"The strong message (from the report) is that it's possible to stabilize greenhouse gas emissions at the level where severe climatic change can be avoided," said Lars Nilsson, a delegate from Sweden.
Two previous IPCC reports this year warned that unabated greenhouse gas emissions could drive global temperatures up as much as 11 degrees by 2100. Even a 3.6-degree rise could subject up to 2 billion people to water shortages by 2050 and threaten extinction for 20 percent to 30 percent of the world's species, the IPCC said.
The third report, which was expected to be formally announced later in the morning, makes clear the world must quickly embrace a basket of technological options -- both already available and developing -- just to keep the temperature rise to 3.6 degrees Fahrenheit.
Much of this week's debate has centered around how much it will cost to adopt greener policies.
China is facing increasing international pressure as its economy expands -- it posted 11.1 percent growth in the first quarter -- and it pumps increasing amounts of greenhouse gases into the atmosphere.
At this week's meeting, Beijing campaigned for wording that would clearly blame the top industrialized countries in North America and Europe for global warming and give them the responsibility for solving it, rather than latecomers like China and India, delegates said. (Watch how China is on track to being the world's top polluter )
Chinese delegates did not discuss their positions publicly, but environmental activists suggested Thursday that China was being unfairly targeted, saying it was making strong efforts to improve energy efficiency and rein in emissions.
Stephan Singer, of the conservation group WWF International, said China had a worthy target of increasing energy efficiency by 20 percent from 2006 to 2010.
"It's a very ambitious target and I would wish many industrialized countries would have the same target," Singer told reporters.
The U.S. remained surprisingly quiet on most issues at the meeting, but some delegates said it appeared to be content letting China take the lead. However, the U.S. delegation was vocal over the role nuclear power could play in efforts to reduce greenhouse gases. European nations reminded policymakers not to forget the security risks that could be associated with that.
The world needs to divert substantially from today's main energy sources within a few decades to limit centuries of rising temperatures and seas driven by the buildup of heat-trapping emissions in the air, the top body studying climate change has concluded.
In an all-night session capping four days of talks in Bangkok, economists, scientists and government officials from more than 100 countries agreed early Friday on the last sections of a report outlining ways to limit such emissions, led by carbon dioxide, an unavoidable byproduct of burning coal and oil.
The final report, from the Intergovernmental Panel on Climate Change, said prompt slowing of emissions could set the stage later in the century for stabilization of the concentration of carbon