A Svalbard glacier once survived a warmer climate

A new study reports that Åsgardfonna, an ice cap on Svalbard covering 1,230 km2, held out through a period about 9,500 years ago when the planet was warmer than it is now, and may even have grown. It is one of the largest ice caps in the Norwegian archipelago, the Barents Observer reported. That period is called the Holocene Thermal Maximum. Summer temperatures were around 8 °C higher than now, and the climate was wetter as well.

The researchers link the glacier's endurance to possibly stronger snowfall caused by the loss of sea ice. When ice no longer covers the Arctic Ocean, the atmosphere receives much more heat and moisture than usual. The study adds that in comparable settings, greater precipitation in the future could slow the retreat of glaciers.

To reach this result, the team analysed several kinds of sediment that had settled in lakes receiving meltwater from the glacier. According to the study, such material collects in these lakes and keeps an unbroken record of how glaciers changed over time.

The Arctic is heating up faster than the rest of the world, and a main sign, visible from satellites, is the shrinking extent of Arctic sea ice. The monthly extent was the lowest on record for February this year. Elsewhere, glaciers are shrinking fast too, which raises sea levels. In Norway, some glaciers have pulled back by as much as 2.5 km since the start of the last century.

The study points to some glaciers possibly being more resilient than assumed, while the future remains uncertain because reliable observations are lacking, the Barents Observer reported. The study states that weather station data from the Arctic are few, and that snowfall is frequently under-measured because wind carries snow away from the gauges. Simulations therefore come out lower than the precipitation increases that have been observed, and they differ on how future change will be spread across the seasons.