Natural variability is not always your friend

Given that we now have now officially got an extraordinarily low Arctic ice extent (with a couple of more week's melt to come), the climate change "skeptics" are casting around for reasons as to why it doesn't mean all that much.

One of the more credible attempts at this appears to come from Judith Curry, who points us to a recent paper arguing that the enhanced warming in the Arctic from 1965 to 2000 was mainly due to a natural variability:

There seems to be a large multidecadal variability in the complex ocean–atmosphere system that can superimpose itself atop the global warming signal. It seems to be identifiable with a few large-scale patterns in the temperature fields; when phases of the pressure modes match up one with another they can enhance the rate of warming, especially on the large, wintertime continents. It is not yet known whether cooling periods can happen as well in this scheme. Nor do we know exactly the origin of the multidecadal long-term variability that has been identified. It could be related to anthropogenic causes, or it could just be part of the natural system’s internal variability.

But - as the summary notes before this conclusion:

What causes the two primary decadal empirical pressure patterns to ramp up their amplitudes and line up their phases in such a way as to encourage lots of warm air polewards onto the big continents during the study period and not at other times? Wallace et al. do not address this issue but list several contenders.

One possibility is that the anthropogenic factors are actually inducing this change in circulation, perhaps even through stratospheric connections as mentioned earlier. They seem to lean toward unforced natural variability at the decadal scales.

So:   even if you accept that the radiative forcing alone is not doing this (and I would presume that the fact that the IPCC did not predict an Arctic ice melt this fast indicates this may be right)  it remains quite possible that anthropogenic changes to circulation patterns are altering what appears to be natural variability to make it worse.

Besides which, even if there are no anthropogenic reasons affecting the circulation change, doesn't the whole exercise mean that even modest AGW is a problem when it gets a multi-decade boost from natural variability?

I mean, you see this failed excuse making re solar influences too:  sure, a quieter sun could make parts of the Northern Hemisphere cooler for a couple of decades, and that could be partially offset by AGW, but none of that helps when the sun goes back to normal.   What could be a mere bit of breathing space for just one area of the world would be no reason to not be working to dramatically reduce CO2 for when a short term cooling effect wears off.

Also - the particular problem with loss of Arctic sea ice - even if it is largely happening at the moment due to natural variability - is the feedback potential that it gives to AGW.   This might be a particularly unlucky coincidence that gives the AGW effects on the polar region a boost up to a level that it's not going to drop back from anytime soon. 

The "do-nothing" climate skeptics are interested in the short term only.  They do not take seriously the long term interests of the residents of the planet.

UPDATE:   In any case, here's a 2012 paper which appears to contradict the claim that natural variability has had much role to play in the recent Arctic ice loss.

Given the lack of evidence of substantial polar ice loss in other warm Earth periods, it seems to me to not make much sense that natural variability (uninfluenced by humans) is the substantial cause.