Minnesota's greenhouse gas emissions fell about 3 percent from 2005 through 2010, but it's uncertain whether that trend will continue.

Emissions from electricity production and from transportation -- cars and trucks, primarily -- led the declines. Utility emissions fell 13 percent, and transportation emissions dropped 10 percent.

But industrial emissions from factories and other industrial sources pushed total emissions back upward by 2 percent from 2009 to 2010 alone.

That's a symptom of the Minnesota economy picking up speed, said David Thornton, assistant commissioner of the Minnesota Pollution Control Agency, which prepared the biennial emissions report for the opening of the legislative session.

"We're not sure about where it's going to stabilize," Thornton said. Emissions from transportation are likely to continue to fall as automakers work toward raising the current mandated average fuel efficiency from 29 miles per gallon to 54.5 in 2025, he said. Emissions from electricity production are also likely to continue declining because of a shift away from coal to cleaner natural gas and renewables in recent years, Thornton said.

"We're relying more on wind power and natural gas, and that's had an impact on emissions," he added. "Beyond that, it's hard to speculate."

Greenhouse gases are seen as the chief cause of the warming climate in Minnesota and around the globe. The Minnesota Legislature in 2007 set a goal of a 15 percent reduction in greenhouse gas emissions from 2005 levels by 2015. Thornton said he was "doubtful" the state could get there based on the recent trends.

"We've got a little too far to go and not enough time to get there," he said.

J. Drake Hamilton, science policy director for the renewable-energy advocacy group Fresh Energy, likewise noted that the report did not address the gap between current emissions and the longer-term goal of a 30 percent reduction by 2025. She added that the state needs to have an emissions-reduction strategy in place in addition to the goals.

However, she was encouraged that the greatest emissions reductions in the past five years came in the sectors that have the most emissions -- electricity production and transportation.

"To get the biggest bang for your buck, you have to start with those sectors," she said.

Ellen Anderson, energy adviser to Gov. Mark Dayton, added that the industrial sector, which includes mining, manufacturing and construction, could be on the verge of reducing emissions because expanding after the recent recession might also require modernizing.

That will require significant investment, Anderson noted, but there could be payoffs.

"There's still a tremendous opportunity for more energy efficiency in large industries," she said. "There are ways they can continue to grow, expand and produce more jobs and output, and not necessarily increase their greenhouse gas output at the same time."

The MPCA report will be presented Thursday to the Senate Environment and Energy Committee.

Bill McAuliffe  612-673-7646