Standing on the glacier at the source of the Rhone river, glaciologist Andreas Bauder poses next to a three-metre high pole sticking out of the ice, and gestures above his head.
“This is about the melt of one month,” he says, as fellow scientists drill into the ice. “I’m about two metres tall.”
From the Himalayas to the Andes, faster-melting glaciers spell short-term opportunities – and long-term risks – for hydroelectric power and the engineering and construction industries it drives.
The most widely used form of renewable energy globally, hydro meets more than half Switzerland’s energy needs. As summers dry and glaciers that help drive turbines with meltwater recede, that share may eventually fall.
A study by Lausanne’s EPFL technical university forecast a decline to 46 per cent by 2035 for hydro from around 60 per cent now as precipitation declines and total energy use increases.
In the same way as the Himalayas are “Asia’s water-tower”, Switzerland is the source of Europe’s biggest rivers, supporting agriculture and waterways, and cooling nuclear power stations.
Water trickles down white-blue crevasses and ice cracks and creaks as Dr Bauder, who for Zurich technical university spends about 20 to 30 days a year working on Swiss glaciers, explains that most of the mighty Rhone glacier will be gone by the end of the century.
“Nature can adjust to the circumstances,” he said. “It’s just people who are much more fragile about living conditions.”
More than a billion people worldwide live in river basins fed by glacier or snow-melt.
Glaciers have been retreating dramatically since the end of the Little Ice Age in the 19th century, particularly in the Himalayas where they feed rivers including the Mekong and Yangtze and ensure water and power for fast-growing economies.
A lack of water for hydropower is already “critical” in Bolivia, Peru, Colombia and Ecuador, according to the UN Intergovernmental Panel on Climate Change, which also sees risks to water supplies to southern California from the loss of the Sierra Nevada and Colorado River basin snowpack.
In Europe, 20 per cent of electricity comes from hydro – generating potential that is projected to decrease by the 2070s, falling sharpest in the Mediterranean.
Dr Bauder pointed to an area of stony ground and small lakes beyond the end of Rhone glacier ice field: “When I was a kid, I remember that the glacier was much larger. The glacier tongue was still reaching over this rocky area.”
The Swiss hydroelectric industry is part-funding Dr Bauder’s research, to help it take a long view on new projects in an industry where licenses often run for up to a century.
Other risks researchers have identified include sudden floods from swollen glacial lakes. Demand for more pumping technology and dams is one response in countries which can afford them.
Experts stress that forecasts so far ahead are highly uncertain, particularly in predicting precipitation, and note that some regions may even benefit.
“With climate change there will be some areas in the world with more precipitation year round,” said Petra Doell, a professor of hydrology at the University of Frankfurt and a member of the UN climate panel.
“That will mean more hydropower generation even if glaciers melt.”
For example Norway, which generates almost 100 percent of its power from hydroelectricity, is likely to get more rain and snow because of climate change even as glaciers retreat.
But if glaciers do disappear, one main impact will be lower river flows in dry seasons – when irrigation is often needed for crops. That would particularly threaten people in the world’s biggest rice-growers, China and India.