'Karakoram anomaly' defies climate change

A 'vortex' of cold air breeze over the Karakoram mountain range has been causing glaciers to continue growing in spite of climate change, scientists have shown. 

This peculiar phenomenon, which has been dubbed the 'Karakoram anomaly', was studied recently by scientists at Newcastle University in the UK and is thought to explain how glaciers in some parts of the Himalayas have been acting differently to those across most other parts of the world.
During the winter, the vortex is thought to affect temperatures across the entire 2,000 kilometres mountain  range, but in the summer it contracts and its influence continues to affect only the Karakoram and western Pamir region.

Pamir mountains

This induces an anomalous cooling in summer which is different to the warming seen over the rest of the Himalaya.

Co-author Professor Hayley Fowler, says this Karakoram vortex goes some way to explaining why the glaciers in this region are behaving differently to those in most other parts of the world.

Karakoram Mountains

"While most glaciers are retreating as a result of global warming, the glaciers of the Karakoram range in South Asia are stable or even growing," said study co-author Professor Hayley Fowler.

"Most climate models suggest warming over the whole region in summer as well as in winter."

"However, our study has shown that large-scale circulation is controlling regional variability in atmospheric temperatures, with recent cooling of summer temperatures."

"[This] circulation system is currently providing a dampening effect on global warming, reducing glacial melt in the Karakoram region and any change will have a significant effect on ice melt rates, which would ultimately affect river flows in the region." 

Acting like a counter-weighted temperature control, the unique summer interaction of the Karakoram vortex and the South Asian Monsoon causes temperatures in the Karakoram and Pamir to cool while those in the Central and Eastern Himalaya are warming, and vice versa.

Lenin peak in Pamir mountains

Over recent decades, these vortex-monsoon interactions have resulted in stormier conditions over the Karakoram.

"This vortex provides an important temperature control," explains Newcastle University's Dr Nathan Forsythe, lead author of the study.

"It is therefore important to look at how it has changed and influenced temperature over the last century so we can better understand how a change in the system might affect future climate.

"This is of huge importance in terms of food security because of the large populations that rely on water resources from snow and ice melt from the mountainous catchments to grow their irrigated crops in the Indus Plains of the Sindh and Punjab states and provinces of Pakistan and India."

Source: phys.org