General Electric Co., Canon Inc. and Nike Inc. lead consumer products businesses in efforts to measure and reduce carbon dioxide emissions, while Apple Computer Inc., EBay Inc. and Wendy's International Inc. have done little to address global warming, according to a study.

The comparison of 56 consumer products companies used publicly available information to rate them on emissions measurement, reduction, regulatory advocacy and disclosure, said Wood Turner, author of the study.

"We wanted to pull back the curtain on companies that aren't assessing the damage they're causing," Turner, director of non-profit Climate Counts, said in an interview. "We're a proxy for the average consumer."

The study didn't consider the amount of carbon emissions for each company in its ratings.

Climate Counts, founded by yogurt-maker Stonyfield Farm Inc., selected the top brands in each of eight consumer-product categories in the U.S. and England, including apparel, electronics, media, food services and household products.

The group contacted each of the companies in the study to inform them of the results of their searches and offer an opportunity to respond, Turner said.

Canon, the Tokyo-based camera and copier maker, scored highest in the group with a 77 out of 100. Nike, the maker of shoes and athletic clothing, earned 73, London-based Unilever LLC was rated 71, Group Danone's Stonyfield Farm had 63, and GE 61.

"The fact that the highest score was 77 indicates that there's a lot of work to be done and a lot of room for improvement," Turner said. He scored each of the companies himself based on a set of 22 climate and corporate-performance criteria.

Of the 56 companies in the study, 22 were given a score of 2 or less, showing that they have done little or nothing to address climate change. Apple had the lowest for an electronics company with a score of 2, same as EBay, while Wendy's, CBS Corp. and Amazon.com Inc. each had zeros.

Last year, EBay said it hired a consultant to determine the company's greenhouse gas emissions and this year committed $2 million to offset those emissions, said Hani Durzy, a spokesman for the company said.

"We are actively engaged in efforts to reduce power consumption in our office spaces as well as energy reduction at our data centers," Durzy said. The company may add solar power and fuel cells to its new headquarters, he said.

Steve Dowling, a spokesman for Apple, didn't respond to e-mails seeking comment on its climate efforts. Bob Bertini, a Wendy's spokesman, didn't return a message left on his voicemail.

The U.S. is the world's largest emitter of greenhouse gasses, contributing a quarter of the pollution that scientists say causes global warming. The Bush administration has rejected as too costly attempts to mandate emission cuts, instead touting voluntary measures.