Is the Arctic sea ice ‘spiral of death’ dead?

This year, as every year, there has been much excitement in the media about ‘catastrophic’ melting of Arctic sea-ice, run-away melting, tipping points, death spirals and “ice-free” summers.

There has been the usual guessing game about when exactly the minimum will / has occurred and what the ice area or extent will be on that day. arctic-spiral

Claims of ‘ice-free’ conditions at some time in the summer have been bandied about for years in various forms but as the reality sinks in that it’s not as bad as some had claimed, the dates when this is expected happen have often been pushed out beyond the life expectancy of those making the claims.

The meaning of “ice-free” has also been the subject of some serious goal-post relocation efforts, we are now told that ‘ice-free’ does not actually mean free of ice, it means there will be less than one million square km of ice left.

This special branch of mathematics is apparently based on the axiom that zero = 10 6

The problem with this obsessive focusing on one single data point out of 365, is that there is a lot of short term, weather driven variability that can affect the exact timing and size of the minimum in ice coverage. Since the main interest ( outside maritime navigational requirements ) is the hope to find some indications of long term changes in climate, this is not a very instructive way to use the detailed data available.

There have been three notably low summer minima in recent years: 2007, 2012 and 2016. The 2012 event was the lowest in the satellite record going back to 1979. The other two years tie for second place, meaning the current minimum is indistinguishable from the one which occurred nine years previously and the lowest one lies between the two. This incompatible with claims of run-away melting. This was a reasonable hypothesis and cause for concern in 2007 when the relatively short record could be characterised as an increasing rate of change but this interpretation is not compatible with what has happened since.

In the golden days of “run-away” melting, leading up to the ‘catastrophic’ 2007 Arctic sea-ice minimum, this was often presented as the ‘canary in the coal-mine’ for global warming and climate change. It is still referred to as such.

The aim here is to try to separate the changes in the annual cycle from the weather-driven and other short-term variability and to see if we can learn something about the life expectancy of our canary.

Read rest at judithcurry.com

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