Scientists from NTU Singapore and from Cambridge University recently discovered that the tectonic plate collisions pull more CO2 back into the Earth’s interior than had been thought until now.
As a result of their findings it was established that the carbon dioxide dragged into the Earth’s interior is locked away, whereas previously it was assumed that most of the carbon was released back into the atmosphere in the form of volcanic emissions.
Contrary to this now outdated belief, the scientists found that the Earth withholds as much as two thirds of the CO2 that it pulls back into its depths.
Studying the ways in which carbon dioxide behaves beneath the Earth’s surface can help scientists better understand the lifecycle of carbon on the planet, which, in turn, is greatly beneficial to tackling the issue of climate change.
Currently, the parts of the carbon lifecycle that are best understood are those that take place near the Earth’s surface. However, the deep CO2 storage plays an essential role in regulating the carbon levels in the atmosphere, and therefore the planet’s habitability.
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According to these recent studies, much of the carbon that was previously thought to resurface again via volcanic emissions partakes in chemical reactions in rocks that are engulfed at subduction zones. And as a result of these reactions, the carbon is swallowed even deeper below the Earth’s surface and is effectively prevented from re-emerging again.
The studies also revealed that the chemical transformation causes carbonate rocks that share the chemical makeup of chalk to become richer in magnesium and loose calcium as they are sucked deeper into the Earth’s core. What this means is that the carbonate becomes less soluble and cannot be dissolved into the volcanic fluids.
And instead, most of it travels deeper still into the mantle where under the effects of the pressure and temperatures it turns into diamond.
More research in this field is expected to be done, and scientists are confident it will tremendously help find better ways to capture and lock CO2 and possibly solve the climate crisis.
Reference: “Deep carbon cycle constrained by carbonate solubility” by Stefan Farsang, Marion Louvel, Chaoshuai Zhao, Mohamed Mezouar, Angelika D. Rosa, Remo N. Widmer, Xiaolei Feng, Jin Liu and Simon A. T. Redfern, 14 July 2021, Nature Communications.