ABRUPT Arctic Climate Change

During the last glacial, a series of abrupt climate change events took place. Over Greenland, atmospheric temperature shifts of about 10±5°C, from cold to relatively warm, occurred within decades. A link is seen between changes in the sea ice extent in the southern Nordic Seas and these climate shifts. However, it is still not known how far north the sea ice cover disappeared when it broke up in the southern Nordic Seas. Or how different the timing and duration of the events were in the northernmost Nordic Seas relative to the southern Nordic Seas, how the stability of the water column was impacted, or what may have initiated abrupt changes in the full ocean basin. Through ABRUPT, we will provide reconstructions of sea ice, ocean and climate conditions in the Fram Strait over a couple of these abrupt events. These reconstructions, and reconstructions from other parts of the Nordic Seas, will be used in combination with climate model data to investigate the abrupt climate changes that took place, and why. Furthermore, the ice-covered Nordic Seas of the cold glacial periods share some characteristics with the present-day Arctic Ocean; a cold, fresh water layer that stabilize the sea ice cover and the underlying layer of Atlantic water that brings warm and salty water masses to the interior of the ocean basin, where it recirculates underneath the cold, fresh water mass. Over the last decades, abrupt warming has occurred around the Fram Strait, comparable to the rapidity of the glacial temperature changes that occurred over Greenland during the glacial. ABRUPT will evaluate if understanding the abrupt glacial climate changes may be of relevance for understanding the risk of similar changes in the future Arctic.