I think Prof. Waldham is rather out on a limb here. I’ve read of some simulations in which the Arctic was posited ice free this year. Going forward from there, those simulations found that the Arctic regrew a sea ice cap of some size. It’s just not warm enough there, yet, to allow for open seas on September 1 at the pole itself and in the region between there and Greenland.

More likely, we will see a continued downward trend in Arctic sea ice, with the NW passage open to traffic escorted by icebreakers during August and part of September. The general breakup of the polar cap will probably come some 20 to 50 years later.

The trouble with end-is-near predictions is that when they don’t pan out, people dismiss all the science, not just the speculative part.

As to geoengineering, it’s an interesting idea and it might be necessary at some point. But to embark upon it while the climate is still tolerable, and in the absence of any agreement on CO2 reduction, is to sow the wind.

What will become of us if we slip into an agreeable routine of dumping first a little, then more, SO2 into the stratosphere, all the while merrily burning as much coal as we can get at?

Let there be a lapse in our diligent attention to the geoengineering task, and world temperatures would rocket up. No time for evolution to keep in step with the changes. No time, even, for our own industry. Seas would rise year by year, not decade by decade. Crops that had been OK one year would fail 5 years later. All of this at a time when we were least able to cope, because of the same civilizational stutter that caused us to drop the ball on the geonengineering in the first place.

The money that might now be spent on geoengineering could better be spent on R&D into wind and solar. These technologies are improving steadily, even rapidly, but with yet more R&D they could make faster progress. Major spending now on R&D will minimize the cost, and maximize the impact and scale of what we can achieve in the way of mass conversion of our economy to wind, solar, nuclear, and other non-fossil fuel energy.

Doing it that way gives the added bonus that we needn’t make the sky permanently milky and hazy. Clear blue skies won’t be a myth and an inexplicable metaphor to our descendants, but a birthright we vouchsafed them.