Arctic Sea Ice Crossed Major Threshold of Loss in 2007, Becoming Weaker and More Vulnerable

Nature, 15 March 2023

An examination of decades of measurements from the Fram Strait concluded that Arctic sea ice crossed an essentially irreversible threshold of loss between 2005-2007, when fully half of the Arctic’s thick multi-year ice disappeared — and has never recovered. Even today, less than one-tenth of Arctic sea ice passing through the Fram Strait is over 4 meters thick. The unprecedented lows reached in 2005, and again in 2007, marked a transition point across the Arctic Basin, shifting this ice-capped environment to a thinner, more vulnerable landscape. This shift to thinner ice makes it easier for large sheets of sea ice, or “ice floes” to enter the Strait and melt in warm Atlantic waters, preventing the winter growth of sea ice from lasting through the summer. Overall, ice floes now spend one-third less time in the Arctic since 2007. These findings highlight the existence of thresholds and “non-linear” changes in cryosphere, and the very long-lasting impacts of current global warming on the world’s ice stores.

https://www.nature.com/articles/s41586-022-05686-x