June 27 (Bloomberg) -- Ford Motor Co. and Chrysler, under pressure to build more climate-friendly vehicles, joined a business-environmental group today urging the U.S. government to set a national cap on global warming pollution through a system of economic credits.

Ford and Chrysler, the second- and fourth-largest U.S. automakers respectively, announced their membership in the U.S. Climate Action Partnership, which proposes cutting carbon dioxide emissions by as much as 30 percent within 15 years through a ``cap-and-trade'' system in which companies could buy and sell carbon credits.

Automakers sparred with environmental groups as recently as last week over proposals to boost fuel economy to help reduce oil consumption and pollution. The industry failed to stop the Senate from approving energy legislation requiring cars and trucks to average 35 miles per gallon of gasoline by 2020.

``Auto companies have raised cynicism to a high art form,'' Dan Becker, director of the global warming program at the Sierra Club in Washington, said in an interview. ``It's interesting they are making this green move after the Senate passed the first changes to fuel economy standards in 30 years.''

The move was spurred by U.S. Representative John Dingell, a Michigan Democrat, who asked the chief executive officers of GM, Ford and Chrysler at a March 14 hearing to publicly commit to a program limiting carbon emissions, said John DeCicco, an automotive policy specialist at the New York-based advocacy group Environmental Defense, a member of the coalition.

Climate Policy

The auto industry prefers a climate policy that would regulate both oil companies and automakers, rather than mileage requirements under the Corporate Average Fuel Economy or CAFE standards aimed only at auto manufacturers, DeCicco said.

Chrysler is spending $3 billion on factories to build more fuel-efficient cars and trucks. Ford is spending $866 million at six factories in part to make more efficient transmissions. Ford and Chrysler join General Motors Corp., which signed on to the partnership last month.

``Now is the time for advancing a national approach to climate change where all of us -- individuals, industry and government -- take action toward reducing emissions of greenhouse gases,'' Tom LaSorda, CEO of Auburn Hills, Michigan- based Chrysler, said in a statement.

The cap-and-trade system would create a market in which carbon emitters, such as power plants, that don't meet reduction targets would buy credits from those who reduce output of the gases.

`Critical Stage'

``We are at a critical stage in the conversation on climate change, energy consumption and environmental protection,'' Ford CEO Alan Mulally said in a statement. ``We all recognize it is time for action.''

More than 20 corporations are members of the business- environmental partnership created in January, including General Electric Co., Lehman Brothers Holdings Inc., DuPont Co., Alcoa Inc., PepsiCo Inc., Dow Chemical Co., and Johnson & Johnson.

The companies have said they want a federal limit on greenhouse gases so they know how to proceed with their long- term investments. Some also say they will seek to profit by developing technologies that will help curb emissions or by otherwise participating in new market-based solutions to combat climate change.

The group's environmentalist members include the National Wildlife Federation, the Nature Conservancy, the National Resources Defense Council, the Pew Center on Global Climate Change and World Resources Institute.

Chrysler is being sold by Stuttgart, Germany-based DaimlerChrysler to Cerberus Capital Management LP.

U.S. shares of DaimlerChrysler rose 1 cent to $89.77 at 4:18 p.m. in New York Stock Exchange composite trading. Shares of Dearborn, Michigan-based Ford rose 32 cents to $9.28, while shares of Detroit-based GM rose $1.06 to $37.41

To contact the reporters on this story: Jeff Bennett in Southfield, Michigan, at jbennett17@bloomberg.net; Gopal Ratnam in Washington at gratnam1@bloomberg.net

Last Updated: June 27, 2007 16:21 EDT