Siberia's peat bogs

Villain or victim?

 
Last Updated: Sunday 07 June 2015

-- there is real bad news on the global warming front. Stealthily-rising temperature has taken its toll, now, on Siberia's wetlands. They lay frozen for millennia, until now. Receding glaciers or ice-cover are already legion; these no longer qualify as good copy. But what's happening in Siberia has serious ecological consequences. For, buried beneath the permanently frozen subsoil of the western Siberian lowland are billions of tonnes of methane, a potent greenhouse gas. Scientists, for long, have considered the vast frozen peat bogs (wet spongy ground of decomposing vegetation) in Siberia a good carbon sink. It is estimated that about 70 billion tonnes of methane gas -- a quarter of the world's entire methane reserves -- is locked up beneath the western Siberian soil.

But carbon sink it no longer is. A team of Russian scientists on an expedition have recently discovered that this vast expanse of frozen land is slowly turning wet and soggy. They spotted a mass of shallow lakes -- many of them a kilometre across. They fear the methane will bubble out of the peat land, if the ice were to melt. Such release will drastically add to the already-burgeoning atmospheric methane load, hastening the global warming process. They dub the phenomenon they studied as an "ecological landslide". It seems to have commenced three to four years ago.

The western Siberian lowlands cover more than one million square kilometres -- the size of France and Germany combined. There are more than 10,000 peat bogs filled with decaying plant material, including sphagnum moss, lichen and tree trunks. Their depth ranges from less than 1 metre to 10 metres. For almost 11,000 years, a chilly climate ensured the decaying material never fully decomposed. Now, rising temperature is dramatically changing things. If only one-fourth of methane sequestered in this soil were to belch out, it would be catastrophic. Methane is 20 times as potent a greenhouse gas as carbon dioxide.

Typically, there are attempts to portray what is happening in Western Siberia as 'natural'. This is far from true. There is evidence Siberia has warmed faster than any place in the world; average temperature here has gone up by about 3 degrees Celsius in the last 40 years due to climate change associated with anthropogenic activities.

So: Is the Siberian bog a villain? Or is it a victim?

Subscribe to Weekly Newsletter :

Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.