Citing financial worries, the State of Arizona has backed out of a broad regional effort to limit greenhouse gas emissions in the West through a cap-and-trade system.

In an executive order issued last week, Gov. Jan Brewer, a Republican, said a cap-and-trade system  which would impose mandatory caps on emissions and allow pollution credits to be traded among companies  would cripple Arizona’s economy.

Instead, the state will support initiatives to expand the use of solar power, nuclear power and other renewable energy sources, said Benjamin Grumbles, the head of the state’s environmental agency.

“The governor thought it was important to be clear and honest and let the W.C.I. partners know that we don’t think that now is the time to implement a cap-and-trade program,” Mr. Grumbles said, referring to the regional effort, the Western Climate Initiative.