A Glacier's Shape Speeds Up Its Own Melting, Russian Scientists Find
Glaciers do not melt at a rate set by the climate alone. Researchers at the Arctic and Antarctic Research Institute (AARI) in St. Petersburg have found that the shape of an ice mass also plays a part, and that leaving it out of the calculation can distort climate estimates.
“The rate at which glaciers melt depends not only on climate warming, but also on their shape and size. Without correcting for the ‘geometric’ factor, climate estimates based on temperature change data risk being inaccurate,” the institute’s press service said.
Sinking into Warmer Air
As a glacier melts, its surface drops to lower elevations, where the air is warmer. The ice then melts faster even if the weather stays the same. If calculations ignore this, the extra loss ends up counted as part of the warming signal.
“A glacier is a living, constantly changing object. As it melts, its surface drops lower and lower, and down there the air is warmer, so the ice starts melting even faster, even if the weather outside hasn’t changed by a single degree. For now the effect is small, but if we don’t account for it when analyzing longer observation records, we risk mistaking part of the glacier’s own ‘geometric’ history for a climate signal that isn’t really there,” said Anton Terekhov, a senior researcher at AARI.
Twelve Years on Svalbard
Svalbard is one of the fastest-warming places on Earth. A 2022 study by the Norwegian Meteorological Institute found that parts of the archipelago and the northern Barents Sea are warming up to seven times faster than the global average.
AARI’s findings rest on long-term monitoring of two valley glaciers there, Aldegonda and Vestre Grønfjordbreen. Between 2013 and 2025, the two glaciers lost roughly 18–20 meters of water equivalent.
The team calculated the glaciers’ mass balance in two ways. The first used the actual surface shape, updated each year. The second assumed the glaciers kept the geometry they had in 2008. Comparing the two showed how much of the loss came from the glaciers themselves rather than from the weather.
Because more of each glacier now sits at lower, warmer elevations, Aldegonda loses an extra 1–2 percent of its ice each year and Vestre Grønfjordbreen an extra 0.5–1 percent, on top of what the climate alone would explain. Over the past two decades, this has been too small to skew the overall climate assessment, but it grows with the length of the record and with the speed of melting.
AARI proposes applying the same method to glaciers elsewhere. Satellite digital elevation models now cover the entire Arctic and Antarctic, so the researchers say the calculation can be repeated for almost any glaciated region.
Source: TASS (in Russian)