Panel: Global Warming Caused By Humans

Officials from 113 countries agreed Thursday that a much-awaited international report will say that global warming was "very likely" caused by human activity, delegates to a climate change conference said.

Dozens of scientists and bureaucrats are editing the new report by the Intergovernmental Panel on Climate Change in closed-door meetings in Paris. Their report, which must be unanimously approved, is to be released Friday.

Two participants, speaking on condition of anonymity because the meetings are confidential, said the group approved the term "very likely" in Thursday's sessions. That means they agree that there is a 90 percent chance that global warming is caused by humans.

The last report, in 2001, said global warming was "likely" caused by human activity. There had been speculation that the participants might try to change the wording this time to "virtually certain," which means a 99 percent chance.

The report is considered an authoritative document that could influence government and industrial policy worldwide.

"Very likely" means it is at least 90 percent certain that climate change is caused by humans burning fossil fuels, and will result in a temperature increase of between 2.5-10.4 F by the year 2100.

Some participants apparently had wanted to change that wording to "virtually certain," which connotes a 99 percent likelihood.

Scientists are trying to incorporate concerns that their early drafts underestimate how much the sea will rise by 2100 because they cannot predict how much ice will melt from Greenland and Antarctica.

In early drafts, scientists predicted a sea level rise of no more than 23 inches by 2100, but that does not include the ice sheet melts.

Also, for the first time, the climate panel says stronger hurricanes and cyclones since 1970 are "more likely than not" linked to global warming, according to a draft. That could change, however, since the issue is hotly debated in scientific circles.

One participant, who asked not to be identified, said there was a noticeable change in the U.S. delegation, which some accused of hanging up the 2001 talks: "The U.S. is much more constructive."

In the same way as the United States took a long time to accept the realities of global warming and its human causes, the Bush administration is now stressing a very different approach from most countries on how to respond, reports CBS News correspondent Mark Phillips. One idea Washington is pushing is literally "pie in the sky."

The U.S. is funding a study to see if millions of reflective plates, launched into space and positioned between the Earth and the sun, could reflect enough energy away to limit the warming. It's a giant space sunscreen that, even the man studying it says, is a hugely expensive, desperate idea.

"What kind of a planet is this where you have to rely on the high technology fix. You have to go to the heart of the problem and reduce the greenhouse gases," says researcher Roger Angel of the University of Arizona.

The study traces global temperatures and so-called greenhouse gases going back thousands of years. It shows a gradual variation until the Industrial Revolution begins, when fossil fuel use skyrockets, as do temperatures, reports Phillips, who obtained an early version last week.

"As we add to those gases, we are just doing the same thing as putting another blanket on our bed at night," said Sir David King, British chief government scientific adviser. "The consequences are that you get warmer, and that is as simple as it is."

While this report presents the grim realities of climate change in stark terms, reports Phillips, it is not a doomsday scenario. There are responses - scientific, economic, political — that can help limit the damage and help the world react. Government advisers like King say solutions are already available. Among them: limiting emissions, hybrid cars, energy-efficient homes, alternative power sources and less travel.

During his State of the Union address last month, President Bush called for American imports to be cut by the equivalent of 75 percent of the oil coming from the Middle East.

In a subsequent a speech, Mr. Bush said he would seek $1.6 billion in funding over the next decade for research into alternative energy.

Former U.S. Sen. Timothy E. Wirth, a Colorado Democrat who was a former U.S. chief negotiator on the Kyoto Protocol, noted that the remarks were short on specifics, but that Mr. Bush was "understanding finally that this is a serious issue that the U.S. has to address."

Wirth added that the U.S. needed to provide leadership, but said it would be hard for Mr. Bush to do that.

"We will wait for John McCain or Hillary Clinton ... or somebody who will be in a very different position in 2009," he said, referring to the two senators who are considered the front-runners for the Republican and Democratic parties in the 2008 election.

Two private advocacy groups told a congressional hearing Tuesday that climate scientists at seven government agencies say they have been subjected to political pressure aimed at downplaying the threat of global warming.

The groups presented a survey that shows two in five of the 279 climate scientists who responded to a questionnaire complained that some of their scientific papers had been edited in a way that changed their meaning. Nearly half of the 279 said in response to another question that at some point they had been told to delete reference to "global warming" or "climate change" from a report.