High, high up in the Andes mountains above Chile’s capital, at the foot of the glaciers that date from the last ice age, the temperatures were almost balmy this summer. That threatens long-term water supplies to the city of seven million spread out on the plain below.
At the Olivares Alfa glacier, 4,420 meters above sea level, temperatures rose above 10 Celsius on several days in January and rarely fell below zero, said Andres Rivera, a glaciologist at the Center of Scientific Studies in Valdivia.
“It is not rare to have above-zero temperatures during summer, but high temperatures day and night, for several days in a row, that was unprecedented,” Rivera said.
“Glaciers are really vulnerable and yet they have managed to survive all sorts of climate events for 10,000 years,” said Francisco Ferrando, a geography professor at Universidad de Chile in Santiago. “Global warming is accelerating and the change is being felt strongly up in the mountain, so right now glaciers are in survival mode.”
It is unknown exactly how much of Santiago’s water supply depends on glaciers, but one thing is clear, Chile needs to invest in new reservoirs. For now, the city that can go five months without any rain is supplied by the snows and ice on the mountains that act as a natural reservoir.
“Glaciers will last another century, or a century and a half, depending on the amount of ice, the altitude and the extent of each one,” Ferrando said. “Right now the concern is that they last as long as possible so the country can adapt to life without glaciers in a few decades’ time.”
The Echaurren Norte glacier above the Laguna Negra reservoir has shrunk in height by the equivalent of 20 meters of water over the past 40 years, according to the government’s Water Directorate. That standard measure for glaciers means that the height of the ice has been reduced by about 25 meters since 1976.
That was before this year’s heat wave, with the glacier probably shrinking further in the past 12 months.
“As glaciers melt and rains increase in winter, there will be more water in rivers over the short term,” Rivera said. “But we will also be seeing an increase of risky geological phenomenon such as landslides and mudslides.”
At least five people were killed in February when a deluge of water, rocks and uprooted trees poured through the town of San Jose de Maipo with little warning.
The situation may be even more critical in neighboring Bolivia where glaciers have shrunk by 43 percent in 20 years, according to research by Manchester Metropolitan University. The study said new lakes have appeared as a consequence of the melting and at least 25 of them are at risk of causing floods or mudslides.
At some point soon, Latin America needs to prepare for life without glaciers.