Why did the Jakobshavn Isbræ ice stream in West Greenland retreat under a cold climate period called the Younger Dryas?
Why did the Jakobshavn Isbræ ice stream in West Greenland retreat under a cold climate period called the Younger Dryas?
A research article, published in Nature Communications, shows that a warmer ocean surface in central-eastern Baffin Bay triggered the ice retreat during this cold period. The Younger Dryas period occurred 12,900-11,700 years ago and interrupted the atmospheric warming after the last ice age.
Diatoms reveal warm ocean surface in central-eastern Baffin Bay
The published study uses marine fossil diatoms preserved in the sediments to reconstruct past sea surface conditions, including sea surface temperatures, sea ice variability and ocean currents. Diatoms were studied from a ca. 7-meter long sediment core recovered from the ocean floor in 2008. Such sediment cores are windows to the past climate. According to the study, the warmer sea surface temperatures and less-extensive sea ice cover during the Younger Dryas were caused by an enhancement of warmer Atlantic-sourced water inflow to Baffin Bay and increased solar insolation in the Northern Hemisphere.
Read more at University of Helsinki
Image: Mimmi Oksman uses the microscope to study diatoms that live in the ocean´s uppermost water layer and are deposited to sediments as they die. Image Credit: Mimmi Oksman
