"If you're looking for proof climate change is happening, stop looking for receding glaciers and start looking at the changing marketplace," said Andrew Hoffman of the University of Michigan, who wrote the report.

Of 31 major corporations that completed a 100-question survey, 90 percent expect the US government to set standards for greenhouse gas emissions imminently; 67 percent believe those laws will go into effect between 2010 and 2015.

There are at least seven proposals in the US Senate to limit these emissions, which contribute to global warming by trapping the sun's heat like the glass walls of a greenhouse.

Eileen Claussen, president of the Pew climate change center, said a federal law on greenhouse gas emissions was possible in 2008, but only if certain changes occur.

"I think you may have to have turnover in the House and you may have to have a presidential candidate on the Republican side who wants to do something about climate change," Claussen said. She added that 2010 might be a more likely year for laws on emissions.

'A SEAT AT THE TABLE'

The Bush administration has a goal of cutting greenhouse gas intensity -- the ratio of emissions to economic output -- by 18 percent by 2012, compared to 2002. This amounts to a goal of emissions growth, Claussen said. She characterized the administration's stance as "too little, too late."

While some companies still are engaged in the scientific debate over global warming, all see a business reason to develop strategies to deal with climate change, Hoffman said.

In the report, six case studies of major corporations are meant to be a guide for other companies, he said.

At aluminum-maker Alcoa, for example, emissions are 30 percent lower now than in 1990, and the company plans to use at least 50 percent recycled metal in its production processes, said Alcoa's Lee Califf, who was also at the briefing.

Chemical giant DuPont, which is heavily dependent on the fossil fuels that emit greenhouse gases, had global energy consumption that was 7 percent lower in 2005 than in 1990, according to Edwin Mongan, the firm's director of energy and environment.

Randy Armstrong of Shell Oil Company stressed the need to be involved as new policies are crafted, noting that Shell's own emissions and the emissions from their products make up over 3 percent of the world total.

"As a large energy company ... we find ourselves in the middle of the greenhouse gas debate whether we like to or not," Armstrong said. "As this concern on this policy changes, our industry in the next 50 years may face radical changes. therefore we would really like a seat at the table."

The report is available online at www.pewclimate.org.