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frojack [soylentnews.org] writes:

We add carbon dioxide to the atmosphere through fossil fuel combustion. About 40% of this carbon stays in the atmosphere and roughly 30% enters the ocean, and we are not too sure where all the rest goes.

Most scientists thought the remaining carbon was taken up by plants, but measurements show plants don’t absorb all of the remaining 30% of carbon we generate.

Lots of theories have been expounded about where the leftover carbon is being stored.

A study published in Geophysical Research Letters [wiley.com] suggests some of this carbon may be disappearing underneath the world’s deserts – a process exacerbated by irrigation, beginning as recently as 2000 years ago.

Researchers studying the Tarim Basin [goo.gl] in China, found that around 20 billion metric tons of carbon is stored underneath the desert, dissolved in an aquifer that contains roughly ten times the amount of water held in the Great Lakes.

This is a carbon sink that is not observable in plant or soil, with dissolved inorganic carbon (DIC) leached from irrigated arid land and deposited in the saline/alkaline aquifers under bare deserts. For the most part, this is a one way trip for the carbon. No mechanism has been identified for return to the surface or the atmosphere.

Such carbon sinks formed during groundwater recharge has been reported before. But never on this scale.
The amount of dissolved inorganic carbon stored is 1 to 2 orders of magnitude higher than previously thought.

Original Submission