WASHINGTON -- Alaska Gov. Sarah Palin, who says she'll leave office at the end of the month, is already taking on one national issue, calling the Obama administration's plan to reduce greenhouse gases a threat to the U.S. economy.

In an op-ed piece in Tuesday's Washington Post, Palin attacks the administration's so-called cap-and-trade plan that would allow industrial sources to buy and sell pollution permits.

The plan, Palin writes, is "an enormous threat to our economy. It would undermine our recovery over the short term and would inflict permanent damage."

She adds: "In addition to immediately increasing unemployment in the energy sector, even more American jobs will be threatened by the rising cost of doing business under the cap-and-tax plan."

Instead, the former Republican vice presidential nominee says: "We are ripe for economic growth and energy independence if we responsibly tap the resources that God created right underfoot on American soil. Just as important, we have more desire and ability to protect the environment than any foreign nation from which we purchase energy today."

The climate bill passed by the House last month requires power plants, factories, refineries and electricity and natural gas distributors to reduce the emissions linked to global warming. It also calls for more power production from renewable sources such wind and solar energy, and raises energy-efficiency standards.

Palin surprised political observers when she announced July 3 that she would leave the governor's office while in the middle of her first term. The governor chose not to seek re-election and suggested it was unfair to hold onto the office as a lame duck.

She did take a shot at her critics in her Post essay.

"Unfortunately," Palin wrote, "many in the national media would rather focus on the personality-driven political gossip of the day than on the gravity of these challenges."