Scientists from Cambridge University and NTU Singapore have discovered that slow-motion collisions of tectonic plates drag more carbon into Earth’s interior than previously thought.
They found that the carbon drawn into Earth’s interior at subduction zones. Tends to stay locked away at depth, rather than resurfacing in the form of volcanic eruptions. Their findings suggest that only one third of carbon recycled beneath volcanic chains returns to the surface via recycling, in contrast to previous theories that what goes down mostly comes back up.
One of the ways to combat climate change is to find ways to reduce the amount of CO2 in Earth’s atmosphere. By studying how carbon behaves in the deep Earth, which stores the majority of our planet’s carbon, scientists can better understand the entire lifecycle of carbon on Earth, and how it flows between the atmosphere, oceans and life at the surface.
The best-understood parts of the carbon cycle are at or near the Earth’s surface, but deep carbon stores play a key role in maintaining the habitability of our planet by regulating atmospheric CO2 levels.
There are a number of ways for carbon to be released back into the atmosphere (as CO2) but there is only one path in which it can return to the Earth’s interior; by plate subduction. Here, surface carbon, for example in the form of seashells and micro-organisms which have locked atmospheric CO2 into their shells, is channeled into the Earth’s interior. Scientists had previously thought that much of this carbon was then returned to the atmosphere as CO2 via emissions from volcanoes. However, the new study reveals that chemical reactions taking place in rocks swallowed up at subduction zones trap carbon and send it deeper into Earth’s interior-stopping some of it coming back to Earth’s surface.
https://phys.org/news/2021-07-earth-interior-swallowing-carbon-thought.html