Everest glacier has lost 2,000 years of ice since the 1990s
Even the glaciers on Mount Everest aren’t safe from climate change, new research suggests. In a record-setting study, a team of scientists scaled the world’s highest peak to monitor the mountain’s highest altitude glacier, the South Col glacier, standing nearly 8,000 metres above sea level, for signs of climate-related ice loss. After installing the two highest weather stations on Earth and collecting the world’s highest ice core from the glacier, the team found that South Col is losing ice roughly 80 times faster than it took for the ice to accumulate on the glacier’s surface.
The team’s core analysis showed that ice that took 2,000 years to form on the glacier has completely melted away since the 1990s, and that the glacier is currently losing several decades worth of ice accumulation every year. “[This] answers one of the big questions posed by our [expedition] – whether the highest glaciers on the planet are impacted by humansource climate change,” said Paul Mayewski, a glaciologist at the University of Maine and director of the University’s Climate Change Institute. “The answer is a resounding yes, and very significantly since the late 1990s.” The glacier’s rapid decline could have serious impacts on the mountain and those who live near it. The melt may result in more avalanches on Everest, or expose more bedrock, making the terrain more treacherous for climbers.
On a recent expedition, ten researchers climbed to the base of South Col and installed two weather detection stations, one at 8,430 metres and the other at 7,945 metres above sea level. The team also drilled a ten-metre ice core from the glacier to reveal how the glacier ice’s thickness has changed over time. With this data in hand, the team ran computer models to simulate the glacier’s growth and retreat over thousands of years. The team concluded that South Col has lost more than 54 metres of ice thickness in the last 25 years. While the effects of wind and changes in humidity may have contributed to this ice loss, human-induced climate change is the overwhelming cause.
In fact, the team found that South Col may have begun thinning from climate change as early as the 1950s. However, by the 1990s, the melt rate accelerated significantly when the glacier’s snowpack, outer layers of snow that accumulate over time, finally disappeared, exposing the glacier’s raw ice to the Sun’s radiation. Now missing its shield of white ice to reflect the Sun’s rays, South Col will likely rapidly retreat. Ultimately, while South Col is just one glacier among many in the Himalayas, its position at the top of the world shows that no ice mass is safe from climate change. Brandon Specktor