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Snippets

Peat bogs and End of ice age :A spurt in methane emission helped fuel the last major round of global warming. Getty Imagesglobal warming

How seriously should peat bogs be taken in the context of global warming? They sequester vast amounts of carbon by preventing plant material from decaying in the presence of oxygen. A byproduct of this is methane. So while the bogs take care of the carbon, they blast methane into the atmosphere. It is 23 times more potent a greenhouse gas than carbon dioxide. The world’s peatlands contain 180-455 petagrammes (1 petagramme equals 10 15 gramme) of sequestered carbon. They release 20 to 45 teragrammes (1 teragramme is 10-12 grammes) of methane annually, offsetting the carbon capture. “Recent studies indicate the world’s largest peat bog, located in Western Siberia and the size of France and Germany combined, is thawing for the first time in 11,000 years. It could release billions of tonnes of methane gas,” warns David Hyer, geography professor from the Ohio University in USA.

A spurt in methane emission between 11,000 and 12,000 years ago helped fuel the last major round of global warming. This drew the ice age to a close. “Scientists until now dismissed the world’s peatlands as the source of this change because they were thought to have formed too slowly and too late to matter,” said Laurence C Smith, geography professor at the University of California, Los Angeles (UCLA) in USA. A UCLA-Russian Academy of Sciences team reported in Science last year that no peatland dates earlier than about 16,500 years ago, suggesting that no large peatland complex existed before that time. At that time, methane levels hovered around 360 parts per billion by volume and the Earth was in a deep freeze. But as atmospheric methane levels rose, northern bogs appeared in lockstep. Over the next 2,500 years, atmospheric methane levels doubled and temperatures in the ice cores of central Greenland jumped 10°C.
“Temperatures over Greenland jumped another 3.8°C, which thawed more ice and freed more land for bog formation,” said Glen MacDonald, chair of the UCLA Geography Department.

Another study led by Atte Korhola, professor in Arctic Global Change at the University of Helsinki in Finland explained the emergence of the northern peatlands by compiling an extensive radiocarbon-dating database.

Emissions from degraded peatlands will continue until all peat has disappeared. Restoring the peats is the only way to prevent it. Karen Anderson and team from the University of Exeter in the UK devised a mapping tool, by combining laser-scanned and satellite images, to monitor damage inflicted on peatlands by human activities—drainage and deforestation. The Central Kalimantan Peatland Project is aimed at restoring peatlands in Kalimantan in Indonesia.

Tiasa Adhya
Down To Earth Feature Service


Iceberg the size of Luxembourg
An iceberg the size of Luxembourg that contains enough fresh water to supply a third of the world’s population for a year has broken off in the Antarctic continent, with implications for global ocean circulation, scientists said. The iceberg, about 50 miles by 25, broke away from the Mertz glacier around 2,000 miles south of Australia after being rammed by another giant iceberg known as B-9B three weeks ago, satellite images reveal. The two icebergs, over 700m tons, are now drifting close together about 100 miles north of Antarctica. Rob Massom, senior scientist at the Australian Antarctic Division and the Antarctic Climate and Ecosystems Cooperative Research Centre in Hobart, Tasmania, said the location of the icebergs could affect global ocean circulation.

James Sturcke
The Guardian

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