A Seasonally Delayed Sea Ice Response and Arctic Amplification During the Last Glacial Inception

Abstract The last glacial inception (LGI) marks the transition from the interglacial warm climate to the glacial period with extensive Northern Hemisphere ice sheets and colder climate. This transition is initiated by decreasing boreal summer insolation but requires positive feedbacks to stimulate t...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Shan Xu, Uta Krebs‐Kanzow, Gerrit Lohmann
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2024
Subjects:
climate models
glacial inception
sea ice
paleoclimate calendar
Geophysics. Cosmic physics
QC801-809
albedo
Sea ice
Online Access:https://doi.org/10.1029/2023GL107927
https://doaj.org/article/e6a8a98890be42e1964fda9e20320f6a
Description
Summary:Abstract The last glacial inception (LGI) marks the transition from the interglacial warm climate to the glacial period with extensive Northern Hemisphere ice sheets and colder climate. This transition is initiated by decreasing boreal summer insolation but requires positive feedbacks to stimulate the appearance of perennial snow. We perform simulations of LGI with climate model AWI‐ESM‐2.1, forced by the astronomical and greenhouse gas forcing of 115,000 years before present. To compare with the preindustrial (PI) simulation, we use a consistent definition of the seasons during the LGI and the PI and evaluate model output on an angular astronomical calendar. Our study reveals a prominent role of the sea‐ice albedo feedback to amplify the delayed climate signal at polar latitudes. Through a radiative budget analysis, we examine that the ice‐albedo feedback exceeds the shortwave radiative forcing, contributing to the cooling and high latitude snow built‐up during LGI.

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