FACTBOX-Obama acts to reverse Bush climate policies

Jan 26 (Reuters) - U.S. President Barack Obama signaled a sharp break with his Republican predecessor George W. Bush's environmental policies on Monday by taking steps to allow states to set stricter limits on greenhouse gas emissions from vehicles.

Obama also ordered the Transportation Department to boost fuel economy standards for cars and trucks for the 2011 model year.

Following are extracts from the presidential memorandums:

* MEMORANDUM FOR THE ADMINISTRATOR OF THE ENVIRONMENTAL PROTECTION AGENCY

The memorandum notes that under the Clean Air Act, the EPA sets emissions standards for new motor vehicles, and says:

"California may also adopt standards for new motor vehicles if the administrator of the EPA, based on criteria set out in the statute, waives the general statutory prohibition on state adoption or enforcement of emission standards."

"Other states may adopt emissions standards for new motor vehicles if they are identical to the California standards for which a waiver has been granted and comply with other statutory criteria."

"In order to ensure that the EPA carries out its responsibilities for improving air quality, you are hereby requested to assess whether the EPA's decision to deny a waiver based on California's application was appropriate in light of the Clean Air Act. I further request that, based on that assessment, the EPA initiate any appropriate action."

* MEMORANDUM FOR THE SECRETARY OF TRANSPORTATION AND THE ADMINISTRATOR OF THE NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION:

The memorandum notes that in 2007, the U.S. Congress passed the Energy Independence and Security Act (EISA), which mandates the transportation secretary, as part of U.S. efforts to achieve energy independence, to prescribe annual fuel economy increases for motor vehicles, beginning with model year 2011.

"Federal law requires that the final rule regarding fuel economy standards be adopted at least 18 months before the beginning of the model year."

"In order for the model year 2011 standards to meet this requirement, the NHTSA must publish the final rule in the Federal Register by March 30." (Compiled by Ross Colvin in Washington; Editing by David Storey)