Food & Climate
The melting glaciers, such as Bolivia’s Huayna Potosi, is a thermometer for accelerating climate change, as its rapid pace warns of the urgency of rising global temperatures. The melting and refreezing of glaciers reveals not only the changes taking place in the climate, but also the fragile dependencies of human civilization on these frozen reservoirs.
This is what Gerd Dercon, Head of the Soil, Water and Crop Nutrition Management Laboratory at the Joint FAO/IAEA Centre for Nuclear Techniques in Food and Agriculture, said.
Year after year, the western Huayna Potosi Glacier is depleting, retreating upslope at an annual rate of about 24 meters. After its retreat, the river leaves behind scattered stones and a meltwater lake, a body of water that did not exist in 1975 and forms the former boundary of the glacier.
So, a team of scientists from the Andes and Himalayas—representing Argentina, Ecuador, Bolivia, Chile, China, and Nepal—is climbing the mountain during the day and installing a machine, a set of boards and wires, to study the Bolivian river as a model of glacier melt.
Their work is technically supported by FAO and the IAEA through the Joint Center, and logistically and financially by the IAEA’s Technical Cooperation Program, according to a report obtained by “Food & Climate” Platform.
Llamas threatened by melting glaciers
In the valleys below the mountain that embraces Bolivia’s western Huayna Potosi glacier, hundreds of thousands of people depend on the glacier’s water. Llamas and alpacas graze the lush pastures, their pastures fed by the seasonal meltwater that has shaped this high-altitude ecosystem for centuries.
Farmers also rely on this water to irrigate their crops and feed their livestock, while a million residents of El Alto, near the Bolivian capital, La Paz, rely on it for drinking water.
For generations, these glacial fields have been an unspoken agreement between the mountain and those who live beneath it, allowing water to flow at a pace that allowed life to flourish. This is now being broken.
The reasons are clear: rising global temperatures are melting glaciers worldwide, but the crisis is accelerating in Bolivia. Strong winds are transporting sediment from ice-free areas that settles into the glacier, darkening its surface and increasing heat absorption.
By analyzing sediments transported from areas now exposed by glacial melt and deposited in lakes and reservoirs, scientists are not only tracking the impact of glacial retreat on sediment distribution but also revealing broader environmental shifts. These climate changes can affect soil fertility, water quality, and chemistry.
Cyclical weather patterns
Cyclical weather patterns, such as El Niño, amplify the warming, causing irregular rainfall fluctuations and rapid snowmelt. If these trends continue, scientists predict that the western Huayna Potosi Glacier—important for drinking water and once thought of as eternal—could disappear completely within 20 years.
“Stopping the glacier’s retreat will not be possible,” says Dercon. “But we have to capture water in several ways.”
In Bolivia, local communities have built more reservoirs, including small ones, dredged some older ones, and raised dam walls.
The land must also be treated differently, shaped to retain water rather than eliminate it, and the soil prepared to receive it. Reforesting the area with native trees and halting overgrazing by hungry llamas and cattle are essential changes to support healthy soils and regenerate the land.
Raising awareness among decision-makers and mobilizing resources to address the coming changes is a crucial first step and an important outcome of scientific expeditions. This is also the case with the establishment of an international monitoring network across the Andes and Himalayas. This network has provided insights into how the parts of the world covered by ice (known as the “cryosphere”) are being affected by climate change and how the retreat of glaciers also affects those living downstream.
What is certain is that these glaciers, once thought to be immovable, are retreating faster than expected.
Now is the time to preserve what remains. Government institutions and farmers in the Bolivian highlands are trying to capture runoff through reservoirs and dams to achieve greater buffering capacity. Furthermore, new arrangements for water use are being developed to ensure that conflicts do not arise in the future.