That could mean everything from putting on a sweater rather than turning up the heat to buying a hybrid car, choosing a house on a public transportation line or hanging the laundry out to dry rather than throwing it in a clothes dryer.

"It does require lifestyle changes but not any sacrifices," insisted Jayant Sathaya, a senior energy technology scientist at the University of California at Berkeley and one of the report's authors.

He predicted the document would help guide the creation of emissions reduction policies around the world.

"Absolutely this will drive change," he said. "If we can convince everybody they should always keep climate mitigation in their minds in whatever decisions they make, we will be a long way toward achieving the goal."

The report follows two earlier UN climate statements this year. The first concluded that human activity, particularly the burning of fossil fuels, is almost certainly driving global warming, and the second laid out expected effects of climate change, including more severe and erratic weather, rising sea level, increasing flooding and droughts, species extinctions and changes in agricultural production.

The latest report warns that failure to take quick action to cut greenhouse gas emissions could lead to concentrations of the gases in the atmosphere more than doubling from the current 425 parts per million by 2100, raising worldwide average temperatures as much as 11 degrees. A recent European study suggests that if countries fail to stem climate change quickly they could eventually spend between 5 and 20 percent of their income each year trying to combat its effects.

"If we continue doing what we are doing now, we are in deep trouble," warned Ogunlade Davidson, a co-chair of the working group that produced the new report. But "this report is all about solutions," he said.

"The IPCC has delivered a road map for keeping the planet safe. Now it's the turn of politicians to do more than pay just lip service," added Hans Verolme, director of the World Wildlife Fund's climate change program.

Scientists and government delegates in Bangkok said they hoped the report would serve as a basis for climate discussions at the upcoming Group of Eight summit of leading developed countries in June in Germany and at a planned UN climate summit in Bali, Indonesia, in December.