Emissions under scrutiny

Experts: National policies needed

Researchers told the state's global climate change task force Tuesday that emissions from power plants and vehicles account for three-fourths of the nation's man-made carbon dioxide, a potent greenhouse gas.

David Greene, a transportation researcher at the Oak Ridge National Laboratory in Tennessee, said improving the fuel efficiency of cars and trucks could make the largest single contribution to reducing greenhouse gases of any change in the transportation sector.

Greene said gas mileage standards set in the late 1970s save 50 billion gallons of gasoline a year.

Except for modest increases in fuel efficiency standards for light-duty trucks and sport utility vehicles that were passed in March, Greene said, the standards haven't changed significantly since 1985.

"It's not likely to occur voluntarily," Greene said.

Scientists generally agree that the increasing amount of carbon dioxide in Earth's atmosphere will cause global temperatures to rise, though there is debate about how much they would increase and how quickly.

The Legislative Commission on Global Climate Change, created seven months ago, will determine whether North Carolina should adopt goals or policies to lower emissions of greenhouse gases. If it decides that such policies are needed, the commission will make a recommendation to the General Assembly by November.

Echoing Greene, Edward Rubin, director of the Center for Energy and Environmental Studies at Carnegie Mellon University, said national policies are needed for significant reductions in power plant emissions -- the largest source of carbon dioxide.

More than half of North Carolina's electricity is generated by burning coal. Rubin said fossil fuels will continue to be used for decades because of the heavy reliance on them to heat homes, run air conditioners and turn on lights.

Rubin noted that some coal-burning power plants in North Carolina are 35 to 55 years old and eventually will have to be retired.

"You're in a situation where you'll have to be worrying about what will replace the plants," Rubin said. "Those decisions will have important consequences on greenhouse emissions."

Marilyn Brown, interim director of the Engineering Science and Technology at Oak Ridge National Laboratory, which conducts research on clean energy, environmental restoration and national security, said improvements in energy efficiency in buildings and appliances would help reduce demand for new power plants and slow the growth in emissions.

"Energy efficiency is the fastest, cheapest, cleanest way to go to meet climate challenges," Brown said.