PARIS (AP) – The world’s leading climate scientists, in their most powerful language ever used on the issue, said global warming is “very likely” man-made, according to a new report obtained Friday by The Associated Press.

The report provides what may be cold comfort in slightly reduced projections on rising temperatures and sea levels by the year 2100. But it is tempered by a flat pronouncement that global warming is essentially a runaway train that cannot be stopped for centuries.

“The observed widespread warming of the atmosphere and ocean, together with ice-mass loss, support the conclusion that it is extremely unlikely that global climate change of the past 50 years can be explained without external forcing, and very likely that is not due to known natural causes alone,” said the 20-page report.

Human-caused warming and rises in sea-level “would continue for centuries” because the process has already started, “even if greenhouse gas concentrations were to be stabilized,” said the 20-page report from the Intergovernmental Panel on Climate Change.

The report by a group of hundreds of scientists and representatives of 113 governments contains the most authoritative science on the issue.

The phrase “very likely” translates to a more than 90 percent certainty that global warming is caused by man.

What that means in layman’s language is “we have this nailed,” said top U.S. climate scientist Jerry Mahlman, who originated the percentage system.

It marked an escalation from the panel’s last report in 2001, which said warming was “likely” caused by human activity. There had been speculation that the participants might try to up the ante to “virtually certain” man causes global warming, which translates to 99 percent chance.

On sea levels, the report projects rises of 7-23 inches by the end of the century. That could be augmented by an additional 4-8 inches if recent surprising polar ice sheet melt continues.

The 2001 report projected a sea level rise of up to 35 inches.

Many scientists had warned that this was being too cautious and said sea level rise could be closer to 3 to 5 feet because of ice sheet melt.

But despite losing on that battle, scientists said the report is strong.

“There’s no question that the powerful language is intimately linked to the more powerful science,” said one of the study’s many co-authors, Andrew Weaver of the University of Victoria, who spoke by phone from Canada. He said the report was based on science that is rock-solid, peer-reviewed, conservative and consensus. “It’s very conservative. Scientists by their nature are skeptics.”

The scientists wrote the report, based on years of peer-reviewed research; government officials edited it with an eye toward the required unanimous approval by world governments. In the end, there was little debate on the strength of the wording about human activity most likely to blame.

“That is a big move. I hope it is a powerful statement,” said Jan Pretel, head of the department of climate change at the Czech Hydrometeorological Institute.

The panel quickly agreed Thursday on two of the most contentious issues: attributing global warming to man-made burning of fossil fuels and connecting it to a recent increase in stronger hurricanes.

Negotiations over a final third difficult issue – how much sea level rise is predicted by 2100 – went into the night Thursday with a deadline approaching for the report.

While critics call the panel overly alarmist, it is by nature relatively cautious because it relies on hundreds of scientists, including skeptics.

“I hope that policymakers will be quite convinced by this message,” said Riibeta Abeta, a delegate whose island nation Kiribati is threatened by rising seas. “The purpose is to get them moving.”

The Chinese delegation was resistant to strong wording on global warming, said Barbados delegate Leonard Fields and others. China has increasingly turned to fossil fuels for its huge and growing energy needs and it asked that an ambiguous footnote be added to the “very likely” statement.

The footnote reads: “Consideration of remaining uncertainty is based on current methodology,” according to an official who was at the negotiations but was sworn to secrecy.

Meanwhile, the U.S. government delegation was not one of the more vocal groups in the debate over whether warming is man-made, said other countries’ officials. And several attendees credited the head of the panel session, Susan Solomon, a top U.S. government climate scientist, with pushing through the agreement so quickly.

The Bush administration acknowledges that global warming is man-made and a problem that must be dealt with, Bush science adviser John Marburger has said. However, Bush continues to reject mandatory limits on so-called “greenhouse” gases, even as he acknowledges the existence of climate change.

But this is more than just a U.S. issue.

“What you’re trying to do is get the whole planet under the proverbial tent in how to deal with this, not just the rich countries,” Mahlman said Thursday. “I think we’re in a different kind of game now.”

The panel, created by the United Nations in 1988, releases its assessments every five or six years – although scientists have been observing aspects of climate change since as far back as the 1960s. The reports are released in phases, with this one being the first of four this year.

The next report is due in April and will discuss the effects of global warming.

But there are some elements of that in the current document.

The report says that global warming has made stronger hurricanes, including those on the Atlantic Ocean, such as Hurricane Katrina, according to Fields, the Barbados delegate, and others.

It also said an increase in hurricane and tropical cyclone strength since 1970 “more likely than not” can be attributed to man-made global warming. The scientists said global warming’s connection varies with storms in different parts of the world, but that the storms that strike the Americas are global warming-influenced.

That’s a contrast from the 2001 which said there was not enough evidence to make such a conclusion. And it conflicts with a November 2006 statement by the World Meteorological Organization, which helped found the IPCC. The meteorological group said it could not link past stronger storms to global warming.

Fields – of Barbados, a country in the path of many hurricanes – said the new wording was “very important.” He noted that insurance companies ê which look to science to calculate storm risk – “watch the language, too.”

Copy the Story Link