In a village in Checacupe, in the southern region of Cusco in the Peruvian Andes, there used to be a ceremony to prepare a glacier lagoon to gather water, said Richart Aybar Quispe Soto, a local hospital worker. It was a ritual that revered the apus, the spirits of the mountains and water, he said.

“In my mother’s village,” he said, “the glacier stream, which we call mayucha in Quechua, no longer comes down from the mountain.”

Now, new research shows that the glaciers and water in the central range, closer to the country’s capital, Lima, might face a similar fate.

By 2050, the central range in the Andes might lose between 84 to 98 percent of its glaciers, the study projects. By analyzing seven satellite images to determine changes in glacier coverage from 1990 to 2021 and developing a projection map based on climate characteristics and indexes to identify areas most susceptible to glacial retreat, researchers at the University of Engineering and Technology in Peru found that a total disappearance is expected by 2056. Their results were published last month in the Journal of Water and Climate Change.

“We have to adapt ourselves to the fact that the glaciers, in 50 or 100 years, are going to disappear,” said Pedro Rau, a hydrologist who led the study. Glaciers at lower elevations are particularly vulnerable, he said.

Peru has around 68 percent of the world’s tropical glaciers. These are typically divided into three sections: north, central and south. Glaciers in the northern range of the Peruvian Andes have been extensively studied due to previous natural disasters, like the 1970 Ancash earthquake, which triggered an avalanche. 

In the southern range, around Cusco, they’ve received more international attention, due to the cultural significance of glaciers. But glaciers in the central range, closer to Lima, have not been studied at the same level.

Now, researchers have developed what they describe as a spatial projection map for 2021-2055 to understand what percentage of glacier loss they should expect—and what that means in terms of access to water.

In Peru, glaciers are a strategic water resource for the country’s population, and specifically for Andean communities, the study says.

Around 20 million Peruvians benefit from the water that comes down from the glaciers in some way, according to a 2023 government report. It’s not just about the amount of water, Moschella explained, but about water quality. In the Cordillera Blanca, in the northern range, there’s a more acidic water level due to water running through exposed rocks previously covered by glaciers, according to the government report.

Glacier loss affects millions of people in Lima, and yet, it’s hard to understand because the glaciers are far away, Rau explained, unlike in Cusco, or the northern range, where people like Quispe Soto grew up in much closer proximity to the glaciers. But in the end, he said, “it’s still a national problem.”

Previous studies have focused on understanding the loss and dynamics of glaciers, but this new study focuses on projecting and mapping future glacier conditions. By using these maps, researchers are able to understand the regions most affected by glacier loss, helping craft better decisions around water resource management.

Although glaciers aren’t commonly associated with tropical weather, glaciers can occur in regions where there are high mountain ranges in the tropics, like the Andes. Only a few regions in the world still have tropical glaciers because of their sensitivity to climate change. In lower latitudes, day length does not change much throughout the year, so tropical glaciers tend to melt at a faster rate without a seasonal respite from the sun.

The speed at which tropical glaciers in Peru are melting is “alarming,” said a study published in 2019. In fact, Peru has lost over half of its tropical glaciers in the last 60 years, according to a government report published in October.

The meltdown in Peru is part of the global acceleration of glacier and ice cap decline, with the rate of ice loss nearly doubling to 1.3 trillion tons per year since the 1990s and speeding sea level rise, recent research showed. As a result, at the current pace of global warming, global average sea level would go up 4-5 feet by 2100, a 2022 study says. 

The new study adds to the existing body of research on Peruvian glacier loss as well as to new research on vulnerable regions and forecasts.

“These types of studies contribute to our knowledge of future scenarios,” said Paola Moschella, the director of glacier research at the National Institute for Glacier and Mountain Ecosystem Research (INAIGEM) in Peru, who wasn’t involved in the study. The institute oversees the monitoring of the glaciers at a national level, and is mostly focused on historic glacier loss and risk assessment. These types of studies from researchers outside the institute help researchers there understand future glacier projections, Moschella explained. They also help raise awareness about how the consequences of glacier loss, like lack of water, will intensify, she said.

In regions like Cusco there’s an alarming increase in water shortages in the past couple of years with the government warning of an imminent lack of drinking water throughout 2023. Rau, the study author, was also part of a team of international researchers on a project in Cusco which aimed to better understand and monitor glacier loss and water security.

For people who have experienced the lack of water, like Quispe Soto, the loss of glaciers is alarming in many ways, and not just in terms of water as a resource, but in the significance of glaciers as part of religion and culture. He worries his son won’t experience the glaciers and the water like he did.

“When my father took me as a child to the glaciers, it was all white,” he said. “Today, there’s only black rocks.”