How scientists turned the world’s highest mountain into a climate laboratory

A diverse array of experts braved the elements on Everest to unlock clues to our planet's dramatic warming.

As part of the National Geographic and Rolex Perpetual Planet Everest Expedition, a team of scientists and Sherpa guides sets out to collect information about glacial change in the Himalayas. By extracting ice cores from the highest glacier in the world, the team has begun to uncover details about climate change that have—until now—been hidden in this hard-to-reach ice.

How scientists turned the world’s highest mountain into a climate laboratory

A diverse array of experts braved the elements on Everest to unlock clues to our planet's dramatic warming.

As part of the National Geographic and Rolex Perpetual Planet Everest Expedition, a team of scientists and Sherpa guides sets out to collect information about glacial change in the Himalayas. By extracting ice cores from the highest glacier in the world, the team has begun to uncover details about climate change that have—until now—been hidden in this hard-to-reach ice.

This article was supported by Rolex, which is partnering with the National Geographic Society to shine a light on the challenges facing the Earth’s critical life-support systems through science, exploration, and storytelling.

The end of spring is usually the time to assess the annual Mount Everest climbing season, but this year, because of COVID-19, the mountain was unusually quiet. Nepal banned all expeditions on its side. China banned foreign mountaineers but allowed Chinese nationals to climb from the Tibet side, including a team of surveyors attempting to remeasure the mountain’s height in the wake of the 2015 earthquake.

But while most of the climbing world took a break from Everest, a group of scientists in labs spread across Europe, the U.S., and Nepal have been working on the mountain “remotely”—analyzing a trove of ice, snow, water, and sediment samples they collected last spring as part of the National Geographic and Rolex Perpetual Planet Everest Expedition. The project's goal was to turn the world’s highest mountain into a giant climate laboratory.

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Climate scientist Paul Mayewski holds a section of one of the ice-cores extracted from the upper slopes of Mount Everest. The cores were transported to labs at the University of Maine where portions will be melted and analyzed for clues to changes in the environment over time.

During April and May last year, a multi-disciplinary team of more than 30 biologists, glaciologists, geologists, meteorologists, and geographers fanned out across Everest’s southern flank, conducting fieldwork high on the mountain, as well as across the Khumbu Valley.“We believe the best way to do science on Everest isn’t just to do one kind of science, but do many kinds of science,” says Paul Mayewski of the University of Maine, the leader of the effort, which saw the National Geographic Society partner with Tribhuvan University and the Government of Nepal.

Each individual study promises a unique snapshot of the mountain’s climate—past, present, and future. Ice cores and lake sediment cores will provide a record of what the environment was like going back thousands of years. Snow and water samples give a look at what’s happening on the mountain, today, including the future of the glaciers, which serve as crucial water sources for large downstream populations. The team also installed a network of automated weather stations, which will document upcoming weather trends for years to come.

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Climate scientist Mariusz Potocki (at left) used a special drill to take a core sample of the ice at 26,312 feet on Everest’s South Col. His team later hauled some 30 pounds of ice samples down the mountain. Similar to a tree’s growth rings, each layer of an ice core contains a record of chemicals present in the atmosphere when the water was frozen.

One of the most daunting assignments fell to Mayewski’s colleague Mariusz Potocki, who hoped to drill ice cores at several elevations on the mountain, including at the South Col (25,938 feet) and the summit of Everest (29,035 feet). The job required a specially modified drill system powered by batteries, and a crack team of Sherpas to guide him up the mountain and help carry down the heavy sections of ice. Then, the team had to figure out how to keep the cores frozen during their long journey back to the University of Maine’s laboratory for analysis.

Although Potocki was forced to abandon his summit attempt due to the crowds of recreational climbers, he succeeded in taking the highest ice core ever recovered, at just above Camp Four—26,312 feet above sea level. “This ice, it’s obviously very old... I think it has many stories to tell,” Potocki says.

“The ice doesn’t lie,” Mayewski says. “The very idea that the highest part of the planet has been impacted by human activity ought to be a real wakeup call for everybody.”

The results from the various studies will be published in peer-reviewed journals in the coming months. A documentary chronicling the scientists’ efforts to build the world’s highest weather station and collect the other data and samples amid Everest’s extreme conditions will air the National Geographic Channel June 30 at 10/9c.