Major global warming report

The Eiffel Tower's 20,000 flashing light bulbs will go dark for five minutes on Thursday evening, hours before scientists and officials publish a long-awaited report about global warming.

The blackout comes at the urging of environmental activists seeking to call attention to energy waste -- and just hours before world scientists unveil a major report on Friday warning that the planet will keep getting warmer and presenting new evidence of humanity's role in climate change.

The Intergovernmental Panel on Climate Change will release a report laying out policy proposals for governments based on the latest research on global warming.

The top U.N. official for the environment asked Secretary-General Ban Ki-moon on Tuesday to convene an emergency summit of world leaders aimed at breaking a deadlock over cutting greenhouse gases.

The impetus for such a world summit is U.S. President George W. Bush's acknowledgment in his Jan. 24 State of the Union speech that climate change needs to be dealt with, and the EU's Jan. 10 proposals for a new European energy policy that stresses the need to slash carbon emissions blamed for global warming, U.N. environment program spokesman Nick Nuttall said.

"There's a lot of momentum that has being building," Nuttall said. "We have a window of opportunity."

Nuttall said the summit could be held between July and December.

The second day of the Paris talks wound down Tuesday evening more or less on schedule, according to officials at UNESCO, the conference's host.

There was little sign of the late-night wrangling among countries that marked previous reports. The report must be unanimously approved by bureaucrats from more than 100 governments who can challenge the scientists' wording.

"The government people determine how things are said, but we (the scientists) determine what is said," said Kevin Trenberth, a lead author of the report and director of climate analysis at the U.S. National Center for Atmospheric Research in Colorado.

The end result is a cautious document, many scientists say.

One Russian participant said Tuesday that the discussions he observed were more procedural than political.

Another observer who has taken part in several such conferences, Stephanie Tunmore of Greenpeace, said, "So far we're running on timetable. But who knows, we've got two more days. If there's any panic, it will be Wednesday night when they realize they've only got a few hours left."

An early draft of the report being released in Paris suggests it will contain stronger evidence of the human role in climate change and more specific predictions of rising temperatures and sea levels this century.

The report "won't change our scientific basis, but it will make our jobs easier," Steve Sawyer, of Greenpeace, said Tuesday. "It is an important and powerful new tool in public debate and policy debate."

Environmental groups have long urged governments and consumers to rely more on renewable energy sources such as solar and wind power instead of greenhouse gas-emitting ones like coal and oil. Greenhouse gases are considered a key culprit of rising global temperatures.