https://multimedia.scmp.com/news/world/article/3000839/permafrost/index.html
[images and links in online article]
What is permafrost and why might it be the climate change time bomb?
February 19, 2019
Marco Hernandez & Pablo Robles
Forget about carbon emissions and carbon neutrality – if permafrost
continues to melt at current rates, it could be game over for humanity
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 year between 1880 and 2010.
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
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
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
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