Rising global temperatures pose growing threats to the glaciers found in the Himalayan mountains. Research shows that the highest peaks in the world are at risk of losing almost 80% of their volume by the end of the century, with the potential to cause flooding and water shortages for 2 billion people. A recent study found that the Himalayan glaciers fight back to preserve themselves and the surrounding ecosystems.
Natural Self-Preservation Mode
Experts have previously documented an elevation-dependent warming effect observed in the Himalayan mountains. They found that the peaks "felt" the effects of global warming stronger than the rest of the landscape and warmed up faster. However, a high-altitude climate station located at the base of Mount Everest in Nepal observed that the surface air temperature averages do not increase but remain stable instead.
This mystery was finally solved by an international team of researchers from the Institute of Science and Technology Austria (ISTA) and the National Research Council of Italy (CNR). The group, led by Professor Francesca Pellicciotti, discovered that global warming triggers a cooling reaction in the glaciers, causing katabatic winds (cold winds) to flow down the slopes.
While the minimum temperatures rise steadily, the maximum surface temperature in summer drops consistently. Upon examining the collected data, the researchers realized that the overall temperature averages remain stable for a simple reason.
According to Pellicciotti, the glaciers react to the warming climate by increasing their temperature exchange with the surface. This happens through an increased temperature difference between the warmer environmental air above the glacier and the air mass in direct contact with the glacier's surface.
This temperature difference increases turbulent heat exchange at the glacier's surface and stronger cooling of the surface air mass. As a result, the dry and cool surface air masses get denser and flow down the slopes into the valleys, cooling the lower parts of the glaciers and the surrounding ecosystems.
How Long Can the Glaciers Fight Back?
Experts believe that katabatic winds serve as the response of healthy glaciers to global warming and that this mechanism can help preserve the permafrost and surrounding vegetation.
The glaciers on the southern Himalayan slopes represent the "accumulation-ablation glaciers." This type of glacier accumulates mass at high elevations from the summer monsoons of the Indian subcontinent while losing mass from continuous melting at the same time. However, it was found that the katabatic winds are currently shifting this balance, as the colder air masses that flow down from the glaciers lower the altitude where precipitation happens.
As a result, the glaciers miss a key mass input while they continue to melt. This means that the perceived cool temperatures that flow down from glaciers are an emergency reaction to global warming instead of an indicator of long-term glacier stability.
Glaciers are approaching their preservation tipping point in some places, but scientists are not losing hope. While glaciers may not preserve themselves forever, they can still preserve the environment around them for some time. Thus, experts call for more multidisciplinary studies to unite efforts toward understanding the effects of global warming. Such efforts could effectively change the course of climate change caused by human activity.
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