Arctic open-water periods are projected to lengthen dramatically by 2100

• Published in: Communications Earth & Environment
• Main Authors: Crawford, Alex, Stroeve, Julienne, Smith, Abigail, Jahn, Alexandra
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2021
• Subjects: General Earth and Planetary Sciences; General Environmental Science; Arctic; Climate change; Global warming; Sea ice
• Online Access: http://dx.doi.org/10.1038/s43247-021-00183-x; http://www.nature.com/articles/s43247-021-00183-x.pdf; http://www.nature.com/articles/s43247-021-00183-x

Abstract The shrinking of Arctic-wide September sea ice extent is often cited as an indicator of modern climate change; however, the timing of seasonal sea ice retreat/advance and the length of the open-water period are often more relevant to stakeholders working at regional and local scales. Here we highlight changes in regional open-water periods at multiple warming thresholds. We show that, in the latest generation of models from the Coupled Model Intercomparison Project (CMIP6), the open-water period lengthens by 63 days on average with 2 °C of global warming above the 1850-1900 average, and by over 90 days in several Arctic seas. Nearly the entire Arctic, including the Transpolar Sea Route, has at least 3 months of open water per year with 3.5 °C warming, and at least 6 months with 5 °C warming. Model bias compared to satellite data suggests that even such dramatic projections may be conservative.