“But the corporate message hasn’t sunk through,” he said. “It’s a murmur — many voices are saying the same thing, but because it’s not being said together, it doesn’t come through clearly.”

He called on the companies to “make the murmur into a message” that would grab his colleagues’ attention.

Whitehouse and Rep. Henry Waxman (D-Calif.), his co-chairman on the Bicameral Task Force on Climate Change, heard from five companies that touted their efforts to curb company emissions and harden their operations against climate change. The briefing marked the first anniversary of a “climate declaration” signed by 750 companies calling for climate legislation.

Letitia Webster, global director of corporate sustainability for outdoor apparel company VF Corp., said climate change topped its customers’ list of concerns. A major consumer of cotton, VF is taking steps to improve the sustainability of the supply chain, she said. She also made a pitch for carbon legislation and a permanent renewable energy tax credit.

Rob Olson, chief financial officer of Ikea US, announced the company’s investment in a new Hoopeston, Ill., wind farm. The company has a goal of relying on renewable energy for two-thirds of its power, he said.

Colin Dyer, president and CEO of commercial real estate company Jones Lang LaSalle, discussed ways to improve building efficiency, including through government action. Kevin Rabinovich, director of global sustainability for Mars Inc., the chocolate maker, said his company had mapped the genome of cocoa and released it into the public domain in hopes of finding more drought-resistant strains of the vital crop. Amy Hargroves, director of corporate responsibility and sustainability for Sprint Communications Inc., made a pitch for good corporate citizenship.

But Hargroves, whose company is based in Kansas, said that climate change is rarely a topic raised during meetings about the company’s sustainability practices.

“We’ve tried to change the dialogue a little bit away from the climate issue because it has so much baggage on it, and instead just talk about the business benefits,” she said.

But Whitehouse said that internal efforts by companies will only go so far toward addressing warming.

“It doesn’t support the next step, which is: How do you break through this little ring of denial that a very small subset of the corporate community has erected around Washington, D.C., very inconsistently with the views and experience of the great majority of the corporate community?” he said.

Whitehouse has said that EPA’s existing power plant guidance that will be proposed later this spring may be a turning point for corporate interest in a carbon price. Faced with a new obligation to limit emissions, he argues, large utilities will demand economywide legislation that would share responsibility.

But while the agency has said little about the proposal it must release early in June, officials have assured stakeholders that it will be cost-effective and will not require today’s power fleet to retrofit with carbon capture and sequestration technology.

The rule is currently undergoing interagency review at the White House.