The Arctic-Subarctic sea ice system is entering a seasonal regime: Implications for future Arctic amplification

• Published in: Scientific Reports
• Main Authors: Haine, Thomas W. N., Martin, Torge
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Research 2017
• Subjects: Antarctic; Arctic; The Antarctic; Antarc*; Climate change; Sea ice; Subarctic
• Online Access: https://oceanrep.geomar.de/id/eprint/38856/; https://oceanrep.geomar.de/id/eprint/38856/1/s41598-017-04573-0.pdf; https://oceanrep.geomar.de/id/eprint/38856/2/41598_2017_4573_MOESM1_ESM.pdf; https://doi.org/10.1038/s41598-017-04573-0

The loss of Arctic sea ice is a conspicuous example of climate change. Climate models project ice-free conditions during summer this century under realistic emission scenarios, reflecting the increase in seasonality in ice cover. To quantify the increased seasonality in the Arctic-Subarctic sea ice system, we define a non-dimensional seasonality number for sea ice extent, area, and volume from satellite data and realistic coupled climate models. We show that the Arctic-Subarctic, i.e. The northern hemisphere, sea ice now exhibits similar levels of seasonality to the Antarctic, which is in a seasonal regime without significant change since satellite observations began in 1979. Realistic climate models suggest that this transition to the seasonal regime is being accompanied by a maximum in Arctic amplification, which is the faster warming of Arctic latitudes compared to the global mean, in the 2010s. The strong link points to a peak in sea-ice-related feedbacks that occurs long before the Arctic becomes ice-free in summer.