Accounting for daily weather variability may give more realistic estimation of glacier melt: Study

New Delhi: A new study shows that accounting for daily weather variability could lead to a more realistic estimation of glacier melt, revealing that glaciers around the world could be losing ice faster than previously thought.

Researchers, led by those at ETH Zurich in Switzerland and the Vrije Universiteit Brussel, Belgium, say simulations of glacier melt resulted in a greater projected ice loss by the end of the century.

The findings, published in the journal Nature Communications, highlight the importance of short-lived weather events, such as the exceptional heatwaves and extreme melt seasons recently observed in several glacierised regions around the globe, the team said.


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"Glaciers don't respond to monthly averages, but to the weather they experience every single day," lead author Lander Van Tricht, from ETH Zurich, explained.

"A heatwave lasting only a few days can cause enormous amounts of ice to melt. By averaging weather conditions over an entire month, we risk underestimating the impact of these extreme events," Van Tricht said.

Similarly, whether heavy precipitation falls as rain or snow can strongly influence glacier accumulation and runoff, particularly when temperatures fluctuate around the freezing point, the researchers say.

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By resolving the day-by-day processes, the model better captures rapid transitions between snow-covered and exposed ice surfaces, as well as the associated changes in melting, they say.

To better capture the processes, the researchers extended the Global Glacier Evolution Model (GloGEM) to operate at a daily resolution, applying it to more than 12,500 glaciers -- representing 94 per cent of the world's glacier ice volume.

Compared with the traditional monthly approach, the enhanced model better reproduces observed glacier mass loss, particularly during exceptional melt years, including 2022 in the European Alps, the researchers found.

The findings show that effects of daily weather variability accumulate over time.

When projected into the future, the daily model largely predicted a faster glacier retreat and greater ice loss than its monthly counterpart, particularly in regions where melting is strongly influenced by short-term temperature fluctuations.

The result also translated into a larger projected contribution to global sea-level rise. The daily model used in the study projected a 5-10 per cent higher 21st century contribution from glaciers to sea-level rise than its monthly counterpart, the researchers found.

"Our findings suggest that existing global projections, which typically rely on monthly climate forcing, may underestimate how quickly glaciers will lose ice in a warming world," Van Tricht says.

"It is not only the gradual rise in temperature that matters. Extreme melt events, like those we have recently witnessed in the European Alps and other regions, can have lasting consequences for glaciers. Capturing these events is therefore essential to better understand their future," the lead author says.

Beyond glacier retreat and sea-level rise, the study also reveals important changes in the timing and intensity of glacier meltwater runoff, with implications for downstream water resources, the researchers say.