U.N. Says Growing Evidence of Warming

The U.N.'s climate panel warned on Monday that evidence was mounting each year of changes to Earth's weather system as it began talks on a new global warming report.

The world's paramount authority on the greenhouse effect, the Intergovernmental Panel on Climate Change (IPCC), will on Friday release the first volume of a comprehensive report on climate change, its impacts and ways to cope with the challenge.

The IPCC, co-winner of Nobel Peace Prize in 2007, gathers an army of specialists in physical science, agronomics, biology, economies and sociology. They have written four previous overviews in the panel's 25-year history.

"The scientific evidence of... climate change has strengthened year after year, leaving few uncertainties apart from the serious consequences," the panel's chairman Rajendra Pachauri said at the start of a gathering leading up to the report's release.

The panel on Friday will issue a main text on the physical science for climate change, plus a far smaller summary for policymakers, which is vetted by governments.

"I'm looking forward to working with you in the next four days to deliberate and approve (this summary) line by line," said Pachauri.

The volume is expected to paint a bleak picture of climate change in the coming decades.

The worst-case scenario, based on relentless emissions of heat-trapping fossil-fuel gases, predicts warming of more than triple the target set by vulnerable small-island states.

"Climate change is one of the greatest challenges of our time," said Thomas Stocker, co-chairman of the working group that has written the volume.

"Because this change threatens our primary resources, land and water -- in short, because it threatens our only home -- we must face this challenge."

He said the report was based on millions of measurements in the atmosphere, in the ocean, on land, in ice, and from space.

"I know of no document that has undergone this scrutiny and that has involved so many critical people who offered their insight and advice. This is what makes this report so unique," he said.

A draft document seen by Agence France Presse strengthens the IPCC's conviction in 2007 -- from 90 to 95 percent -- that humans are to blame for climate change.

The draft attributes an observed slowing in warming from 1998 to 2012 -- a phenomenon cited by skeptics as evidence that warming is not man-made -- to a temporary cooling cycle in the weather system and lower-than-expected solar activity.

Lena Ek, Sweden's environment minister, Monday praised "more than a thousand scientists working together, volunteering, to bring the world one scientific message on climate change, and also how it can tackle it."

Climate change had been sliding down the global agenda in recent years, partly as a result of the near-fiasco of the 2009 Copenhagen Summit, and partly because the global financial crisis has caused a reordering of priorities in many nations.

Non-governmental organisations pleaded with governments to revive the sense of urgency.

"This report demonstrates the urgent action needed to stop climate change in its tracks by committing to rapidly reducing global carbon emissions," said Alison Doig of Christian Aid, an international development charity.

"There is still time to prevent the worst effects, but our window of opportunity is closing rapidly and it's the world's poorest people who will suffer the most from our inaction."

Greenpeace climate change campaigner Stephanie Tunmore blamed lobbying by the energy sector for preventing tougher action against carbon emissions.

"It's like being in a car hurtling in the wrong direction with governments arguing about the seating arrangements and the fossil-fuel industry jamming the throttle open," she said.