[News] Climate Warning as Siberia Melts

Fri Aug 12 12:09:26 EDT 2005

Climate warning as Siberia melts

http://www.newscientist.com/article/mg18725124.500.html
    * 11 August 2005
    * NewScientist.com news service
    * Fred Pearce

THE world's largest frozen peat bog is melting. An area stretching for a 
million square kilometres across the permafrost of western Siberia is 
turning into a mass of shallow lakes as the ground melts, according to 
Russian researchers just back from the region.

The sudden melting of a bog the size of France and Germany combined could 
unleash billions of tonnes of methane, a potent greenhouse gas, into the 
atmosphere.

The news of the dramatic transformation of one of the world's least visited 
landscapes comes from Sergei Kirpotin, a botanist at Tomsk State 
University, Russia, and Judith Marquand at the University of Oxford.

Kirpotin describes an "ecological landslide that is probably irreversible 
and is undoubtedly connected to climatic warming". He says that the entire 
western Siberian sub-Arctic region has begun to melt, and this "has all 
happened in the last three or four years".

What was until recently a featureless expanse of frozen peat is turning 
into a watery landscape of lakes, some more than a kilometre across. 
Kirpotin suspects that some unknown critical threshold has been crossed, 
triggering the melting.

Western Siberia has warmed faster than almost anywhere else on the planet, 
with an increase in average temperatures of some 3 °C in the last 40 years. 
The warming is believed to be a combination of man-made climate change, a 
cyclical change in atmospheric circulation known as the Arctic oscillation, 
plus feedbacks caused by melting ice, which exposes bare ground and ocean. 
These absorb more solar heat than white ice and snow.

Similar warming has also been taking place in Alaska: earlier this summer 
Jon Pelletier of the University of Arizona in Tucson reported a major 
expansion of lakes on the North Slope fringing the Arctic Ocean.

The findings from western Siberia follow a report two months ago that 
thousands of lakes in eastern Siberia have disappeared in the last 30 
years, also because of climate change (New Scientist, 11 June, p 16). This 
apparent contradiction arises because the two events represent opposite end 
of the same process, known as thermokarsk.

In this process, rising air temperatures first create "frost-heave", which 
turns the flat permafrost into a series of hollows and hummocks known as 
salsas. Then as the permafrost begins to melt, water collects on the 
surface, forming ponds that are prevented from draining away by the frozen 
bog beneath. The ponds coalesce into ever larger lakes until, finally, the 
last permafrost melts and the lakes drain away underground.

Siberia's peat bogs formed around 11,000 years ago at the end of the last 
ice age. Since then they have been generating methane, most of which has 
been trapped within the permafrost, and sometimes deeper in ice-like 
structures known as clathrates. Larry Smith of the University of 
California, Los Angeles, estimates that the west Siberian bog alone 
contains some 70 billion tonnes of methane, a quarter of all the methane 
stored on the land surface worldwide.

His colleague Karen Frey says if the bogs dry out as they warm, the methane 
will oxidise and escape into the air as carbon dioxide. But if the bogs 
remain wet, as is the case in western Siberia today, then the methane will 
be released straight into the atmosphere. Methane is 20 times as potent a 
greenhouse gas as carbon dioxide.

In May this year, Katey Walter of the University of Alaska Fairbanks told a 
meeting in Washington of the Arctic Research Consortium of the US that she 
had found methane hotspots in eastern Siberia, where the gas was bubbling 
from thawing permafrost so fast it was preventing the surface from 
freezing, even in the midst of winter.

An international research partnership known as the Global Carbon Project 
earlier this year identified melting permafrost as a major source of 
feedbacks that could accelerate climate change by releasing greenhouse 
gases into the atmosphere. "Several hundred billion tonnes of carbon could 
be released," said the project's chief scientist, Pep Canadell of the CSIRO 
Division of Marine and Atmospheric Research in Canberra, Australia.

Related Articles

    * <http://www.newscientist.com/article.ns?id=dn7644>G8 leaders agree 
global warming is urgent problem
    * http://www.newscientist.com/article.ns?id=dn7644
    * 08 July 2005
    * <http://www.newscientist.com/article.ns?id=dn6124>Peat bogs harbour 
carbon time bomb
    * http://www.newscientist.com/article.ns?id=dn6124
    * 07 July 2004
    * <http://www.newscientist.com/article.ns?id=mg18625034.700>Melting 
permafrost pulls plug on Arctic lakes
    * http://www.newscientist.com/article.ns?id=mg18625034.700
    * 11 June 2005

Weblinks

    * <http://www.globalcarbonproject.org/>Global Carbon Project
    * http://www.globalcarbonproject.org/
    * <http://www.ispe.arizona.edu/about/exec/pelletier.html>Jon Pelletier, 
University of Arizona
    * http://www.ispe.arizona.edu/about/exec/pelletier.html
    * <http://lena.sscnet.ucla.edu/>Larry Smith, UCLA
    * http://lena.sscnet.ucla.edu/

Printed on Fri Aug 12 17:08:09 BST 2005

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