Indicators:  Leading Environmental Indicators*

Climate Watch

Connecticut residents reduced the pollutants, commonly called greenhouse gases, that trap heat in the earth’s atmosphere. However, the trend of driving more miles every year threatens to undermine the overall effort to reach the goal.

Certain gases in the air function like the glass of a greenhouse: they allow the sun's energy to pass through, then trap the heat that radiates from the ground. They often are called "greenhouse gases." Worldwide, a build-up of greenhouse gases is contributing to the ongoing rise in temperature. Carbon dioxide is the greenhouse gas emitted in greatest volume, but it is not the most powerful. Methane and other less common gases have much greater ability to trap heat. In 2003, the Department of Environmental Protection (DEP) estimated Connecticut's emissions of all greenhouse gases for the years 1990 through 2000. The quantity of each gas was adjusted according to the strength of its greenhouse characteristics and then reported in a common unit, the Metric Ton of Carbon Dioxide Equivalents.

A state law adopted in 2004 (P.A. 04-252) established goals for future greenhouse gas emissions: return to 1990 levels by 2010, cut back another 10% by 2020, and ultimately achieve a reduction of 75% to 85% from 1990 levels at a date still to be determined. The graph above shows the average Connecticut resident's share of greenhouse gas emissions. The goal line on the graph shows the level of the average resident's share of emissions that must be achieved if the 2010 goal is to be reached. Because there probably will be at least 300,000 more people living in Connecticut in 2010 than there were in 1990, the per capita emissions will have to go below 1990 levels to reach a total state emission level equal to 1990. Most of the carbon dioxide comes from the combustion of fuels in houses, businesses, power plants, and vehicles, and the last of these is the largest source. Connecticut is more energy-efficient than the nation as a whole, and the average Connecticut resident's contribution to global climate change is less than the average American's.

There have been improvements in some emission sources since 2001, such as a reduced use of natural gas in commercial buildings, but those gains have been countered by sharp increases in fuel combustion in homes and vehicles. According to Falling Behind, a report published in March 2008 by the Environment Connecticut Research and Policy Center and the Clean Water Fund, home energy use increased substantially between 2001 and 2005 along with consumption of diesel fuel and gasoline.

Note: Just before this report went to press, the General Assembly adopted and Governor M. Jodi Rell signed An Act Concerning Connecticut Global Warming Solutions (Public Act 08-98), which revised the goals for greenhouse gas emission reductions. The new goals will be shown in next year’s edition of Environmental Quality in Connecticut.

*Leading Environmental Indicators illustrate trends in behavior or practices that can be expected to influence the condition of tomorrow’s air, water, land and wildlife.