Science

Cool Karakoram glaciers defy global warming trend

Our Bureau New Delhi | Updated on January 09, 2018 Published on August 15, 2017

Holding firm: The Karakoram mountain range appears to be defying the global trend, with its glaciers stable, if not actively growing

A vortex of air during the summer does the trick, but there are downsides, too

The massive crack in a glacier in Greenland, the unearthing of a mummified couple in Switzerland from a receding glacier, a trillion tonne iceberg breaking off Antarctica — all these events have left scientists and environmentalists alarmed across the globe.

But the Karakoram mountain range appears to be defying the global trend, with its glaciers remaining stable, if not actively growing.

“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 Hayley Fowler, Professor of Climate Change Impacts at Newcastle University. The range spans Pakistan, India and China.

Other side of the coin

A group of scientists from the Newcastle University in the UK, has found that in the summer a vortex of air over Karakoram and western Pamir results in cooling, which is unlike the warming seen in the rest of the Himalayan range.

While the finding appears to be good news, the unnatural cooling also has an impact on the ice melts, which feed rivers, and could have an impact on the flow of streams and rivers dependent on these glaciers. Drastically reduced and exponentially higher ice melts, and consequent flow of the rivers, could have a disastrous impact on India’s food production.

“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,” Fowler said. “We don’t know how climate change will affect this circulation system and what the effect of sudden shifts might be. But the 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,” he warned.

Equilibrium at risk

Glaciers are considered to be stable when the ice melt in summers is equal to the snowfall in winters. Rising temperatures, globally, have been throwing this equilibrium off-balance with more melting and reduced snowfall.

The summer cooling over the range appears to be result of a unique interaction between the Karakoram vortex and the South Asian monsoon, which results in the temperatures over Karakoram and Pamir to cool, even as the Central and Eastern Himalayas are warming, the studies have shown. “Over recent decades, these vortex-monsoon interactions have resulted in stormier conditions over the Karakoram,” it said.

The lead author of the study, Nathan Forsythe, said: “This vortex provides an important temperature control. 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.”

Published on August 15, 2017
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