Iconic computer and mobile-device maker Apple, Inc. has quit the U.S. Chamber of Commerce over the Chamber’s position on climate-change regulation, becoming the highest-profile member to leave the premier lobbying voice for the nation’s business community.

Apple is the latest in a string of companies to leave the chamber over the greenhouse-gas regulation debate. It’s a sign of the fractures to come between businesses over a debate that will deeply affect how we use energy, and thus, nearly every corner of the U.S. economy.

Catherine Novelli, the computer company’s vice president for worldwide government affairs wrote a letter to Chamber President Thomas Donohue expressing her company’s displeasure with the Chamber’s position and resigning effective immediately.

"Apple supports regulating greenhouse-gas emissions, and it is frustrating to find the Chamber at odds with us in this effort," she wrote. Apple has in the past faced criticism from environmentalists over some of its environmental practices, but has more recently been trying to project a greener image.

The Chamber has opposed the possibility of the Environmental Protection Agency regulating greenhouse gasses under the Clean Air Act. And it has also taken a position that legislation that has passed the U.S. House of Representatives to restrict greenhouse-gas emissions is flawed because it doesn’t require other countries to act and it doesn’t invest enough in green technology, Donohue has said.

The legislation would set limits on carbon dioxide emissions and force companies that exceed those limits to buy carbon credits from other companies that don’t pollute as much. The credits would be bought and sold in a market similar to a commodities exchange.

At the same time, the EPA, acting on a Supreme Court ruling that found carbon dioxide was a pollutant under the Clean Air Act, has started working on regulations of its own to limit emissions.

President Barack Obama has said he would prefer legislation to regulation. But he favors cutting emissions and is under international pressure to make the United States a leader once again in fighting climate change. Cutting greenhouse-gas emissions was one of his top campaign promises, along with reforming the nation’s health care system.

The Chamber’s sometimes strident opposition, especially to EPA regulation—one official called for a “Scopes Monkey Trial” on global-warming science—has infuriated several companies that support global-warming legislation, leading some, like Apple, to leave the Chamber.

Last week, John Rowe, CEO of Exelon, one of the nation’s largest electric utilities, said his company would quit the Chamber—which has over 3 million members. Rowe’s Chicago-based company is the nation’s largest provider of nuclear power, and a large portion of its electricity also comes from natural-gas plants. Natural gas is the cleanest-burning of the fossil fuels, and nuclear power doesn’t emit any greenhouse gasses. So it’s not as much of a stretch as it may seem for Exelon to support a lower-carbon society. It could conceivably be a winner in such a society—able to trade emissions permits for a profit with heavier greenhouse-gas emitters.

Exelon wasn’t the first of the big utilities to depart the Chamber.

PG&E Corp. CEO Peter Darbee last month wrote to Donahue criticizing the Chamber’s recent positions on climate change and announcing that his company was leaving the organization. “Extreme rhetoric and obstructionist tactics seem increasingly to mark the Chamber’s public stance on this issue,” Darbee wrote.