(AP) -- Climate-change heavyweights U.N. chief Ban Ki-moon and Nobel prize winner Al Gore urged more than 500 business leaders on Sunday to lend their corporate muscle to reaching a global deal on reducing greenhouse gases.
The CEOs of PepsiCo, Nestle, BP and other major world businesses began meeting in Copenhagen, where politicians will gather in December to negotiate a new U.N.-brokered climate treaty.
Despite the global financial crisis, both Ban and Gore said there was no time for delay in hashing out the specifics of how to cut greenhouse gases that contribute to warming the planet.
"We have to do it this year. Not next year. This year," Gore said. "The clock is ticking, because Mother Nature does not do bailouts."
The three-day World Business Summit on Climate Change is a precursor to the negotiations to determine what will succeed the Kyoto climate treaty that expires in 2012.
"Continuing to pour trillions of dollars into fossil-fuel subsidies is like investing in subprime real estate," Ban said. "Our carbon-based infrastructure is like a toxic asset that threatens the portfolio of global goods, from public health to food security."
A new global warming treaty would build on the Kyoto treaty's mixed success in requiring that 37 industrialized nations reduce greenhouse gas emissions an average of 5 percent below 1990 levels by 2012.
Gore said any of the ambitious treaty goals being discussed will depend on CEOs working out greener ways of doing business and governments reining in unrestricted pollution.
"The business community and the leaders of the world must go together to safeguard the world," he told a forum that even drew Queen Margrethe of Denmark.
Xie Zhenhua, vice chairman of China's national development and reform commission, pledged to play "a positive and a constructive" role to reach a global climate treaty, and already is putting in place its climate plan for 2015 and beyond.
"During negotiations, developed countries always hope that a future China may do much better and greater efforts on addressing climate change issues," he said.
Rajendra K. Pachauri, head of the U.N. Intergovernmental Panel on Climate Change that shared the 2007 Nobel Peace Prize with Gore, said already "we are perhaps at the upper range" of predicted higher temperatures this century.
"We have a very short window of opportunity," he said. "If we want to limit temperature increase to about 2 degrees Celsius (3.6 degrees Fahrenheit), then emissions globally must peak by 2015."
About 300 anti-globalization activists marched Sunday toward the convention, heavily guarded by police. Some 40 teenage activists were handcuffed with plastic strips and detained after they were caught in woods nearby.
The police removed two water pistols from one of them; another was carried away by three officers.
Erik Rasmussen, the conference organizer, said business leaders are mulling specific and binding targets for reducing greenhouse gases within 10 years and 20 years that would be announced at the end of the conference.
Anders Eldrup, CEO of Danish state-controlled oil and gas group DONG Energy, said businesses face a big choice.
"There are two tracks being discussed now, one a tax on CO2 and a cap-and-trade," he said, leaning toward the carbon tax.
However, Connie Hedegaard, Denmark's climate minister, told The Associated Press the best solution is global limits on pollution blamed for global warming instead of a tax on carbon dioxide and other warming gases.
Hedegaard urged businesses to back such limits, called cap-and-trade, which require governments to issue pollution allowances, or permits, to businesses that could be traded.
"I would hope that they would sort of agree that some kind of cap and trade will be the most efficient tool to achieve what science tells us what we must achieve," she said. "A carbon tax - you can just pay that tax - but you must also have the caps so that you start innovating from there."
An emissions trading plan advanced in the U.S. Congress last week, increasing the likelihood that the full House of Representatives will for the first time address broad legislation to tackle climate change later this year.
Gore predicted it would pass the House, gain Senate approval and be signed into law by President Barack Obama.
The United States has said it is committed to reaching a deal in Copenhagen as long as other major polluters such as China and India do their part as well.
Associated Press Writer Jan M. Olsen contributed to this report.
©2009 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
Explore further: Pact with devil? California farmers use oil firms' water