Greenhouse gas emissions increase in U.S.

WASHINGTON — The amount of U.S. greenhouse gases flowing into the atmosphere, mainly carbon dioxide from burning fossil fuels, increased last year by 1.4 percent after a decline in 2006, the Energy Department reported Wednesday.

The report said carbon dioxide, the leading pollution linked to global warming, rose by 1.3 percent in 2007 as people used more coal, oil and natural gas because of a colder winter and more electricity during a warmer summer. Half of the country's electricity is generated by coal-burning power plants.

A shortage of hydropower also contributed to an increase in the demand for fossil fuels, said the department's Energy Information Administration.

The EIA said that in 2007 the United States produced 8 billion tons (7.28 billion metric tons) of greenhouse gases, compared to 7.9 billion (7.18 billion metric tons) in 2006. The tonnage, presented in terms of "carbon dioxide equivalent" also includes methane, nitrous oxides and a number of lesser greenhouse gases, although carbon dioxide accounted for nearly 83 percent of the releases.

Despite a growing concern about the accumulation of heat-trapping pollution that scientists say is changing the world's climate, the flow of greenhouse gases continue to increase not only in the United States, but worldwide.

U.S. greenhouse gases have increased 16.7 percent since 1990, or an average of 0.9 percent a year, the EIA reported. Carbon dioxide emissions have increased an average of 1.1 percent a year since 1990.

Globally the increases have been even more dramatic, according to separate findings by scientists at the Oak Ridge National Laboratory. They showed carbon dioxide output worldwide increased by 3 percent from 2006 to 2007 with a 7.5 percent increase in China, according to data released earlier this year.

"We have not been able to turn our emissions around. We still are increasing our emissions overall," said Brenda Ekwurzel, a climate scientists at the Union of Concerned Scientists.

Last year, President Bush touted the 2006 reduction in U.S. greenhouse gas emissions as evidence that his largely voluntary efforts to address climate change was making headway as carbon dioxide releases dropped 1.3 percent between 2005 and 2006. And Bush also noted the continued drop in "carbon intensity" — carbon dioxide emission increases as related to economic growth — which has declined steadily since 1990.