SALT LAKE CITY -- UTAH ENVIRONMENTAL OFFICIALS WANT TO ROLL BACK THE STATE'S GREENHOUSE GAS EMISSIONS TO 2005 LEVELS BY 2020, ROUGHLY A 28 PERCENT REDUCTION.

Rick Sprott, director of the Utah Department of Environmental Quality, said most of the reductions would come through cleaner energy, a cap-and-trade program for emissions, more efficient cars and better transportation systems.

The goal, announced Friday, is ambitious but achievable, he said.

Meeting it would mean 27 million fewer tons of carbon released into the atmosphere, about nine tons less per person than if nothing was done at all, according to state estimates.

The plan is aimed at reducing emissions linked to global climate change, which in Utah is expected to bring more heatwaves, longer growing seasons and earlier snowmelt.

Other states have also set goals for greenhouse gas reductions, some more aggressive than Utah's and others more limited.

"We think that's appropriate," Sprott said. "We have a very high growth rate in Utah which certainly is going to make it a lot more challenging for us to achieve reductions than many other states."

Utah's relies on coal-fired power plants for about 85 percent of its electricity, according to Dianne Nielson, Gov. Jon Huntsman's energy adviser.

Ramping up the state's renewable energy portfolio in the coming decades and improving efficiency in homes and businesses will help cut energy emissions, she said.

State officials are also expecting a cap-and-trade program for industrial polluters -- which hasn't been approved by lawmakers yet -- to also play a role. DEQ officials said the program could be in place by 2012.

Traffic is the other key target. State officials are hoping to see significant pollution reductions by stricter emissions standards starting in 2012, improved mass transit systems and enhanced ride-sharing programs for businesses with more than 100 employees.

Friday's announcement doesn't establish any new policies or regulation but is a goal for the state as it sets future energy policies and a list of ways that target might be met, Sprott said.

"It's one possible combination of policies. In the end we'll probably end up doing different things as the situation changes," Sprott said.

DEQ officials later this year hope to have a more firm grasp of the financial cost of reaching that goal by 2020. They said Friday the costs are "not prohibitive nor will it disadvantage Utah business or families."

Ultimately meeting that 2020 goal will require a broad set of policies -- "carrot and the stick," as Sprott described them -- involving governments, businesses and individual households.

"It's a stretch for us but it's still doable and we have a path to get there," Nielson said.