Post #2790698

2026-04-12 16:29 UTC

@Brad_Rosenheim@climatejustice.social I think that theory has been the basis of several high profile papers. If there was any truth in it then sea ice extent west of the Peninsula and in the southern Bellingshausen Sea should have been increasing over the past few decades. In reality there has been a steady decline in sea-ice extent in these areas through the period of the satellite record, even while extent was steady or slightly increasing in other sectors up to 10 years ago.

Replies (2)

@Brad_Rosenheim@climatejustice.social 2026-04-12 18:07

@PoLaRobs@fediscience.org I think I've chatted with @carlosmoffat@fediscience.org about it before, and he does the kind of modeling that would be important in assessing if this was happening.

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@PoLaRobs@fediscience.org 2026-04-12 18:12

@Brad_Rosenheim@climatejustice.social A further thought on this. The average surface water salinity in the Southern Ocean is about 34.5 ppt, which depresses the freezing point by nearly 2°C. If a large flux of melt decreases the salinity by 1 or 2 ppt, as happens around the sea ice edge when it is retreating in Spring, this raises the freezing point by around 0.1°C. I think other factors, including atmospheric and ocean temperatures and winds, are likely to be much more important in controlling sea ice extent. Furthermore, any melt added to the surface water in summer will be mixed into the upper ~200 m of the ocean by autumn storms before it can have much effect on new sea ice growth.

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