Scientists of the University of Southampton found out that vast chains of volcanoes have been responsible for emitting and removing atmospheric CO2 over extended periods of time, which worked like a feedback mechanism to Earth’s surface temperature, keeping it in a somewhat stable range.
The researchers teamed up with colleagues from the University of Sydney, Australian National University, University of Leeds, and the University of Ottawa and analyzed the cumulative impact of phenomenons in the solid Earth, oceans, and atmosphere over the last 400 million years.
The discoveries of the study were made public in the journal Nature Geoscience.
The process of natural break-down and dissolution of rocks at the planet’s surface is known as chemical weathering.
That process is elementary because its products (chemicals like calcium and magnesium) are flushed in the oceans, where they turn into minerals that trap CO2.
That mechanism is responsible for stabilizing the levels of atmospheric CO2 and, in return, the global climate over geological amounts of time.
Dr. Tom Gernon, the study’s lead author and Associate Professor in Earth Science from the University of Southampton, and member of the Turing Institute, said:
“In this respect, weathering of the Earth’s surface serves as a geological thermostat. But the underlying controls have proven difficult to determine due to the complexity of the Earth system.”
Eelco Rohling, a Professor in Ocean and Climate Change at ANU and the study’s co-author, said that numerous Earth processes are tied to each other, and there are some considerable time lags between processes and their outcomes.
“Understanding the relative influence of specific processes within the Earth system response has therefore been an intractable problem,” Rohling added.
To simplify the analysis, the team created a new “Earth network,” consisting of machine-learning algorithms and simulations of tectonic plates.
That helped them discover the main interaction within the planet’s system and how they changed over time.
The team discovered that continental volcanic arcs were the main factor of weathering intensity over the past 400 million years.
Currently, continental arcs are made out of volcano chains.
Volcanic rocks are chemically reactive and particularly fragmented, making them easy to be weathered and flushed into the oceans to trap certain chemicals.
“It’s a balancing act. On one hand, these volcanoes pumped out large amounts of CO2 that increased atmospheric CO2 levels. On the other hand, these same volcanoes helped remove that carbon via rapid weathering reactions,” explained Martin Palmer, a Professor of Geochemistry from the University of Southampton and co-author of the study.