Thaw will speed warming
Special report: climate change
* * * *
Warming hits 'tipping point'
Siberia feels the heat It's a frozen peat bog the size of France and
Germany combined, contains billions of tonnes of greenhouse gas and, for
the first time since the ice age, it is melting
Ian Sample, science correspondent
Thursday August 11, 2005
A vast expanse of western Sibera is undergoing an unprecedented thaw
that could dramatically increase the rate of global warming, climate
scientists warn today.
Researchers who have recently returned from the region found that an
area of permafrost spanning a million square kilometres - the size of
France and Germany combined - has started to melt for the first time
since it formed 11,000 years ago at the end of the last ice age.
The area, which covers the entire sub-Arctic region of western Siberia,
is the world's largest frozen peat bog and scientists fear that as it
thaws, it will release billions of tonnes of methane, a greenhouse gas
20 times more potent than carbon dioxide, into the atmosphere.
It is a scenario climate scientists have feared since first identifying
"tipping points" - delicate thresholds where a slight rise in the
Earth's temperature can cause a dramatic change in the environment that
itself triggers a far greater increase in global temperatures.
The discovery was made by Sergei Kirpotin at Tomsk State University in
western Siberia and Judith Marquand at Oxford University and is reported
in New Scientist today.
The researchers found that what was until recently a barren expanse of
frozen peat is turning into a broken landscape of mud and lakes, some
more than a kilometre across.
Dr Kirpotin told the magazine the situation was an "ecological landslide
that is probably irreversible and is undoubtedly connected to climatic
warming". He added that the thaw had probably begun in the past three or
Climate scientists yesterday reacted with alarm to the finding, and
warned that predictions of future global temperatures would have to be
"When you start messing around with these natural systems, you can end
up in situations where it's unstoppable. There are no brakes you can
apply," said David Viner, a senior scientist at the Climatic Research
Unit at the University of East Anglia.
"This is a big deal because you can't put the permafrost back once it's
gone. The causal effect is human activity and it will ramp up
temperatures even more than our emissions are doing."
In its last major report in 2001, the intergovernmental panel on climate
change predicted a rise in global temperatures of 1.4C-5.8C between 1990
and 2100, but the estimate only takes account of global warming driven
by known greenhouse gas emissions.
"These positive feedbacks with landmasses weren't known about then. They
had no idea how much they would add to global warming," said Dr Viner.
Western Siberia is heating up faster than anywhere else in the world,
having experienced a rise of some 3C in the past 40 years. Scientists
are particularly concerned about the permafrost, because as it thaws, it
reveals bare ground which warms up more quickly than ice and snow, and
so accelerates the rate at which the permafrost thaws.
Siberia's peat bogs have been producing methane since they formed at the
end of the last ice age, but most of the gas had been trapped in the
permafrost. According to Larry Smith, a hydrologist at the University of
California, Los Angeles, the west Siberian peat bog could hold some 70bn
tonnes of methane, a quarter of all of the methane stored in the ground
around the world.
The permafrost is likely to take many decades at least to thaw, so the
methane locked within it will not be released into the atmosphere in one
burst, said Stephen Sitch, a climate scientist at the Met Office's
Hadley Centre in Exeter.
But calculations by Dr Sitch and his colleagues show that even if
methane seeped from the permafrost over the next 100 years, it would add
around 700m tonnes of carbon into the atmosphere each year, roughly the
same amount that is released annually from the world's wetlands and
It would effectively double atmospheric levels of the gas, leading to a
10% to 25% increase in global warming, he said.
Tony Juniper, director of Friends of the Earth, said the finding was a
stark message to politicians to take concerted action on climate change.
"We knew at some point we'd get these feedbacks happening that
exacerbate global warming, but this could lead to a massive injection of
"If we don't take action very soon, we could unleash runaway global
warming that will be beyond our control and it will lead to social,
economic and environmental devastation worldwide," he said. "There's
still time to take action, but not much.
"The assumption has been that we wouldn't see these kinds of changes
until the world is a little warmer, but this suggests we're running out
In May this year, another group of researchers reported signs that
global warming was damaging the permafrost. Katey Walter of the
University of Alaska, Fairbanks, told a meeting of the Arctic Research
Consortium of the US that her team had found methane hotspots in eastern
Siberia. At the hotspots, methane was bubbling to the surface of the
permafrost so quickly that it was preventing the surface from freezing over.
Last month, some of the world's worst air polluters, including the US
and Australia, announced a partnership to cut greenhouse gas emissions
through the use of new technologies.
The deal came after Tony Blair struggled at the G8 summit to get the US
president, George Bush, to commit to any concerted action on climate
change and has been heavily criticised for setting no targets for
reductions in greenhouse gas emissions.
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