IS IT just a coincidence that all the world鈥檚 tallest mountain ranges lie at low latitudes? Apparently not, as it seems warmer climates enhance mountain growth.
Three things control how high a mountain range is likely to grow: the strength of the underlying crust, the magnitude of tectonic forces pushing upwards, and the amount of erosion wearing the mountains down. All of the world鈥檚 highest ranges have strong underlying crust, but until now it wasn鈥檛 clear whether the world鈥檚 tallest peaks were dominated by strong uplift or minimal erosion.
Using satellite images, in Denmark and colleagues mapped all the major mountain ranges between 60掳 north and 60掳 south, plotting their land surface area against elevation. They compared this with the average altitude of the snowline and the latitude of each range. They also modelled the effects of glacial erosion.
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At low latitudes, the warmer climate tended to push the snowline higher, and the mountains grew taller, they found (Nature, ). 鈥淓rosion processes are more effective above the snowline where glacial erosion dominates,鈥� says Vivi Pedersen of Aarhus University. Peaks are rarely more than 1500 metres above the snowline, meaning that low-latitude ranges like the Himalayas (pictured) have a head start over high-latitude ranges because their snowline is much higher.
