to 2020. In addition, per capita residential electric sales increased and energy conservation (electric) decreased from 2017 to 2020.CO2 gauge MT CO2e_Capita 2018 with title

The needle in the chart depicts the average annual per-capita reduction (0.15 metric tons per capita) of CO2 emissions from 2008-2018. The per capita reduction needed to achieve the 2050 goal, based on the current population, is 0.28 metric tons per year.

Goal: State law sets two goals for greenhouse gas emissions: reduce statewide emissions to 10 percent below 1990 levels by 2021 and 80 percent below 2001 levels by 2050. Governor Lamont’s Executive Order 3, set a mid-term reduction target of 45 percent below 2001 levels by 2030. The Governor’s Council on Climate Change (GC3) released their report in January 2021 with additional recommendations to reduce state-wide GHG emissions.  

Technical Note: *Emissions are reported in terms of carbon dioxide equivalence (CO2e, i.e., CO2 and other gasses with equivalent climate warming impact), also referred to as greenhouse gases (GHG). While carbon dioxide is the primary GHG, emissions of other GHGs are expressed on the basis of their potential to contribute to global warming, relative to carbon dioxide’s potential. Values from previous reports have been updated based on more current data. The goals on the chart above have been adjusted to account for the growth in population that is projected for 2030 and 2050. **Percent of Consumption-based Accounting Total. ***The “power plant” sector made up 80 percent of GHG emissions from large facilities in Connecticut in 2018, while the “chemicals” sector made up less than 0.2 percent of GHG emissions from large facilities in Connecticut in 2018.  Natural gas (NG).


3 DEEP, Climate Change, 2018 Connecticut Greenhouse Gas Emissions Inventory; portal.ct.gov/-/media/DEEP/climatechange/GHG_Emissions_Inventory_2018.pdf
Department of Revenue Services (DRS), Motor fuel sold to non-governmental customers. DRS Annual Reports, portal.ct.gov/DRS/DRS-Reports/Annual-Reports/Department-of-Revenue-Services-Annual-Reports
DRS, Motor Fuel Comparison Report, Fiscal Years 2019-2020 compared to Fiscal Years 2020-2021; portal.ct.gov/-/media/DRS/Research/ComparativeMotorFuel/Schedule-A--B-1920FY20.pdf
Environmental Protection Agency (EPA), Facility Level Information on Greenhouse Gases Tool; ghgdata.epa.gov/ghgp/main.do Includes power plants, petroleum and natural gas systems, chemicals, waste, metals, pulp and paper, and other emissions.