A new study led by the University of Maine has found that melting and sublimation caused by anthropogenic climate change is increasingly affecting even the world’s highest peaks, such as Mount Everest’s South Col Glacier, located 8, 020 meters above sea level. According to data from the world’s highest ice core and highest automatic weather stations, the estimated contemporary thinning rates of this glacier are approaching approximately two meters of water per year, now that its peak has turned from snowpack to ice and lost its ability to reflect solar radiation.
This study “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-source climate change,” said study co-author Paul Andrew Mayewski, a glaciologist at the University of Maine. “The answer is a resounding yes, and very significantly since the late 1990s.”
The researchers found that, once South Col Glacier’s ice was regularly exposed, about 55 meters of glacier thinning has occurred in a quarter century. Thus, over the past decades, the glacier lost ice 80 times faster than the nearly 2,000 years it took to form it at the surface. Most likely, the increasing overall surface ice mass loss in the region – marking the transition from permanent snowpack to majority ice cover – was triggered by climate change in the 1950s, and has intensified since the late 1990s.
Model simulations have shown that the glacier’s extreme insolation means that ablation (the loss of surface mass through melting or vaporization) can accelerate by a factor of over 20 once snow cover gives way to ice. While rising temperatures caused most of the sublimation, stronger winds and declining relative humidity have also played important roles in these developments.
“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,” said study lead author Mariusz Potocki, a doctoral student in Glaciochemistry at the University of Maine.
These findings highlight the critical balance snow-covered surfaces provide and the “potential for loss throughout high mountain glacier systems as snow cover is depleted by changes in sublimation — passing from a solid to vapor state — and surface melt driven by climate trends.”
“Everest’s highest glacier has served as a sentinel for this delicate balance and has demonstrated that even the roof of the Earth is impacted by anthropogenic source warming,” concluded the authors.
The study is published in Nature Portfolio Journal: Climate and Atmospheric Science.
By Andrei Ionescu, Earth.com Staff Writer