A peer-reviewed modelling study projects greater glacier loss when weather is represented daily rather than through monthly averages. Short hot spells, rain instead of snow and changes in exposed ice alter the calculations. The comparison covers most global glacier volume and increases the modelled sea-level contribution, while the size of the difference varies by region.
Science··Evening
Weather changes the projected ice balance
A daily version of the Global Glacier Evolution Model, known as GloGEM, projected greater glacier losses than its monthly counterpart in one peer-reviewed Nature Communications study. The global sample contained 12,571 glaciers. Each exceeded 5 square kilometres in area; together they held about 94 per cent of glacier volume. Both versions used a common geometry framework and calibration against measured recent mass changes, allowing researchers to compare temporal resolution within one model family.[1]
Short hot spells escape monthly averages
The daily calculation follows extreme melting days, shifts between rain and snow, and the exposure of darker ice as snow disappears. Monthly averaging smooths these processes. For validation, researchers drew on 175 glaciers with 4,037 annual observations of mass balance. Average accuracy improved modestly, with clearer differences during extreme years. Responses varied by region; Iceland showed a reversed difference linked to warm precipitation events and their effects on calibration.[1]
Sea-level estimates also increase
For global mean sea level, the daily calculation implied an extra 20–33 millimetres compared with the monthly version. Researchers tested five climate models under several emissions scenarios. The difference remained within the spread across climate models. These are scenario-based projections, covering glaciers rather than the main Greenland and Antarctic ice sheets. Most small glaciers were excluded, runoff was assumed immediate, and the daily version took about ten times as much computation on the tested workstation.[1]
