U.S. Greenhouse Gas Emissions Rising

The US. emitted the environmental equivalent of 6.8 billion metric tons of carbon dioxide in 2010, up nearly 11% from 1990, according to the U.S. Environmental Protection Agency.

The agency's 2012 U.S. Greenhouse Gas Inventory Report says fossil fuel combustion 32% of it in the transportation sector accounts for about 78% of America's greenhouse gas emissions.

The agency calculates the averages by weighing the relative environmental impact of various pollutants. It says refrigerants used in air-conditioning systems have thousands of times greater global warming potential than CO₂, for example.

Transportation emissions climbed 19% in the 1990s, with cars and light trucks contributing 43% and 19% of the total, respectively. The report attributes the increase to low fuel prices, a 34% jump in miles traveled and a lack of improvement in average fuel economy for the U.S. vehicle fleet.

Gasoline consumption by personal-use vehicles accounted for almost two-thirds of CO₂ emitted by the transportation sector between 1990 and 2010, according to the EPA.

For the U.S. overall, CO₂ represented 90% of emissions from energy consumption in 2010 compared with nearly 93% in 1990. The combustion of fossil fuel accounted for nearly 97% of all CO₂ emitted up about half a percentage point from 1990.

The EPA report says electricity generation consumed 36% of the fossil fuel energy used by the U.S. in 2010 and emitted 42% of all CO₂ attributable to fossil fuel combustion.

The full EPA report can be found HERE.