According to a University of Maine-led international research team that analyzed data from the world’s highest ice core and highest automatic weather stations, melting and sublimation on Mount Everest’s highest glacier as a result of human-induced climate change has reached the point where several decades of accumulation are being lost annually now that ice has been exposed.
The exceptional sensitivity of the high-altitude Himalayan ice masses in rapid retreat forewarns of rapidly emerging consequences, which could vary from increased avalanche incidence to diminished glacier stored water capacity, on which more than 1 billion people rely for drinking water and irrigation.
According to UMaine climate scientists Mariusz Potocki and Paul Mayewski, Mount Everest expeditions may be ascending over more exposed bedrock as the highest glaciers melt, potentially making the trek more difficult if the snow and ice cover continues to reduce in the future decades.
The team’s findings are the latest scientific results from the 2019 National Geographic and Rolex Perpetual Planet Everest Expedition, which were published in the journal Nature Portfolio Journal Climate and Atmospheric Science.
The expedition’s scientists, including six from the University of Maine’s Climate Change Institute, researched environmental changes to better understand how rising global temperatures may affect life on Earth.
According to Mayewski, a glaciologist and director of the University of Maine’s Climate Change Institute who was the expedition leader and lead scientist for the Perpetual Planet Everest Expedition, this latest research confirms the heights to which human-caused climate change has reached, and serves as a bellwether for other high-mountain glacier systems and the potential impacts as glacier mass declines.
Climate predictions for the Himalaya suggest continued warming and continued glacier mass loss, and even the top of the Everest is impacted by anthropogenic source warming.
Potocki
“It answers one of the big questions posed by our 2019 NGS/Rolex Mount Everest Expedition whether the highest glaciers on the planet are impacted by human-sourced climate change. The answer is a resounding yes, and very significantly since the late 1990s,” Mayewski says.
The study emphasizes the important balance that snow-covered surfaces provide “Changes in sublimation from a solid to a vapor state, as well as surface melt driven by climatic trends, have the potential to deplete snow cover throughout high mountain glacier systems. Everest’s tallest glacier has served as a sentinel for this delicate equilibrium, demonstrating that anthropogenic source warming affects even the Earth’s roof” In their publication, the researchers make a point.
The researchers used data from a 10-meter-long ice core and meteorological stations, as well as photogrammetric and satellite photography and other records, to investigate the timing and source of major mass loss on South Col Glacier.
They calculated that current thinning rates are approaching 2 meters of water per year now that the glacier has transitioned from snowpack to ice, losing its ability to reflect solar radiation and melting at a faster pace, resulting in rapid melting and increasing sublimation.
Once the ice on the South Col Glacier was frequently exposed, it is estimated that the glacier thinning progressed at a rate of 55 meters each quarter-century, which is more than 80 times faster than the nearly 2,000 years it took to develop the ice at the surface.
According to the researchers, increased overall surface ice mass loss in the region since the 1950s may have caused the switch from permanent snowpack to majority ice cover, with sublimation aided by rising air temperatures. Since the late 1990s, climate change has had the greatest influence on the glacier.
According to model simulations, the region’s exceptional insolation means that if snow cover gives way to ice, ablation loss of surface mass by melting or vaporization can accelerate by a factor of more than 20. While rising air temperatures were the primary source of sublimation, falling relative humidity and stronger winds also played a role.
“Climate predictions for the Himalaya suggest continued warming and continued glacier mass loss, and even the top of the Everest is impacted by anthropogenic source warming,” says Potocki, a glaciochemist and doctoral candidate in the Climate Change Institute who collected the highest ice core on the planet.
Other co-authors of the paper: Tom Matthews, Loughborough University; L. Baker Perry, Appalachian State University; Margit Schwikowski, Paul Scherrer Institut; Alexander M. Tait, National Geographic Society; Elena Korotkikh, Heather Clifford and Sean Birkel, UMaine; Shichang Kang, Chinese Academy of Sciences; Tenzing Chogyal Sherpa, International Centre for Integrated Mountain Development, Kathmandu, Nepal; Praveen Kumar Singh, Indian Institute of Technology Roorkee; and Inka Koch, University of Tübingen.
They were part of an international, multidisciplinary team of scientists, climbers, and storytellers led by the National Geographic Society and Tribhuvan University, and supported by Rolex, that conducted the most comprehensive single scientific expedition to Mount Everest in history, which was led by the National Geographic Society and Tribhuvan University.
The expedition team set up the world’s highest weather stations (at 8,430 and 7,945 meters), collected the world’s highest ice core (at 8,020 meters), conducted comprehensive biodiversity surveys at multiple elevations, completed the world’s highest elevation helicopter-based lidar scan, expanded the elevation records for high-dwelling species, and documented the history of the mountain’s glaciers.
Two of the expedition’s three Guinness World Records have just been set: the highest altitude ice core and the highest altitude weather station on land.
