Sea ice-free Arctic during the last interglacial supports fast future loss

• Published in: Nature Climate Change
• Main Authors: Guarino, Maria-Vittoria, Sime, Louise C., Schroeder, David, Malmierca-Vallet, Irene, Rosenblum, Erica, Ringer, Mark, Ridley, Jeff, Feltham, Danny, Bitz, Cecilia, Steig, Eric J., Wolff, Eric, Stroeve, Julienne, Sellar, Alistair
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Publishing Group 2020
• Subjects: Arctic; Climate change; Sea ice
• Online Access: https://centaur.reading.ac.uk/91701/; https://centaur.reading.ac.uk/91701/1/18887_2_merged_1594159790.pdf

The Last Interglacial (LIG), a warmer period 130-116 ka before present, is a potential analog for future climate change. Stronger LIG summertime insolation at high northern latitudes drove Arctic land summer temperatures 4-5 ◦C higher than the preindustrial era. Climate model simulations have previously failed to capture these elevated temperatures, possibly be- cause they were unable to correctly capture LIG sea-ice changes. Here, we show the latest version of the fully-coupled UK Hadley Center climate model (HadGEM3) simulates a more accurate Arctic LIG climate, including elevated temperatures. Improved model physics, in- cluding a sophisticated sea-ice melt-pond scheme, result in a complete simulated loss of Arctic sea ice in summer during the LIG, which has yet to be simulated in past generations of mod- els. This ice-free Arctic yields a compelling solution to the longstanding puzzle of what drove LIG Arctic warmth and supports a fast retreat of future Arctic summer sea ice.