Salt Lake City Mayor Rocky Anderson has taken his fight against global warming to California, where he hopes to help win approval from the Bush administration for tightening state standards on greenhouse-gas emissions.

Anderson was in Sacramento, Calif., on Wednesday to testify at an Environmental Protection Agency hearing on California's request for a waiver that would allow the state to set stricter standards on greenhouse gases, including carbon dioxide, than are allowed under federal restrictions, which California lawmakers have said are too lax. Greenhouse-gas emissions contribute to global warming.

"We know what an enormous difference can be made if local and state officials are given the freedom to enact these effective measures," Anderson told the panel.

He was invited to testify by California's Sierra Club. A handful of public officials testified, including a number of California state lawmakers and the mayors of Sacramento and West Sacramento, as well as several of Gov. Arnold Schwarzenegger's staff members. Anderson was the only elected official from outside California to testify.

The federal Clean Air Act requires states to abide by federal standards on all classes of pollutants. California alone is allowed to set stricter limitations, although it must solicit a waiver from the EPA on a case-by-case basis for each type of pollutant it seeks to control.

California is now trying to receive that permission to regulate greenhouse gases. Once California is granted a waiver, other states can choose to follow either the federal standards or California's.

At least 11 states are ready to implement California's tougher standards or are actively considering adopting them. Utah is not one of those states, although Utah Gov. Jon Huntsman Jr. this month teamed up with Schwarzenegger, four other Western governors and British Columbia by signing a pact that calls for developing regional benchmarks for reducing emissions.

California's regulations would require that state to reduce greenhouse-gas emissions by 25 percent by 2020. The waiver was requested 18 months ago, and many state politicians say the process has dragged on too long.

Auto-industry representatives told the panel Wednesday that allowing California and other states to set their own standards would result in a "patchwork" of regulations that would be counterproductive and would have no measurable impact on temperatures.