<i>Climate cuts mountains down to size </i>
Climate, and not the upward thrust of Earth's clashing tectonic plates, is the main factor limiting the height of mountains across the globe, according to a study published yesterday.
The forbidding peaks of Mount Everest and K2, in other words, might have been even higher were it not for what scientists call the "buzzsaw" effect of glaciers that form when temperatures stay below a certain threshold.
"Glaciers are very effective at destroying mountains," said David Engholm, a researcher at Aarhus University in Denmark and lead author of the study.
"Even if you look at the most active mountain ranges, you see that once plate tectonics have pushed them across the snowline altitude, they do not get much higher," he told AFP by phone.
The study, published in the British journal Nature, showed that peaks are generally prevented from thrusting more than 1,500 meters (5,000 feet) above the line where snow permanently forms.
The findings also explains why none of the world's tallest mountains are found anywhere near the North or South Poles.
"The reason is simply that the snowline is higher at lower latitudes than at higher latitudes," Engholm said.
At the equator, glaciers do not accumulate before an elevation of 5,000 metres (16,400 feet). In Canada and Norway, or Chile and New Zealand, by contrast, the snowline altitude is as low as 1,000 metres (3,300 feet), he said.
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