Melting glaciers leave a flood of problems for Peru

Screen Shot 2017-08-07 at 7.43.22 PM.pngAbove: An Andes mountain range and a cross headstone are seen from Cementerio Municipal De Huaraz in Huaraz, in the Ancash region of Peru, on July 13.

LAKE PALCACOCHA, Peru

After a day of bright sunshine, a chunk of ice the size of a dump truck broke off the glacier on Mount Pucaranra a few weeks ago. It plunged into the lake below and kicked up a wave nine feet high.

Victor Morales, a small, catlike man with a tattered ski cap who is the lake’s solitary watchman, scrambled up to a stone hut on the side of the mountain and got on the radio. The wave had damaged an emergency drainage system meant to reduce the volume of the lake. But to his great relief, the earthen dam holding back the water was intact.

 

“It wasn’t a big avalanche,” Morales said.

Lake Palcacocha is a mile long and 250 feet deep, and the effect of a large avalanche would be similar to dropping a bowling ball in a bathtub. Modeling scenarios predict a 100-foot wave so powerful it would blow out the dam. Three billion gallons of ice water would go roaring down the mountain toward the city of Huaraz, burying its 200,000 residents under an Andean tsunami of mud, trees and boulders.

So far, it’s not going very well.

“For countries like Peru that are trying to climb out of poverty, there are major social, cultural and economic obstacles to adaptation,” said Nelson Santillán, a researcher at Peru’s national water authority. “Identifying risks is one thing, but doing something about them is another.”

In the weeks since President Trump announced the United States would renege on its commitment to the Paris climate accord, scientists have pointed to new signs the planet is edging closer to a precipice. Maximum temperature records continue falling. New cracks are opening at the polar ice caps.

Peru’s high-altitude glaciers are tiny by comparison, but millions of people depend on their runoff for water, food and hydroelectricity.

Some of Peru’s glaciers have lost more than 90 percent of their mass. While much of the water trickles harmlessly down the mountainside, in places like Lake Palcacocha, it is pooling in great big puddles of melted ice. Many of these new lakes are held back by glacial moraines, which are essentially mounds of compressed sediments. They may be structurally weak, and as the volume of water pushing on them increases, some will collapse.

“We have glaciers across 19 — no, 18 — mountain ranges,” said Marco Zapata, a top scientist at Peru’s institute for glacier research, correcting himself to reflect the latest monitoring data.

“They’re all shrinking.”

For Peruvian authorities, this is becoming more of an engineering problem than an environmental lament. Without reliable glacial runoff, the country’s water and irrigation systems will need to be retooled. New dams and reservoirs will be needed to more effectively store water. Investments in agriculture and other water-intensive industries will need to be recalculated.

“The glacier used to come down to there,” said Tomás Rosario, 45, who farms in the shadow of 22,000-foot Huascaran, Peru’s highest peak. He pointed at a ridge above his village, where bare rock was exposed. “Now the snow is gone and we’re running out of water.”

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