The U.S. Chamber of Commerce has lost a handful of influential members over its opposition to climate change legislation being considered by Congress.

In recent weeks, Apple and three utilities -- Exelon, PNM Resources and PG&E -- said they will drop their membership in the Chamber, which represents more than 3 million businesses and organizations. Nike, which said it "fundamentally disagrees" with the group on climate change, will remain a member but resign from the Chamber's board.

"Nike believes U.S. businesses must advocate for aggressive climate change legislation," the athletic apparel maker said in a Sept. 30 statement. "We believe that on the issue of climate change, the Chamber has not represented the diversity of perspective held by the board of directors."

Exelon Chairman and CEO John W. Rowe supported the legislation in a speech to industry leaders and regulators last month, saying "the carbon-based free lunch is over."

"The price signal sent through a cap-and-trade system will drive low-carbon investments in the most inexpensive and efficient way possible," Mr. Rowe said at an American Council for an Energy Efficient Economy conference.

Another major industry group, the National Association of Manufacturers is losing Duke Energy as a member because of NAM's views on the legislation.

The recent defections from the Chamber come after one of its executives advocated putting the scientific findings of climate change on trial in much the same way evolution was examined during the 1926 Scopes Monkey Trial, where a teacher was tried for breaking a Tennessee law preventing the teaching of evolution.

The executive later said the reference was inappropriate, but the damage was done.

"We find it dismaying that the Chamber neglects the indisputable fact that a decisive majority of experts have said the data on global warming are compelling and point to a threat that cannot be ignored," PG&E Chairman, CEO and President Peter A. Darbee wrote in a Sept. 18 letter to Chamber President Thomas J. Donohue.

"Extreme rhetoric and obstructionist tactics seem to increasingly mark the Chamber's public stance on this issue," Mr. Darbee wrote. "These reflect neither the true range of views among members nor, in many cases, an honest view of the economic and environmental realities at hand."

The Chamber is used to taking criticism from labor unions and environmental groups, not from its own. Now a group of 43 investors representing more than $16 billion in assets is asking more Chamber members to distance themselves from the business lobbying group.

Last week, the investors sent letters to 14 companies asking them to make it clear that the Chamber does not reflect their views on climate change. The letter suggests a number of ways to do that, including dropping their membership, making a public statement to that effect or asking for a refund of the portion of their dues the Chamber uses to lobby on climate change.

The 14 companies targeted, including Alcoa, are members of the U.S. Climate Action Partnership or other groups backing efforts to curb global warming. The investors asking them to speak out are not exactly household names. They include Walden Asset Management, Green Century Capital Management, the Center for Political Accountability and about a dozen religious orders.

Walden Asset senior vice president Tim Smith said the opinions expressed in the letter "represent the concerns and view of many, many more investors." He believes it is important for the companies to make clear to shareholders and the media that the Chamber does not speak for them on climate change.

"The contradiction is stark. The companies recognize it. They recognize the Chamber is in one zone and they are in another," Mr. Smith said.

A Sept. 29 Chamber statement said the group "continues to support strong federal legislation and a binding international agreement to reduce carbon emissions and address climate change." The Chamber, as well as the manufacturers association, are concerned that the proposed legislation will raise energy costs and jeopardize jobs without requiring their foreign competitors to restrict greenhouse gas emissions.

U.S. Steel Chairman and CEO John P. Surma echoed those concerns last week at a coke industry conference in Pittsburgh, saying legislation should reflect the needs of steel and other energy-intensive, trade-sensitive industries. Mr. Surma said congressional proponents are basing their plan on Europe's cap-and-trade regimen, which he said has made utilities rich and the companies subjected to it poor.

The call for a Scopes trial notwithstanding, political and business leaders are unlikely to posture themselves as being in favor of greenhouse gas emissions. They are more likely to seek to win the public relations battle by overstating their environmental fervor.

Given the complexity of the issue, its economic and social implications, and other national priorities, what the issue calls for is less heat and more light.

Preferably light with a limited carbon footprint.

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