Scientists at Harvard University managed to expose a link between plate tectonics and the shifting atmospheric conditions that govern a certain region at a given time. They turned to the Andes Mountains, which, according to the study, were formed because the area turned from a lush forest into the desert we can see today.
While this may seem sort of, well, impossible, their arguments have a very solid scientific foundation. Professor Brendan Meade argues that a change in the amounts of rain falling over the western borders of the Americas determined the metamorphosis of the entire area, turning a significant portion of the continent into an arid wasteland. However, the effect this change had on the way tectonic plates move eluded the scientists for a long time.
Now, they were finally able to determine that reduced rain meant reduced erosion of the forming mountains. While this may not seem like much, in truth, the speed at which the Nazca and the South American tectonic plates were converging decreased significantly, from 15 centimeters (6 inches) a year to 7 centimeters (2.7 inches). This meant that the mountains, free from the effects of the water, were finally free to "lift off", reaching the altitudes they still are at today.
"It's this amazing story – we're at the beginning of understanding how climate affects plate tectonics," said Meade, one of the authors of the new study. Rain affects mountain growth, whereas mountain growth affects the tectonic plate underneath it. The Nazca plate was made several times heavier with the weight of the whole Andes range, which, including friction, caused this drastic reduction in convergence speed.
The researchers answered people fearing that global warming may have similar effects on today's geographic set-up by saying that the conditions for such large-scale events to occur must be kept in place not for tens of years, but for hundreds of millennia, if anything is to happen.
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