New Satellite Imagery Shows Rapid Pace of Andean Glacier Melt

Climate change has long been known to be a stressor on glaciers the world over, but a recent study published in Nature Geoscience, reveals just how bad it’s been for those in the Andes: Glaciers in this South American mountain range have the unfortunate distinction of being both the fastest melting and the largest contributors to sea level rise in the world.

Glacial melt has been watched carefully for decades, but because of limitations in technology and methodologies, scientists haven’t gotten the most precise picture of how much melting is occurring, or how fast.

Previous techniques looked at regional locations scattered throughout the Andes like the Northern Patagonian Icefield and then extrapolated those findings. Others gave hazy estimates from low-resolution, remote-sensing images. But these methods can miss individual glaciers and clusters of just a few or more.

In an attempt to refine understanding of Andes-wide glacial melt, the researchers harnessed the image-collecting power of a satellite with the Asimovian name of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). ASTER has been taking high-resolution, stereoscopic images of the Andes since 2000. By compiling these images and integrating them into digital models, the study’s scientists were not only able to get a new ice loss estimate for the entire Andes, but also for individual regions and individual glaciers over the past two decades. 

With this high resolution dataset, the researchers determined that the entire glacial range in the Andes shrunk about 23 gigatons (1 gigaton=1 billion tons) since 2000—more than previous studies have found—and account for 10 percent of global sea level rise. At this rate, some of these ancient glaciers will be gone in just over two centuries—but the rate is accelerating.

Digging through the data, the researchers also parsed out an array of differing melt rates between glaciers that revealed the areas of the heaviest melting: Patagonia (Chile, Argentina) and the tropical Andes (Colombia, Ecuador, Peru, and Bolivia). Previous research has shown that low altitude glaciers in some of these areas like Peru have lost as much as 50 percent of their mass since 1970.   

“[Patagonia] is the region that contains the largest surface of ice, and [so] it’s normal to expect that the highest loss is going to be there,” lead author and glaciologist Inés Dussaillant told GlacierHub over the phone, adding that glaciers terminating in oceans and large lakes like those in Patagonia also experience heavy amounts of calving—which accounts for more than half of all the ice mass loss observed in the Andes. The glaciers in the tropics—mostly in Ecuador and Colombia—Dussaillant explained, are relatively small and highly sensitive to changes in climate. “A small change in temperature can make tropical glaciers lose a lot of mass,” she said. 

Glaciar el Juncal, Región de Valparaíso, Chile (Credit: Eyal Levy)

Perhaps the most troubling of the team’s findings, however, dealt with glaciers’ contribution of freshwater to rivers through snow and ice melt. During the summer months, snow and ice melt from glaciers flows into streams and rivers, adding to the overall water availability of a particular region. This is particularly important in the Dry Andes of the northern and central regions of Chile and Argentina. Since 2010, these heavily populated semi-arid regions have been strapped in what climatologists have called a megadrought. The team found that increased glacial melting in these areas since 2009 actually helped to mitigate some of the most severe impacts of the drought. But as glaciers continue to shrink because of anthropogenic climate change, their ability to act as this natural salve is going to diminish or disappear.

“They are not going to be able to contribute to rivers eternally,” remarked Dussaillant. “There will be a moment where they’ll no longer be able to contribute during these periods of drought.” 

Campos de Hielo Sur, Parque Torres del Paine Región de Magallanes, Chile
(Credit: Eyal Levy)

This point highlights the larger implications of the study, which is that millions of people live near, and depend upon, these glaciers in the Andes, and the drastic reduction or total disappearance of them is going to have potentially severe consequences. Dussaillant, who is Chilean, pointed out that more than half of the population of Chile lives in or near the capital city Santiago, which lies in this region.

Eyal Levy, an industrial engineer and Andean climber who is also from Chile, told GlacierHub that Chileans are “starting to become very worried about the water stress. He added that rural areas and poorer communes around Santiago have been “seriously impacted.” 

Glaciers are a conspicuous part of the everyday scenery, Levy said, and their shrinking takes a toll on people’s emotions. “People talk about melting glaciers with sadness, worry, and without knowing what to do,” he said.

Dussaillant hopes that the high resolution dataset gathered from this study will be used by other glaciologists for local or regional studies. “I study glaciers because they tell us what is happening,” she said. “It’s showing us that climate is changing, and the climate is a global thing. So what’s happening in the Andes … it concerns us all.” 

Read More on GlacierHub:

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Making Connections at the 2019 International Mountain Conference

Copper Versus Ice: Chilean Mine Would Excavate Five Glaciers

Glaciers neighboring Chile's Andina mine. (©Cristobal Hurtado, please contact the photographer before using)
Glaciers neighboring Chile’s Andina mine. (©Cristobal Hurtado, please contact the photographer before using)

The glaciers of Chile are threatened not just by global warming, but by mining operations high in the snow-peaked Andes cordillera.

On July 24, Chile’s state-owned copper mining company Codelco, the world’s largest producer of the metal, proposed changes to a controversial $6.8 billion expansion of its Andina mine. Whether the new proposal gets the green light from environmental authorities could determine the fate of 26 glaciers in the central Andes, which form a watershed that supplies drinking water to the 6 million Chileans living in the country’s capital, Santiago.

Activists were not impressed. “Nothing has changed. Andina 244 will continue destroying glaciers,” Greenpeace Chile wrote in a response. In March, Chilean Greenpeace activists declared a “Glacier Republic,” a sovereign state covering 23,000 square kilometers of glaciers in Chile that already has over 15,000 “citizens,” to push adoption of a law to protect Chile’s glaciers. And on Sep. 27, two thousand people, many of them children wearing superhero costumes, marched to the presidential palace La Moneda, in Santiago, to urge president Bachelet to write glacier protection laws.

The site of Andina 244, Codelco's proposed expansion of its Andina copper mine. (©Codelco)
The site of Andina 244, Codelco’s proposed expansion of its Andina copper mine. (©Codelco)

The revisions to Codelco’s project, dubbed Andina 244, came in response to concerns voiced by environmentalists and local authorities in more than 2,000 public comments on the project. But those revisions would do little to alter the mine’s direct impacts on the glaciers.

Codelco had planned to remove six so-called rock glaciers to get at copper ore under the earth; opponents also charged that dust from the project would damage 20 visible ice glaciers that extend along the cordillera. Under the revised project, the range of the open-pit mine was shifted so that it will require partial removal of five rock glaciers instead of six, but the difference in total area is negligible: 89.94 acres instead of 89.97 acres. Codelco also announced that its own research, completed at the request of government authorities, showed that dust from the expansion would not accelerate melting at the neighboring visible ice, or white, glaciers. (Typically, little or no ice is visible at the surface of rock glaciers.)

At least one scientist found flaws in the company’s modeling: Alexander Brenning, a glaciologist from the University of Waterloo in Ontario, who has spent many years studying Chile’s glaciers, said Codelco’s wind field data does not match data from meteorological stations in the area, which could skew its calculations of particle dispersion rates. Dust and particulate matter are known to accelerate melting of glaciers given that they darken the glaciers’ surfaces, causing them to absorb more heat from the sun. “You find subtle contradictions. According to their models, dust from their mine won’t affect white glaciers, but anecdotally they mention that you can sometimes see dust clouds from neighboring mine Los Bronces,” he said.

In the revised project, Codelco also proposed measures to protect water resources: it would recycle 65% of the water used at the mine and inject fresh water directly into a nearby river to compensate for loss of glacial meltwater. And the company promised to study and preserve glaciers that feed the area’s major rivers—Mapocho, Maipo and Blanco—over the life of the project, through 2058.

Rio Mapocho at Yerba Loca (“Crazy Herb”), a protected nature sanctuary. (©John Bankson)
Rio Mapocho at Yerba Loca (“Crazy Herb”), a protected nature sanctuary. (©John Bankson)


For the Chilean government, weighing water and ice against copper makes for a complicated calculus. Codelco is 100% owned by the state and provides 14% of the government’s revenues, making it a major lifeblood for the country, one of South America’s strongest economies. According to Codelco, Andina 244 would also generate 18,000 jobs over the next six years. The expansion of the mine is part of a larger revamp at Codelco that is apparently needed if the company is to maintain its position as the world’s number one copper producer. Profits were down by almost a third in the first half of this year due to a slide in global copper prices, according to Reuters. (Profit margins, though, are a very generous 40%.)

Some 31,000 glaciers span the Chilean side of the Andes cordillera, which represent 82% percent of all glaciers in South America. Among these are thousands of rock glaciers, which are quite different from the glittering blue ice sheets and jagged crowns and slopes of translucent white that most people associate with the term. Rock glaciers are glacier-like formations consisting of angular rock blocks, between which glacier ice is packed, but not visible. They are just as important to water reserves as white glaciers .

Santiago with the Andes mountains towering behind it, Spring 2013. (©Armando Lobos)
Santiago with the Andes mountains towering behind it, Spring 2013. (©Armando Lobos)

Despite a lack of good laws governing the country’s glaciers, Chilean authorities do have some bite when it comes to protecting them. In July of 2013, a Chilean court suspended the operations of Pascua Lama, a mine run by Canada’s Barrick Gold, after indigenous communities were able to prove that the company had damaged glaciers near the mine, violating its environmental permit.

“Environmental awareness in Chile has been increasing over the last 20 or 30 years,” said Brenning. “NGOs are getting stronger, and the environmental thoroughness with which different government bodies involved examine those projects has been increasing over the last decade, in particular the glaciology group of the Chilean water authority.”

A march in defense of water, partially in protest of Andina 244, on April 26, 2013 in Santiago's Parque Almagro. (©Rafael Edwards)
A march in defense of water, partially in protest of Andina 244, on April 26, 2013 in Santiago’s Parque Almagro. (©Rafael Edwards)