Himalayan Glaciers Will Continue to Shrink

Glaciers in the Himalayas will continue to shrink for many years even if the climate remains steady, said Brigham Young University geology professor Summer Rupper. She carried her research on glaciers of Bhutan, a region of monsoonal Himalayas. 

Her study conservatively estimates that almost 10 percent of Bhutan's glaciers would vanish within the next few decades and there will be a 30 percent drop in the melt water that comes from these glaciers.

Professor Rupper said that  increasing temperatures were a key factor behind the retreat of these glaciers. A number of climate factors such as wind, humidity, precipitation and evaporation can affect how glaciers behave. An imbalance in these factors could take decades for the glaciers to completely respond.

"These particular glaciers have seen so much warming in the past few decades that they're currently playing lots of catch up," Rupper explains.

In order to avoid such glacier retreat, the snowfall rates in Bhutan need to double. But due to warmer temperature this is impossible as this leads to rainfall instead of snow.

If glaciers continue to lose more water than they gain, the combination of more rain and more glacial melt will increase the probability of flooding.

"Much of the world's population is just downstream of the Himalayas," Rupper points out. "A lot of culture and history could be lost, not just for Bhutan but for neighboring nations facing the same risks."

Rupper demonstrated that if temperatures were to rise just 1 degree Celsius, the Bhutanese glaciers would shrink by 25 percent and the annual melt water would drop by as much as 65 percent. 

To make more precise predictions for Bhutan, Rupper and BYU graduate students Landon Burgener and Josh Maurer joined researchers from Columbia University, the Lamont-Doherty Earth Observatory, NASA and Bhutan's Department of Hydro-Meteorological Services

A weather station and glacier monitoring equipment were set up on the ice blocks to gather real-time data in the months and years to follow.

"It took seven days just to get to the target glacier," Rupper recounts, having returned in October. "For our pack animals, horsemen and guides, that terrain and elevation are a way of life, but I'll admit the westerners in the group were a bit slower-moving."

The government hopes to use Rupper's research to make long-term decisions about the nation's water resources and flooding hazards.

"They could potentially have a better idea of where best to fortify homes or build new power plants," Rupper says. "Hopefully, good science can lead to good engineering solutions for the changes we're likely to witness in the coming decades."

The study was published in the Geophysical Research Letters.