A study in this week’s Natureshows that mountain height is limited by climate, rather than just by plate tectonics and the strength of the underlying crust. The study shows that when mountains reach heights where it is cold enough for the snow to form permanently, further growth is capped by the moving glaciers.

“Glaciers are very effective at destroying mountains,” said David Engholm, a researcher at Aarhus University in Denmark and lead author of the study. (AFP)

Researchers used radar images of Earth’s surface at different latitudes and found that mountains generally do not rise more than 1,500 metres above the snowline. “So once plate tectonics pushes the surface of the Earth above the snowline altitude, a glacier starts to accumulate, and then basically you reach sort of a steady state where the mountains really do not get any higher,” Egholm told LiveScience.

The idea that moving ice can shaves off layers from a mountain is not new – but this study claims to be the first to demonstrate this is in a single model containing data from all the world’s major mountain ranges. The model shows that “differences in the height of mountain ranges mainly reflect variations in local climate rather than tectonic forces” say the researchers.

This also explains why mountain ranges tend to be higher in the low latitudes closer to the equator, than they are closer to the poles. At lower latitudes, warmer climate means that the snow line is higher, allowing the mountains to grow taller before they start getting eroded. “So we’ve basically explained why there is a link between the presence of glaciers, climate, and the height of mountains,” says Egholm.

High-latitude mountains also tend to have flatter tops than the low altitude ones. “What you see there is that glaciers have basically completely removed the part of the mountains that were above the snowline," Egholm explains.

Posted for Mico Tatalovic

Image: David Lundbek Egholm