When we hear the word glacier, we most often think of the Arctic, Antarctic and countries in the Northern Hemisphere where glaciers are commonly seen. We are also aware that the climate crisis is responsible for the increased melting of these ice-covers.
But one-sixth of the world’s population residing in places like South America, Africa, and Indonesia, depend on “tropical glaciers,” and they are melting away at a heightened rate. And like the polar ice caps, tropical glaciers – found high in equatorial mountain ranges – are succumbing to global warming.
Peru, known for its wonderfully majestic Andes Mountains, used to be home to 70 percent of the world’s tropical glaciers, including what has been confirmed to be the actual starting point of the Amazon River, high up on the upper flanks of Mismi, an 18,465-foot mountain in the southern Peruvian Andes.
In 2000, reports US News, National Geographic scientists were able to trace the furthest point upstream of the Amazon’s longest continuously flowing tributary, the Apurimac River to a remote spot that was once the tongue of Mismi’s high-altitude glacier. The spot has been marked by plaques from various scientific organizations over the years.
Today, all those plaques are sitting on dry ground, thanks to global warming. “The glacier’s almost gone completely. It will have vanished entirely by around 2021,” says Luzmila Davila, a glaciologist with INAIGEM, Peru’s National Research Institute for Glaciers and Mountain Ecosystems.
“It used to be that you could clearly see where the bottom of the glacier was melting and forming a stream. But now it is just dry rock, sometimes with water trickling down parts of it, but most of the time just dry.”
First detailed investigation of Peruvian glaciers
A research team from Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) – in a comprehensive study published in the journal The Cryosphere on September 30, found that glaciers throughout Peru are strongly affected by changing climatic conditions, leading to considerable ice losses.
While there have been studies done on a few of the glaciers in the Peru-Chili Andes mountains region, there has never been a region-wide uniform measurement undertaken of all the ice masses in the mountain ranges.
To rectify this, the team of researchers led by Dr. Thorsten Seehaus, Institute of Geography at FAU, has worked together with colleagues from Peru to measure the changes in glaciers in the Peruvian Andes between 2000 and 2016 using satellite data.
A total of 170 of previously 1,973 glaciers have disappeared completely, an area roughly equivalent to 80,000 football pitches. Furthermore, they observed a rate of retreat for the period 2013 to 2016 almost four times higher than in the years before.
Besides LandSat imagery, the researchers used data from the joint German-American ‘Shuttle Radar Topography Mission’ from 2000 and the German TanDEM-X satellite which has been active since 2010. Over the entire period, they were able to ascertain the glaciers lost over 8 gigatons of ice. This amounted to a rate of loss in ice mass ice after 2013 that was approximately four times higher than in previous years.
Glaciers as a source of water
Just like Californians depend on yearly snowfall in the Sierra Mountains to supply their water for sustenance, irrigation and to refill groundwater supplies, so do people living in regions dependent on tropical glaciers.
However, “the future contribution of glacier meltwater to the regional runoff puts the continuous water availability for irrigation, mining, hydropower generation, and drinking water supply, especially during the dry season, at risk,” according to the study.
There is also the risk of meltwater lakes forming in areas that could end up breaking lose, creating floods. The water is often held back by the former terminal moraines left by the glacier. If ice or rock avalanches end in the lake or the ice at the core of the moraines melts or erodes, the dam can break or overflow.
The study provides an important foundation for further, improved prognoses of how glaciers can be expected to develop and is a clear sign that glacial melting does not just have an impact on a certain area. Glacial melting does have far-reaching effects, although the Amazon River is not expected to dry up anytime soon. But, experts say that this is a warning of things to come.
