Glacial melt creates Andes time bomb

Melting Andean lakes can cause havoc downstream. Image: By Willian Justen de Vasconcellos on Unsplash

The speed of glacial melt in parts of Latin America is threatening water supplies – and life and limb in cities downstream.

LONDON, 16 December, 2019 – Rising regional temperatures in the Andes and the warming of waters in the Pacific Ocean, off Latin America’s west coast, are driving the mountains’ glacial melt to alarming new speeds.

Long-term water supplies to many millions of people are under threat. Capital cities like Lima in Peru and La Paz in Bolivia, largely dependent on water from glacier melt flows, face an uncertain future.

The prospects for agriculture – a mainstay of the economies of countries in the region – will be imperilled as land dries up.

There is another, potentially lethal consequence of the melting of the Andes’ glaciers. In 1941, large chunks of ice breaking off a glacier and falling into Lake Palcacocha, more than 4,500 metres up in the Cordillera Blanca mountain range in the Peruvian Andes, are said to have triggered what’s known as a glacial lake outburst flood (GLOF).

“As temperatures in the region continue to rise, the danger level increases”

The sudden influx of ice caused the lake to burst, its waters racing down a canyon to burst another glacial lake below and then on to flood the city of Huarez, more than 20 kilometres away. It’s estimated that more than 4,000 people – about a third of the city’s population at the time – were killed.

Rising temperatures caused by climate change in mountain ranges around the world are leading to an ever-increasing number of GLOF incidents. Mountainous countries like Peru and Nepal, in the Himalayas, are particularly vulnerable to the sudden flooding caused when glacial lakes burst.

In the aftermath of the 1941 flood, a dam was built on Lake Palcacocha: at first the lake slowly refilled, but in recent years the process accelerated due to increased temperatures and more glacial melt.

Flexible pipes have been used to siphon waters off from the lake but experts say it’s only a matter of time before Lake Palcacocha again bursts its banks. The dam, they say, will be swept away. The consequences would be devastating as a wave up to 30 metres tall is unleashed.

Increased population

The city of Huarez has become a big tourist destination and its population has grown to more than 120,000. Large numbers of farmers have moved onto lands below Lake Palcacocha. Mine workers are also active in the area, searching for valuable minerals in ground uncovered by the melting of the glaciers.

Various safety measures are being installed. After years of wrangling and bureaucratic delays, a flood early warning system is about to be activated in the area.

Installation of the system has also been subject to sabotage by local farmers who say that the introduction of the technology has somehow interfered with natural weather patterns.

Monitoring systems have improved – with often daily glacial avalanches being recorded. Inaigem, the national research institute on glaciers and mountain ecosystems, provides a live video of Lake Palcacocha water flows. But as temperatures in the region continue to rise, the danger level increases. – Climate News Network