Apologies all, that I haven't recently had the time to contribute, or even follow recent discussions...
My tuppenceworth (with apologies to those who have heard this stuck record a couple of years previously on the ASIB...)
The much-touted annual minimum is insignificant. It is followed by a period of 6 months of 0% albedo feedback.
The autumn/fall is the most critical period. Can the cold atmosphere sufficiently cool the liquid seawater so that it EITHER floats, as ice, and then cools further, OR sinks, as colder denser still liquid seawater? A solid ice surface can quickly drop to -30C, whereas liquid seawater is around -1.8C or above, by definition.
If the vagaries of ocean currents deliver hotter seawater to the Arctic surface in sufficient quantities that the atmosphere cannot quickly grab it, and retain it at surface by freezing it, it will sink, and be replenished by further supplies of anthropogenically warmed seawater. A conveyor belt of heat; which will warm the local atmosphere still further.
I'd be interested to know if anybody here can calculate whether any area of the earth has ever, since records began, been more anomalously warm than the Arctic over the last 3 months of 2016? Sahara at 70C? Europe in Summer at 50C?
My opinion is that the annual solar cycle of 2016, or any other year, which raise the ambient Arctic SAT from -30C in midwinter to 0C in midsummer pale into insignificance beside the accumulated energy absorbed by the planet over the previous 4 billennia, (with a huge increase in the energy retained due to CO2 forcing over the last few decades,) which has raised the global average temp from around -265C (absolute zero + geothermal) to around +12C. That heat is stored primarily in the oceans. The new modern anthropogenic component of it will have greatest effect if, due to a related disruption in the jetstream, Atlantic heat is hurried North during the autumn/fall. That could, in theory, produce a situation in which large areas of the Arctic surface do not refreeze as usual, but remain 30C above normal. In theory, and also, this year, in practice...