What is permafrost and why might it be the climate change time bomb?

What is permafrost?

Permafrost is a layer of soil, rock or sediment that is frozen for more than two consecutive years. It is commonly found in snowy, high-altitude mountains. About a quarter of the entire northern hemisphere has permafrost, but it is especially prevalent in areas above the 50th parallel north

Permafrost seals highly compressed carbon and methane gases created from decomposed organic and vegetal remains. Greenhouse gases are released when this frozen layer thaws. In areas not overlain by ice, the surface freezes and thaws annually and is called the “active layer”

THE FEEDBACK EFFECT
The feedback effect occurs when the soil defrosts and releases large amounts of the flammable gas methane, accelerating the warming of the close environment. As the process multiplies, the cycle accelerates exponentially across large reserves of permafrost in the northern hemisphere

According to Nature and the Harvard Review the amount of carbon sequestered in permafrost is four times that of the carbon already released into the atmosphere from modern human activity

WHERE THAT CARBON IS STORED
According to Global Terrestrial Network for Permafrost the map below shows the locations of organic matter carbon

The Tibetan Plateau

If the northern hemisphere is the kingdom of permafrost, then the Tibetan Plateau is the arsenal. Covering some 1,300 million square metres of frozen ground, the Tibetan Plateau is the largest alpine permafrost region in the world

Extreme weather events occurring in other parts of the planet can affect the permafrost on the Tibetan plateau

Global symptoms

Data collection and metrics about changes to the climate have led to much debate about why the weather has become more extreme around the world

Anomalies

Back in 2001 NASA researchers found a statistical correlation between a weak polar vortex and outbreaks of severe cold in the northern hemisphere. However, because the observations are short-term, having been recorded for just 13 years, there is considerable uncertainty over the conclusions

Records clearly indicate a trend of temperatures rising. The graphic below shows deviations from the average monthly temperature in the Northern Hemisphere at the beginning of every decadeyear between 1880 and 2010. We also include the latest data from 2018

The immediate effects of these anomalies are visible in storms, heatwaves and the polar vortex occurring in opposite hemispheres. There are other warning signals such as how fast the ice under the ground is melting

You may remember the story of the Aral Sea shrinking. Some theories pointed to tributary streams being cut off to irrigate crops as the culprit, but regardless, the reality remains – large parts of the sea simply disappeared

The opposite is happening on the Tibetan Plateau. New lakes are appearing, seemingly from out of nowhere. Existing lakes are growing bigger and bigger. Researchers link this to glaciers and permafrost melting

Zhenquancuo lake

Dogai Coring lake

Xianhe lake

The huge impact in the Siling Co lake

Fed by the rivers Boques Tsangpo and Za'gya Zangbo, this salt lake is one that shows one of the biggest increase in water levels in the last 30 years, according to studies conducted by the University of Chinese Academy of Sciences, the lake has grown approximately 45 per cent since 1970

Jiangi Caka lake

Xianhe lake

Rola Co lake

The Rola Co is a large freshwater lake located in the district of Shuanghu, Nagqu province of China. It has grown to the point that it has merged with the neighbouring Danbing lake

It would seem logical to assume that increased rainfall is making the lakes grow, but precipitation and evaporation are in fact declining

The Tibetan Plateau is a vast, treeless region covered in seasonal grass. It is lightly populated because of the cold environment, but the nomads who do live here have watched the grass disappear and the ground melt. The life they knew is vanishing before their eyes.

“The grass used to be up to the knees … Twenty years ago, we had to scythe it down. But now, well, you can see for yourself. It’s so short it looks like moss”

PHUNTSOK DORJE
A Tibetan nomad
in an interview with The Guardian, 2010

“We are working on seven areas, planting trees and trying to restore the ecosystem… This area is particularly fragile. Once the grasslands are destroyed, they rarely come back. It is very difficult to grow grass at high altitude”

A TIBET ENVIRONMENTAL OFFICER
in an interview with The Guardian, 2010

Some organisations, such as the International Permafrost Association, regularly report on the status of these areas and take initiatives to restore some of the green areas in the Tibetan Plateau. However, there are no clear policies from the local governments or the international community as to how these areas can be preserved to prevent permafrost melting