Permafrost: a climate time bomb?

Diseases long locked into the ice

YAKUTSK, Russia, Dec 5, (AFP): The Earth’s vast tracts of permafrost hold billions of tonnes of planet-heating greenhouse gases that scientists warn will be released by global warming, along with diseases long locked into the ice. Here is some background. A quarter of the north – Permafrost – soil that is frozen, although not necessarily permanently as it name implies – is found mostly in the Northern Hemisphere, where it covers about a quarter of exposed land and is generally thousands of years old.

It covers a wide belt between the Arctic Circle and boreal forests, spanning Alaska, Canada, northern Europe and Russia.

Permafrost exists to a lesser degree in the Southern Hemisphere where there is less ground to freeze, including in the South American Andes and below Antarctica.

It can vary in depth from a few metres to more than 100.

Tonnes of locked-in carbon – Locked into the permafrost is an estimated 1.7 trillion tonnes of carbon in the form of frozen organic matter – the remains of rotted plants and long-dead animals trapped in sediment and later covered by ice sheets.

When permafrost thaws, this matter warms up and decomposes, eventually releasing the carbon that it holds as carbon dioxide (CO2) and methane, gases which have a greenhouse warming effect on the planet.

Permafrost soils contain roughly twice as much carbon – mainly in the form of methane and CO2 – as Earth’s atmosphere.

Most of the carbon stocks are thought to reside fairly close to the surface.

Vicious circle of warming – The release of greenhouse gases threatens a vicious circle in the warming of the Earth, jeopardizing the objective set in the 2015 Paris Agreement to strive to limit the rise in temperature to 1.5ºC (2.7ºF) above pre-industrial levels.

CO2 is the most abundant greenhouse gas blamed for global warming but methane is 25 times more efficient at trapping heat.

Adding these into the atmosphere will spur further warming and ice melt, which will in turn cause more thawing of the permafrost and free up more locked-up carbon.

Even if global warming were stabilized at around 2ºC, research points to a 30-percent loss of permafrost by 2100, researcher Susan Natali of the Woods Hole Research Center told 2015 climate talks in Bonn.

This could reach up to 70 percent assuming emissions continue on their current trajectory, her research said, warning that “emissions from permafrost could lead to out-of-control global warming”.

Frozen diseases? – The thawing of the permafrost also threatens to unlock disease-causing bacteria and viruses long trapped in the ice.