Deserts are a giant carbon sink sucking up 30pc of world’s CO2

29 Jul 2015

Water found in the Tarim Basin is absorbing huge amounts of CO2. Image via Yan Li

New research has solved a running mystery among climate scientists looking for the ‘missing carbon sink’, with new evidence showing that our planet’s deserts are sucking up 30pc of the world’s total carbon emissions.

Until now, researchers have been left somewhat puzzled as to where exactly the CO2 we are pumping into the atmosphere is going and where the source of the great carbon sink was.

What was clear was that 40pc of these emissions are rising into the Earth’s atmosphere where it creates climate-changing effects, while a further 30pc was known to be absorbed by our planet’s oceans, which themselves account for 70pc of Earth’s total surface area.

According to the American Geophysical Union, the remaining 30pc was only believed to be partially absorbed by vegetation, but now new research shows that the great carbon sink is actually underground in deserts.

The new research conducted by a team from the Chinese Academy of Sciences analysed massive aquifers beneath the scorching Chinese deserts and found that, as a result of farming, carbon emissions are being absorbed by the crops above and fed into water underground.

1trn tonnes of CO2 stored underground in desert aquifers

The study led by desert biogeochemist Yan Li suggests that as much as 14 times more carbon than had previously been estimated is being stored underground in these vast aquifers across the planet, covering an area equivalent in size to North America.

In the Taklamakan Desert in the Tarim Basin in China alone – where the study was undertaken – there is believed to be somewhere in the region of 20bn metric tonnes of CO2 stored, while the world’s desert aquifers could account for as much as 1trn metric tonnes of CO2 in total.

The process of this carbon being moved underground through desert crops is believed to be exacerbated by over-irrigation by farmers in desert lands, which washes salt and CO2 down into the aquifers.

While the burial of carbon can be found outside of man-made influences, the study finds it to be 12-times higher as a result of over-irrigation.

Li and the team suggest their findings offer significantly more accurate climate models for the future and calculations for Earth’s ‘climate budget’.

Colm Gorey was a senior journalist with Silicon Republic