A statistical analysis of the Earth’s climate indicates that a stabilizing mechanism dampens strong climate fluctuations. This could have contributed to the fact that the earth has never gotten too hot or too cold for life for billions of years.
As Constantin W. Arnscheidt and Daniel H. Rothmann from the Massachusetts Institute of Technology report, the temperature fluctuations over periods of up to 400,000 years are no higher than on time scales of around 4000 years.
For statistical fluctuations, however, one would expect that the longer the period of time, the further apart the maximum and minimum temperatures would be. The finding therefore indicates that a mechanism stabilizes the Earth’s climate over these short periods of time, the team writes in the journal Science Advances.
One of the biggest mysteries about Earth’s climate is why it is so stable. The fluctuations between snowball earth and the greenhouse world of the dinosaur age may seem extreme, but our neighboring planets Venus and Mars already show how hostile to life an earth-like planet can become.
Many experts therefore suspect that geological feedback loops kept the Earth’s climate habitable. One of them is silicate weathering.
The mineral silicate is contained in almost all rocks and slowly dissolves under the influence of carbonic acid – which is produced by dissolving carbon dioxide in water. In doing so, it permanently removes the carbon dioxide from the atmosphere.
This process runs faster the warmer it is and the more carbon dioxide there is in the air. As a result, high carbon dioxide concentrations mean that the gas is bound faster and faster, while at low concentrations it remains in the atmosphere for a long time and accumulates.
According to Arnscheidt and Rothmann, this process is the most likely candidate for the stabilization they found because it should theoretically take place on the time scales of a few thousand to a few hundred thousand years found in the analysis.
However, the two researchers point out that their finding only partially explains why the earth has always remained habitable.
Above about 400,000 years, the fluctuations increase again over time, as theoretically expected – over very long periods of time there seems to be no mitigating influence on the earth’s climate. So it may just be coincidence that none of these climate freaks were big enough to wipe out life on Earth.
The original of this article “The earth’s climate stabilizes itself” comes from Spektrum.de.
