The head of the U.S. Chamber of Commerce on Tuesday appeared to take a jab at Apple Inc. (AAPL) and Chief Executive Steve Jobs for defecting from the business organization in a dispute over climate-change policy.

"It is unfortunate that your company didn't take the time to understand the Chamber's position on climate and forfeited the opportunity to advance a 21st century approach to climate change," U.S. Chamber of Commerce Chief Executive Tom Donohue wrote in a letter to the Apple chief executive. He said that the business group is committed to the environment but also to preserving the competitiveness of American business.

The largest U.S. trade association is mounting a public campaign to explain its position following a series of high-profile defections. In recent weeks, Nike Inc. (NKE), PG&E Corp. (PCG) and Exelon Corp. (EXC) are among those who have parted ways with the U.S. Chamber of Commerce over its opposition to climate legislation in the U.S. Congress.

"While we do support legislation to address climate change, we oppose legislation such as the Waxman-Markey bill that numerous studies show will cause Americans to lose their jobs and shift greenhouse gas emissions overseas, negating potential climate benefits," Donohue wrote. He said that the business group was focused on innovation and technology to combat climate change.

"It is a shame that Apple will not be part of our efforts," he wrote.

Apple could not immediately be reached for comment.

- By Siobhan Hughes, Dow Jones Newswires; 202-862-6654; Siobhan.Hughes@dowjones.com