Study Finds Daily Weather Variations Key to More Accurate Glacier Melt Estimates

NEW DELHI, Oct 20: Glaciers worldwide could be losing ice faster than previously estimated, as conventional climate models may fail to capture the full impact of short-lived heatwaves and other daily weather fluctuations, according to a new study.

Researchers from ETH Zurich in Switzerland and Vrije Universiteit Brussel in Belgium found that accounting for day-to-day weather conditions produced higher projections of glacier retreat and ice loss by the end of the 21st century.

Published in the journal Nature Communications, the study highlights how extreme weather events, including intense heatwaves and unusually severe melting seasons, can significantly influence the long-term stability of glaciers.

“Glaciers don’t respond to monthly averages, but to the weather they experience every single day,” said lead author Lander Van Tricht of ETH Zurich.

He explained that even a heatwave lasting a few days can trigger substantial ice loss. Averaging temperatures and other weather conditions over an entire month may therefore obscure the effects of these extreme events and lead to underestimations of melting.

The researchers also pointed to precipitation as an important factor in glacier evolution. When temperatures fluctuate around the freezing point, whether precipitation falls as rain or snow can substantially affect ice accumulation, surface melting and downstream water flows.

To address these limitations, the team enhanced the Global Glacier Evolution Model (GloGEM) to simulate glacier processes at a daily resolution rather than relying on monthly climate averages.

The upgraded model was applied to more than 12,500 glaciers, representing approximately 94 per cent of the world’s glacier ice volume.

Comparisons with the traditional modelling approach showed that the daily-resolution system reproduced observed glacier mass loss more accurately, particularly during years marked by exceptionally intense melting. One example was 2022, when glaciers in the European Alps experienced severe ice loss.

The researchers found that the effects of daily weather variability extend beyond individual melting seasons. Repeated periods of intense melting can accumulate over time, influencing the overall rate at which glaciers shrink.

When the improved model was used to project future changes, it generally predicted faster glacier retreat and greater ice loss than the monthly approach, particularly in regions where melting responds strongly to short-term temperature variations.

The difference was also evident in estimates of global sea-level rise. According to the study, the daily model projected a contribution from glaciers that was 5–10 per cent higher during the 21st century than the estimate produced by its monthly counterpart.

Van Tricht said the findings indicate that existing global projections based on monthly climate data could underestimate the speed of glacier loss as the planet warms.

He emphasised that long-term temperature increases are not the only factor determining glacier survival. Short-lived extreme melting events can leave lasting effects, making it essential for climate models to capture rapid changes in weather conditions.

The study also examined the implications for glacier-fed rivers and downstream communities. Changes in the timing and intensity of meltwater runoff could affect the availability of water for households, agriculture and other economic activities.

Glaciers act as important natural reservoirs, storing water as ice and releasing it as temperatures rise. Their seasonal meltwater supports river systems in many mountainous regions, particularly during warmer and drier periods.

As glaciers retreat, changes in the volume and timing of runoff can create challenges for communities that depend on these water supplies. More accurate projections could help researchers and policymakers better understand future risks to water security.

The findings underline the importance of improving the temporal resolution of climate simulations. By capturing daily fluctuations in temperature and precipitation, scientists can develop a clearer picture of how glaciers respond to extreme events and long-term warming.

The researchers said that incorporating these processes into global assessments could improve estimates of future ice loss, sea-level rise and changes in freshwater availability.

The study adds to growing scientific evidence that extreme weather events can have consequences extending well beyond the periods in which they occur. For glacier research, accounting for these short-term variations could prove essential to producing more reliable forecasts of changes in the world’s ice reserves.