Weathering of rocks a poor regulator of global temperatures

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A new University of Washington study shows that the textbook understanding of global chemical weathering — in which rocks are dissolved, washed down rivers and eventually end up on the ocean floor to begin the process again — does not depend on Earth’s temperature in the way that geologists had believed.

A new University of Washington study shows that the textbook understanding of global chemical weathering — in which rocks are dissolved, washed down rivers and eventually end up on the ocean floor to begin the process again — does not depend on Earth’s temperature in the way that geologists had believed.

The study, published May 22 in the open-access journal Nature Communications, looks at a key aspect of carbon cycling, the process by which carbon atoms move between the air, rocks and the oceans. The results call into question the role of rocks in setting our planet’s temperature over long timescales.

“Understanding how the Earth transitioned from a hothouse climate in the age of the dinosaurs to today could help us better understand long-term consequences of future climate change,” said corresponding author Joshua Krissansen-Totton, a UW doctoral student in Earth and space sciences.

The current understanding is that Earth’s climate is controlled over periods of millions of years by a natural thermostat related to the weathering of rocks. Carbon dioxide is released into the air by volcanoes, and this gas may then dissolve into rainwater and react with silicon-rich continental rocks, causing chemical weathering of the rocks. This dissolved carbon then flows down rivers into the ocean, where it ultimately gets locked up in carbon-containing limestone on the seafloor.

Read more at University of Washington

Photo credit: Jon Sullivan via Wikimedia Commons