It’s no surprise that there is worldwide retreat of mountain glaciers in recent decades given rising greenhouse gas emissions and rising temperatures. The concern of losing water from these frozen “storage towers” lies in the fact that ecosystems will suffer, agriculture will be impacted, and, ultimately, humanity will suffer as there will be less water available for the people that depend on it. While glaciers reaching down to lower altitudes are slowly whittling away, what about higher up? Is climate change gracing the tops of Himalayan 8000-meter peaks?

In April/May 2019, the world’s highest ice core was recovered from Mt. Everest. The location? The South Col glacier at 8020 meters, which has an average annual air temperature of -22.6 deg C. The core was drilled to a depth of 10 meters from an estimated total thickness of 30 – 50 meters of ice. Using a combination of ice core analysis, written records, photogrammetry, meteorological records and climate reanalysis for the region, researchers have estimated a thinning of 55 meters (water equivalent) of the South Col glacier in the last 2000 years. 

How is the ice disappearing? It depends on the thickness of the snowpack. Rising air temperatures and exposure to high amounts of sunlight can cause surface temperatures eventually to rise. This can slowly melt the overlying “protective” insulating snow layer, given enough sunny days. If you have a thin snowpack and add in high winds (this is a common occurrence at the South Col), you can expose more bare ice. Bare blue ice is less reflective than white snow and can absorb more of the sun’s energy, leading to high amounts of sublimation: when a solid turns directly to gas, bypassing the liquid phase. The photo is from Ricardo’s Everest expedition in 2017. He’s at the South Col (26,000 ft.). See the patches of bare ice?