Natural and societal consequences of climate-forced changes of Jostedalsbreen Ice Cap
RECENT RETREAT OF NIGARDSBREEN ALTERS LOCAL WEATHER AND CLIMATE
by Kristine Flacké Haualand, July 31, 2025
While the impact of climate change on glacier retreat is well documented, there is less knowledge of how retreating glaciers feedback on climate. Findings from a new JOSTICE publication in Journal of Geophysical Research: Atmospheres demonstrate that the microclimate near Nigardsbreen changes with recent glacier retreat, with a particular impact on glacier winds.
Using a weather and climate model with glacier outlines of Nigardsbreen from 2006 and 2019, we have compared the impact of glacier extent on glacier winds. During these 13 years, the front of Nigardsbreen retreated from nearly touching the proglacial lake Nigardsbrevatn to almost 1 km up-valley. This recent retreat has opened a forefield (see image below) that gets much warmer than the surrounding ice and lake surfaces during summer. As a result, the down-valley extension of Nigardsbreen is no longer a cold lake but instead a growing area of heated bedrock.
Nigardsbreen and Nigardsbrevatn in September 2023 (drone image: Sigurd D. Nerhus).
As glacier winds are driven by local temperature contrasts, these recent surface changes provide modified forcings for the glacier wind system. Our model simulations show that the recent retreat of Nigardsbreen weakens glacier winds and alters the location and strength of convection, which may influence local cloud patterns. In some weather conditions, glacier retreat also modifies mountain wave propagation that occurs several kilometres above the glacier surface.
Along with glacier retreat, proglacial lakes often warm, potentially leaving important changes in surface temperature patterns near the glacier. We therefore also tested the sensitivity of glacier winds to lake surface temperature and found that glacier winds weaken with a warmer lake.
These results highlight the need for an accurate representation of glacier extent and glacial lakes when evaluating climate change in glacial regions.