The freezing season is very strong of late. After falling to lowest ever 2018 is now in 11th place, exceeding every year since 2006 in ice extent except 2008 and 2014. Can’t be sure what’s driving this since temps in arctic are not below average.
Quick from the hip theory - less imported humidity from lower latitudes, thus less to impede outbound longwave radiation, *and* lower humidity would permit greater evaporation, which is a very local energy transfer directly from the water surface that would drop sea surface temperatures even with "warmer" atmosphere.
Here is the thing though - relating to discussion on the area/extent thread - that exchange halts the moment the ice forms, and we change the primary transfer mechanism from primarily convective to primarily conductive. The "R" value of ice is surprisingly high, and permits snow accumulation, which makes prospects worse for heat loss.
Collapse repeat something else I've said... I think we are on the cusp of major deep system changes. As we reach and start breaking the system symmetry, its overallbehavior will become more volatile, especially considering the huge increases in total energy available (see: pentajoule-scale increases in total oceanic enthalpy).
In short, the rapid ice return is not reassuring. I may we rethink that if it happens 5 years running, but I don't think ill get that chance.
