Rocks, rain, and carbon dioxide play a crucial role in regulating Earth’s temperature over thousands of years, similar to how a thermostat works. This process is known as weathering, and it has been challenging to understand its temperature sensitivity due to the many factors involved.

However, a new study by scientists at Penn State University has shed some light on this natural phenomenon.

Combining Laboratory Measurements and Soil Analysis

The team combined laboratory measurements and soil analysis from 45 soil sites around the world to create a global estimate of how weathering responds to temperature changes. They discovered that temperature sensitivity measurements in the laboratory were lower than those estimated from soils and rivers.

The scientists used observations from both the lab and field sites to upscale their findings and estimate the global temperature dependence of weathering.

The Balance of Carbon Dioxide in the Atmosphere

Weathering represents part of a delicate balance of carbon dioxide in Earth’s atmosphere. Volcanoes have emitted large amounts of carbon dioxide into the atmosphere over the centuries, but weathering removes it slowly, preventing the planet from becoming a hot house.

Rain takes the carbon dioxide from the atmosphere and creates a weak acid that wears away silicate rocks on the surface. The byproducts are then carried by streams and rivers to the ocean, where the carbon is eventually locked away in sedimentary rocks.

Sensitivity of Weathering to Climate Change

However, much remains unknown about how weathering responds to changing temperatures. It takes thousands or even hundreds of thousands of years for warming to speed up weathering and remove all the carbon dioxide from the atmosphere that humans have added.

The model developed by the Penn State scientists may be helpful in understanding how weathering will respond to future climate change and in evaluating man-made attempts to increase weathering to draw more carbon dioxide from the atmosphere.

„It’s only when you start crossing spatial and time scales that you start seeing what’s really important,” said Susan Brantley, Evan Pugh University Professor and Barnes Professor of Geosciences at Penn State. „Surface area is really important. You can measure all the rate constants you want for that solution in the lab, but until you can tell me how does surface area form out there in the natural system, you are never going to be able to predict the real system.”

In conclusion, this study highlights the crucial role that weathering plays in controlling Earth’s temperature and the delicate balance of carbon dioxide in the atmosphere. It may also provide valuable insights into how we can mitigate the effects of climate change in the future.



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