(This entire discussion might need it's own thread called "effect of cloud and water vapor in arctic and austral winter")
Let me construct a cartoon picture. I ignore many things, but bear with me.
To first approximation, earth is in energy balance (to +/- 1 watt/sq. meter )
Shortwave solar input is on the order of 1kilowatt/square meter
Most of the heat goes in around the equator. Most of it is lost from the currently dark pole, north pole in northern winter, south pole in southern.
so a kilowatt/sq. m. or so got to go out from the dark pole.
The oceans are like a big capacitor in the middle of the input heat and output heat.
Now put a cloud cap on one dark pole every winter, the heat cant get out in winter from that pole. Several things happen.
1) Winters get hugely hotter in that hemisphere.
2) Heinrich events as grounded ice melts.
3) Ocean circulation reorganizes to export much more heat through unclouded pole.
We may be seeing 1) but not yet 2) and 3)
Timescale for 3) is, of course, the timescale of the bipolar seesaw, a few millennia, so we wouldn't expect that right away.
Of course, none of this says that water vapor/clouds are actually increasing in arctic winter. But it is something i wish someone were watching.
(This all began with a discussion with a paleontologist and a zoologist about to how one could have alligators in the arctic. Cloudy, rainy winters seemed to be their view.)
sidd