The ice is melting everywhere.
This spring researchers of the British Antarctic Survey report on recent measurements of the sea ice over the Weddell Sea off Antarctica . Bottom line: the sea ice was at a record low over the summers of 2016-9.
These measurements are based on satellite observations of the ice, weather stations reporting air temperatures, and ocean buoys reporting sea temperatures.
Obviously, sustained low ice is important, especially as the NYT headline put it, “The Iciest Waters Around Antarctica Are Less Icy” . Melting sea ice doesn’t directly raise sea level, but it does lower the albedo of the sea, possibly leading to warmer sea water, and follow on effects from that. And the warmer the sea, the less ice that will form, in a feedback loop.
(This ice shelf is also an important habitat for penguins and seals among others, so lack of ice is really hard on wildlife.)
However, the research indicates that these conditions, while unprecedented “in the satellite era”, are due to a combination of effects, not necessarily a sustained trend. This is made pretty clear from their graphs of the estimates for last 40 years, which bounce up and down quite a bit. The last three years are unusual, but it wouldn’t be surprising to see the ice extent bounce back.
However, with general warming and feedback effects, it is also possible that the sea ice will continue to melt each summer, which would be a significant indication of major climate change in Antarctica.
So, we’ll keep watching.
- Henry Fountain, The Iciest Waters Around Antarctica Are Less Icy, in New York times. 2020: New York. https://www.nytimes.com/2020/06/17/climate/antarctica-sea-ice-climate-change.html
- John Turner, Maria Vittoria Guarino, Jack Arnatt, Babula Jena, Gareth J. Marshall, Tony Phillips, C. C. Bajish, Kyle Clem, Zhaomin Wang, Tom Andersson, Eugene J. Murphy, and Rachel Cavanagh, Recent Decrease of Summer Sea Ice in the Weddell Sea, Antarctica. Geophysical Research Letters, 47 (11):e2020GL087127, 2020/06/16 2020. https://doi.org/10.1029/2020GL087127