New Mexico legislators are considering a bill that would, for the first time, set up state controls on greenhouse gas emissions. But the change of administration in Washington, and the resulting prospect of federal regulation, has raised questions about whether the state effort should proceed.

The measure's backers say there are still good reasons to impose a state "cap-and-trade" system as part of the Western Climate Initiative, a regional effort by 11 U.S. states and Canadian provinces to place a limit on greenhouse gas emissions and set up a market to allow industry to trade emissions credits.

The system would cap the overall emissions from the state's 100- or-so largest industrial greenhouse gas emitters. A trading system would allow companies to buy and sell emissions allowances, tapping market mechanisms to find the lowest-cost way of making the needed reductions.

The measure is driven by climate change, which most climate scientists agree is being caused by increases in atmospheric gases released when we burn coal, oil and natural gas. The buildup traps heat much like a greenhouse does, hence the name. Forecast changes include a drier climate and more severe droughts in the Southwest.

"Climate change will hit arid southwestern states like New Mexico the hardest, and we cannot delay implementation of a robust greenhouse gas reduction program," Gov. Bill Richardson said in a written statement. "New Mexico will move forward with states and provinces across North America to implement the Western Climate Initiative cap-and-trade program. Simultaneously, we will work arm- in-arm with the Obama administration to craft a federal program that is based on our work in the West, so that ultimately we will have one North American program."

Representatives of key industries, including utilities and the oil and gas business, say a national system of greenhouse gas regulations is preferable, because it would create a level playing field across the country.

"Climate change is a global problem best addressed through U.S. mandatory action and U.S. global leadership," Jeff Sterba, CEO of electric utility Public Service Company of New Mexico, wrote in a letter last month to Richardson.

The Western Climate Initiative grew in large measure out of state and provincial governments' frustration regarding the lack of federal action on climate change under the Bush administration.

"States are once again taking the lead on combating climate change, while Washington, D.C., sits on its hands," Richardson said two years ago when the plan was announced.