Researchers in the woods investigating rates of weathering in Pennsylvania. Credit: Penn State
Rocks, rain and carbon dioxide help control Earth’s climate over thousands of years—like a thermostat—through a process called weathering. A new study led by Penn State scientists may improve our understanding of how this thermostat responds as temperatures change.
“Life has been on this planet for billions of years, so we know Earth’s temperature has remained consistent enough for there to be liquid water and to support life,” said Susan Brantley, Evan Pugh University Professor and Barnes Professor of Geosciences at Penn State. “The idea is that silicate rock weathering is this thermostat, but no one has ever really agreed on its temperature sensitivity.”
Because many factors go into weathering, it has been challenging to use results of laboratory experiments alone to create global estimates of how weathering responds to temperature changes, the scientists said.
The team combined laboratory measurements and soil analysis from 45 soil sites around the world and many watersheds to better understand weathering of the major rock types on Earth and used those findings to create a global estimate for how weathering responds to temperature.
“When you do experiments in the laboratory versus taking samples from soil or a river, you get different values,” Brantley said. “So what we tried to do in this research is look across those different spatial scales and figure out how we can make sense of all this data geochemists around the world been accumulating about weathering on the planet. And this study is a model for how we can do that.”
Weathering represents part of a balancing act of carbon dioxide in Earth’s atmosphere. Volcanoes have emitted large amounts of carbon dioxide through…
2023-02-05 10:40:02 Study reveals new clues about how ‘Earth’s thermostat’ controls climate
Source from phys.org
An international study, published recently in Nature Geoscience, has revealed new clues about how Earth’s thermometer – the ‘thermostat’ of the planet – has been able to regulate global temperatures for millions of years.
The Earth’s atmosphere and ocean act as a giant ‘thermostat’ that helps to keep our planet’s climate relatively stable, by transferring heat from the equator towards the poles. This process has allowed Earth to withstand sudden, large changes in climate, like sudden droughts, floods, or ice ages, despite large changes in the Sun’s radiation.
This new study, which is the product of several years’ worth of research, offers an answer to a long-standing scientific mystery: how this ‘thermostat’ works.
Using a combination of climate models and observational data, researchers were able to show, conclusively, how the atmospheric and oceanic processes that sustain Earth’s stable climate have worked over millions of years.
The study’s main finding was that the tiny droplets of sea salt that form when the ocean evaporates have played a significant role in the Earth’s thermostat. These salty droplets are known as aerosols, and they act as tiny mirrors, reflecting some of the Sun’s radiation back into space – which helps to keep global temperatures in check.
The study also found that aerosols help to regulate the balance of energy between the equator and the poles. This helps to prevent sudden, large swings in temperature.
This new research provides valuable insight into how the Earth’s climate has been able to remain stable throughout the ages. It also offers a warning to scientists and policy makers: if human activities continue to disrupt natural processes, like the formation of aerosols, it could severely upset the delicate balance that regulates our climate.
