Haa Valley

Photo by Douglas J. McLaughlin/Creative Commons

The small mountain country of Bhutan is home to 700,000 people, many of whom rely on hydroelectric power that could be interrupted by the loss of the glaciers.


Bhutan's melting glaciers hold a mirror to Earth's future climate

by Matt Rhodes
Oct 15, 2012

Bhutan Map

geology.com

Putnam

Matt Rhodes/MEDILL

Aaron Putnam (left) and colleague George Denton, professor of geological sciences at the University of the Maine (right) at the Comer Conference.

Scott Travis2

Matt Rhodes/MEDILL

Scott Travis is the facility manager of the Comer family estate and is assisting climate scientists in their research in Bhutan.

Hiking up to 16,000 feet in the Himalayas, climate scientists plan to pin down how fast glaciers are melting near the top of the world.

Bhutan, located at the center of the highlands of the Himalayas, is hosting a team of geoscientists as they research the small mountain country's glaciers and forests. The area offers a snapshot of how changing temperatures are affecting glacial regions and global climate.

The one-month expedition is a joint, three-pronged operation combining proxies from glaciology, glacier geology and dendrochronology dating climate changes by studying growth rings in tree trunks).

Part of the job of glimpsing climate impacts requires removing cores - or "cookies" from trees to read the tree rings. That job that calls for Edward R. Cook, dendrochronologist at the Columbia University’s Tree Ring Research Laboratory the Lamont-Doherty Earth Observatory. Cook will take the cores as a member of the research team trekking up to their field area located at 16,000 feet. 

“We’ll be going through some of the deepest, oldest forests that you can find in the Himalayas,” says Aaron Putnam, postdoctoral research scientist at Lamont-Doherty. “The Bhutanese have been very conscious about not eliminating their forests.”

Working at such a high altitude doesn't come without risks. "Not everyone's worked up that high and sometimes it doesn't even matter," says Putnam. "If the altitude hits you, it hits you."

Other challenges include getting a 2,000-watt, 50-pound portable generator from Wisconsin to the Himalayas. The generator never got beyond Minneapolis but one of the team's hosts in Bhutan located a replacement, Putnam reports.

The team hopes to get a record of several centuries from the sampled cores of the trees. “Maybe even 1,000 years of tree ring variability, which they think reflects changes in atmospheric temperature,” reported Putnam at the annual Comer Conference on abrupt climate change held this fall in Wisconsin.

The annual climate conference brings reports of climate change from around the globe as leading scientists gather to share data.

Once the team reaches their field area, they will begin drilling ablation stakes directly into a select series of glaciers. Summer Rouper, a glaciologist from Brigham Young University, leads this side of the triad.

Drilling the stakes into the glaciers initiates a long-term monitoring program enabling the team to get melt rates of the glaciers. Members of the team will periodically check on the stakes and tick off how much of the glacier has melted, since the last checkpoint. Think of how a child stands next to a doorframe and marks their height as they grow up. It’s the same principle at work with the ablation stakes, but in the case of the glaciers, they are experiencing a shrink spurt rather than a growth spurt.

The stakes work in tandem with the automatic weather stations the team is building in their field area, which will monitor what the weather over the glaciers is doing. This allows the scientists to monitor how the climate is changing in real time.

“It’s a means of calibration,” says Putnam. “We know the glaciers respond to temperature there, but we don’t know exactly how sensitive they are and that sensitivity is key.”

In addition to studying the state of glaciers at present, the team is also collecting data to reconstruct glaciers of the past. Led by principal investigator, Joerg Schaefer, professor at Columbia's Department of Earth and Environmental Sciences, the group is mapping the ridges and moraines demarcated by past glaciers.

“If we can reconstruct the geometry of glaciers by using these mapped moraines we can actually quantify how much the climate has changed,” says Putnam. “Then the big question is when was it that much colder to produce a moraine outside, so then we use beryllium-10 to get the age of the moraine. And then we have the x-axis, which is time and the y-axis, which is temperature, and we can actually plot the temperature evolution over time.”

The beryllium-10 isotope only appears in rocks when they are exposed to the air - in other words, when glaciers have retreated. The levels of the isotope offer a paleo calendar of when glaciers advanced and retreated.

The team will then match this temperature evolution with other records of paleoclimate around the planet, revealing a better understanding of the mechanisms that drive climate change.

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The team’s research will not only add clarity to the dynamics of climate change at large, but will also directly benefit Bhutan and its neighboring countries.

“We’ll be helping Bhutan’s Ministry of Agriculture better understand the formation of glacial lakes – run-off water from the glaciers that causes problems flooding these steep Himalayan valleys,” says Facility Manager of the Comer Estate, Steve Travis, who will also be assisting Putnam and the rest of the team in Bhutan.

Travis describes his role as a “go-for” (pronounced gopher). Whatever the team needs, Travis will go-for it and get it, he says.

Travis worked with Putnam before in New Zealand and Patagonia.

“After five seasons in the field doing exposure dating, I can be real specific and helpful,” says Travis.

As the climate warms, many of the larger glaciers that historically produced giant meltwater streams withdraw from the moraines and form proglacial lakes instead, explains Putnam. These lakes lead to flooding because not enough water is making it out of the moraine downstream.

The glacier lake outburst of Lugge Tsho in northern Bhutan killed 21 people in 1994.

The decreasing water flow is also adversely affecting the biggest driver of Bhutan’s economy – the hydropower sector.

Bhutan exports much of its energy to India through a system of hydroelectricity power plants that entirely depend on the downstream water discharge from melting glaciers and snow packs. Thus far, Bhutan has managed to sustain their hydropower industry while remaining a net carbon sink - a place that absorbs more carbon that it emits. The secret is in Bhutan's preservation of forests that blanket some 70 percent of the country and absorb enough carbon to more than offset emissions from the nation's agriculture and industry, with room to grow.

Bhutan’s potential output of hydropower had previously been estimated at 30,000 megawatts (mW). But currently, the country has an output of about 1,500 mW from four plants and needs more plants to generate more power.

India has agreed to assist Bhutan in developing the hydropower sector by funding construction of six more plants and plans to purchase at least 10,000 mW of power from the partnership by 2020.

But a variant climate may change such ambitions.

“No more glaciers, no more power,” says Travis.

“You’ll find the same thing in New Zealand. They built a series of canals that trap the water and have hydropower associated with all the glacial run-off around Lake Pukaki,” he adds. For India, which faced massive power outages this summer. The climate stakes are very high.

The team hopes their research will aid Bhutan in its plans for future development in its hydropower sector, while continuing to absorb more carbon than it’s emitting.

“They’re smart and want to do it right from the beginning,” says Travis. “I wish them all the best with what they’re trying to do and if we can go help them understand climate change that’s even better.”