VALENCIA, Spain (AFP) — Less than three weeks before a crucial conference on climate change, UN experts agreed Friday on a draft report that warns global warming may have far-reaching and irreversible consequences.
The report by the Intergovernmental Panel on Climate Change (IPCC) is designed to guide policymakers for the next five years.
Delegates to the Nobel-winning scientific authority agreed the draft after night-long negotiations, chief French delegate Marc Gillet told AFP.
Human activities "could lead to abrupt or irreversible climate changes and impacts," the agreed text said.
The report will be officially adopted on Saturday, followed by a press conference attended by United Nations chief Ban Ki-moon.
It summarises three massive documents issued this year covering the evidence for climate change; the present and possible future impacts of it; and the options for tackling the peril.
After Saturday, attention shifts to a key meeting in Bali, Indonesia, where governments must set down a "roadmap" for negotiations culminating in a deal to slash carbon emissions and help developing nations cope with climate change.
The IPCC experts agreed that the rise in Earth's temperature observed in the past few decades was principally due to human causes, not natural ones, as "climate sceptics" often aver.
The impacts of climate change are already visible, in the form of retreating glaciers and snow loss in alpine regions, thinning Arctic summer sea ice and thawing permafrost, according to the three IPCC reports issued earlier this year.
But sometimes sharp disagreement emerged during the five days of negotiations in Valencia to hammer out the summary, even though the main findings remained untouched.
US delegates in particular said references to "irreversible" climate change and impacts were imprecise.
They argued, for example, that the melting of glaciers or ice sheets -- which could raise ocean levels by several meters (a dozen feet) -- was not "irreversible" as ice could eventually reform.
"But we are not dealing with geological time scales of tens of thousands of years," said one delegate, irked by this reasoning. "We are talking about dire consequences to humans and the environment in the coming decades."
By 2100, global average surface temperatures could rise by between 1.1 C (1.98 F) and 6.4 C (11.52 F) compared to 1980-99 levels, while sea levels will rise by between 18 and 59 centimetres (7.2 and 23.2 inches), according to the IPCC's forecast.
Heatwaves, rainstorms, drought, tropical cyclones and surges in sea level are among the events expected to become more frequent, more widespread and/or more intense this century.
As a result, water shortages, hunger, flooding and damage to homes will be a heightened threat.
"All countries" will be affected, according to the IPCC. Those bearing the brunt, though, will be poor countries which incidentally bear the least responsibility for creating the problem.
Green groups applauded the provisional report, saying it hiked pressure on world leaders to curb greenhouse gases.
"The result appears to be much better than we had expected going into the meeting," said Stephanie Tunmore of Greenpeace, which along with the WWF is an official observer at IPCC meetings.
"It could be a groundbreaking document to pave the way for deep emissions cuts by developed countries," said WWF's Stephan Singer.
Belgian IPCC delegate Jean-Pascal van Ypersele said his concerns that the synthesis would only be a "cut-and-paste" rather than a coherent summary proved unfounded.
He pointed to a draft section on "key vulnerabilities" that distilled the main reasons for concern about global warming.
Despite sharp challenges, especially from the US, the text remained intact, making "the problems more prominent," he said.
The IPCC won this year's Nobel Peace Prize alongside climate campaigner and former US vice president Al Gore.
The December 3-14 conference in Bali aims at deepening and accelerating cuts in greenhouse-gas pollution after 2012, when current pledges under the UN's Kyoto Protocol expire.
There is now broad agreement on the amplifying scale of the problem, but countries remain sharply divided on how to tackle it, fearing economic costs and loss of competitive advantage.
Copyright © 2013 AFP. All rights reserved. More »