SAN FRANCISCO - Google Inc., Gap Inc., Pacific Gas & Electric Co. and other firms pledged Thursday to cut their greenhouse gas emissions and help make the Bay Area a leader in combating global warming.

More than two dozen companies joined the Business Council on Climate Change, a coalition of Bay Area businesses that promise to report and reduce carbon emissions, share the best green practices and advocate for policies to address global warming.

"If the environment fails, markets fail. As contributors to the problem, companies have a responsibility to act," said Gavin Power of the United Nations Global Compact, which seeks to promote corporate responsibility.

The BC3 coalition was launched at San Francisco City Hall Thursday at an event aimed at encouraging more businesses to join. The initiative is being organized by the Bay Area Council, city of San Francisco and UN Global Compact, which plans to promote the business-led initiative as a model for other cities and businesses worldwide.

Coalition leaders say being green is good for business and want to change the perception that curbing emissions of heat-trapping gases will result in job losses and lower profits.

"For the region, we think it has tremendously beneficial economic implications," said Jim Wunderman, president of the Bay Area Council, a business advocacy group. "This region is going to be at the center of the technological innovation that's going to solve this problem. We think we're actually going to produce good, meaningful jobs right here."

Mountain View-based Google is committed to helping combat global warming, said Robyn Beavers, who heads its corporate environmental programs.

The Internet search leader offers employees a free shuttle service on buses that run on biodiesel, is working to boost its energy efficiency and serves locally grown, organic food at its company cafes. The firm is also installing more than 9,200 solar panels that could provide as much as 30 percent of electricity at its famed headquarters, Beavers said.

"Everything we've done makes business sense," Beavers said. "There are great ways to be a better environmental player and be a better company."

PG&E, which provides electricity for much of Northern California, seeks to be a strong advocate for policies that curb global warming, said Nancy McFadden, a senior vice president.

The San Francisco-based utility, which generates half its electricity from carbon-free sources, supported California's landmark bill to cut greenhouse gas emissions and backs federal legislation to cap emissions and allow power companies to trade pollution credits.

"Businesses can be credible, important and forceful advocates on the issue of climate change," she said.

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Business Council on Climate Change: http://www.bayareacouncil.org/bc3