General Motors is joining the United States Climate Action Partnership, becoming the first automaker to support the group’s call for action to address climate change.

“GM is very pleased to join USCAP in proactively addressing the concerns posed by climate change,” said Rick Wagoner, chairman and CEO of General Motors. “The key as we see it is energy diversity -? being able to offer our customers vehicles that can be powered by many different energy sources and advanced propulsion systems to help displace petroleum and reduce greenhouse gas emissions.”

In testimony before Congress in March, Wagoner said, “Now is the time for a new, more comprehensive and forward-looking national strategy that ensures we’re working on the right things that will really make a difference in reducing oil consumption and CO2 emissions.”

Also, in the same testimony Wagoner said GM is willing to engage in discussions on carbon constraints on the U.S. economy as part of such a broader climate change strategy. GM’s position is consistent with USCAP’s strong commitment toward an economy-wide policy and legislative framework that would include a mandatory, flexible cap-and-trade program.

USCAP is on a roll, having doubled its membership to include AIG, Alcan, Boston Scientific, ConocoPhillips, Deere & Company, The Dow Chemical Company, General Motors Corp., Johnson & Johnson, Marsh, PepsiCo, Shell Oil and Siemens, along with The Nature Conservancy and the National Wildlife Federation.

With its new members, USCAP companies now have total revenues of $1.7 trillion, a collective workforce of more than 2 million and operations in all 50 states. The non-governmental organizations have more than two million members worldwide.

The founding members of USCAP include Alcoa, BP America, Caterpillar, Duke Energy, DuPont, FPL Group, Inc., General Electric, PG&E, and PNM Resources, along with four leading non-governmental organizations – Environmental Defense, Natural Resources Defense Council, Pew Center on Global Climate Change and World Resources Institute.

“With this lineup of companies and environmental groups endorsing it, a carbon cap is clearly the consensus solution to climate change,” said Fred Krupp, president of Environmental Defense.  “With cap and trade, we’ve found the center. Environmental groups and businesses can embrace it because it guarantees results for the climate while freeing companies to hunt for innovative, least-cost ways to lower emissions.”