Saturday, April 23, 2005

Michigan greenhouse gas emissions on upswing, report finds

By John Flesher / Associated Press

Comment on this story Send this story to a friend Get Home Delivery

TRAVERSE CITY -- Emissions of "greenhouse gases" believed to cause global warming have risen in Michigan, underscoring the need for conservation and greater reliance on alternative energy sources, a scientific report says.

University of Michigan researchers this week released findings from the first statewide inventory of such emissions. They were 9 percent higher in 2002 than in 1990, the report said.

The nationwide rate of increase during the same period was 13 percent. But Michigan's slightly better showing was a long way from the sharp cutbacks needed to halt the worldwide warming trend, said Gregory Keoleian, an assistant professor who oversaw the study.

"We're going in the opposite direction," Keoleian, co-director of the Center for Sustainable Systems in the School of Natural Resources and Environment, said Friday.

The U.S. Environmental Protection Agency began encouraging states to measure greenhouse gas emissions in the early 1990s. Michigan is the 41st state to do so. The state Department of Environmental Quality asked the university last year to conduct the inventory because the DEQ didn't have the money, said David Mason, an analyst with the Air Quality Division.

The report described the inventory as "a necessary first step for the state in developing a meaningful plan to address global climate change."

The inventory measured emissions of carbon dioxide, methane, nitrous oxide, perfluorocarbons, hydrofluorocarbons and sulfur hexafluoride. It was based largely on data collected by government agencies and industry, Keoleian said.

Climate scientists say these gases trap heat from solar radiation that bounces off the Earth's surface, keeping it within the atmosphere and gradually boosting the planetary temperature. The effect is similar to how a greenhouse retains the sun's heat.

Altogether, Michigan's emissions totaled 62.59 million metric tons carbon equivalent in 2002, up from 57.42 million in 1990 -- a 9 percent jump. "Carbon equivalent" is a measure of heat-trapping ability.

The growth in emissions generally tracks the rate of population growth in the state over the 12 years, said Pierre Bull, a graduate student who helped write the report.

Carbon dioxide from fossil fuel combustion accounted for more than 85 percent of total emissions. They surged during the study period, in part because of the popularity of sport utility vehicles, light-duty trucks and other gas guzzlers, the report said.

The economic sector that produced the most emissions was electricity generation -- 33 percent of the total both years. Transportation was second with 24 percent in 1990 and 26 percent in 2002, followed by industrial processes, followed by commercial and residential activity and farming.

The report urged the state to require utilities to produce energy more cleanly and make greater use of renewable sources.

A 2003 report by the Union of Concerned Scientists predicted Michigan's average climate would rise 6 to 10 degrees in winter and 7 to 13 degrees in summer over the next century. That would lengthen the growing season but have negative effects, from less snow for winter tourism to lower Great Lakes water levels, Keoleian said.

"People say, 'Oh, we'd welcome warmer weather,'" he said. "But there would be serious consequences for our economy."

Mason said the DEQ would use the report to analyze trends and develop voluntary programs for greenhouse gas reductions -- possibly with neighboring states. "We're not talking about new regulations here," he said.

On the Net:

Inventory report available at http://css.snre.umich.edu/css--doc/CSS05-07.pdf