The Earth has gone through many turbulent times: our planet has had periods of global volcanism, epochs of glaciation, sharp increases and decreases in solar radiation fluxes. And yet, for the last 3.8 billion years, life has continued to evolve on our planet.
Scientists suspected that the Earth has some kind of “fuse” that keeps the climate in a habitable range. But until recently, researchers could not prove its existence.
What is this “tool” and how it works, researchers at the Massachusetts Institute of Technology (MIT) found out. They confirmed that the planet has a so-called “stabilizing feedback” mechanism.
This mechanism has been working for hundreds of thousands of years, slowly but surely pushing the Earth’s climate away from the edge of the abyss, in which life can no longer appear again.
Scientists believe this feedback is based on a geological phenomenon called silicate weathering. This is a slow but constant process involving a series of chemical reactions that take place in silicate rocks. They “pull” carbon dioxide out of the atmosphere, “burying” it in sedimentary rocks on the ocean floor.
Scientists have long noted the important role of silicate weathering in regulating the Earth’s carbon cycle.
This mechanism may be the geologically constant force that keeps the concentrations of carbon dioxide in the atmosphere at a level acceptable for the existence of life. As a consequence, global temperatures are “under control” of Mother Earth.
Let us clarify that this idea has been around for many years, but so far there has been no direct evidence that such a feedback operates continuously over millions of years.
Now, MIT researchers have applied mathematical analysis to uncover patterns in paleoclimate data over the past 66 million years.
The research team has been searching the dataset for some recurring phenomena that would keep global temperatures within a habitable range all this long.
So scientists discovered that a constant pattern really exists. The temperature on Earth can fluctuate for some time, critically rising or falling, but then inevitably stabilizes. As if someone is looking after the balance (scientists are not inclined to believe in the supernatural, attributing everything to natural processes).
True, the process of temperature stabilization is very slow: it takes hundreds of thousands of years. This duration coincides with how long, according to researchers, the weathering of silicates lasts.
This is the first work in which evidence supports the existence of such a stabilizing feedback.
The results obtained by MIT scientists may explain how the Earth remained habitable despite the fact that its geological past is filled with dramatic climatic events, many of which could lead to the apocalypse.
“On the one hand, this is good, because now we know that today’s global warming will be neutralized thanks to this stabilizing feedback,” says co-author of the work, graduate student Konstantin Arnscheidt. “But, on the other hand, this will take hundreds of thousands of years, and our decisions today’s problems are needed now.”
The study was published in Science Advances.