Wednesday, May 18, 2016

Arctic Sea Ice Just Set an All-Time Record Low(*)

*Tonight's Arctic sea ice extent: 4.06 standard deviations below the mean.

That's the lowest in the records, which start 11/1/1978.

I'm calculating with the daily JAXA data -- daily NSIDC data is still offline. The Arctic sea ice extent value for yesterday, May 17th, was 11.145 million square-kilometers. That's a full 5.2% below last year's value on this date, in a world where the average annual decrease since 1978 has been -0.4% per year.

This year stands out starkly compared to others in this century (click to enlarge):

It stands out even more if you measure the anomaly in standard deviations from the mean. I've taken the baseline as 1981-2010. Using the standard deviation of the anomalies over this period, 2016's anomaly for May 17th, -1.22 Mkm2, is -4.06 standard deviations below the mean (click to enlarge):

That result isn't independent of the chosen baseline, but this is a reasonable baseline and it's still a notable result.

Even the notable lows of Sept 2012 didn't reach 4 stdevs below the mean....

1 comment:

JoeT said...

Thanks for this post, David -- 4 sigma, it wouldn't have occurred to me. Two things I would add to this. If you look over at climate reanalyzer: we're going to see anomalously high temperatures in the Arctic for at least the next week: 3-4 C for the Arctic as a whole, 10C and higher in specific locations. There was a rather nice article at the ENSO blog describing how the current El Nino led to a breakdown in the stratospheric polar vortex which, at least in part, led to higher temps in the Arctic and the somewhat cool spring that the US has been experiencing in the Midwest and NE states.

Two other things off-topic. As we've discussed several times already, the Sherwood/Nishant 2015 paper in ERL shows evidence of the tropical troposphere warming faster than at the surface. It's probably not the last word on the subject, but it's no surprise that satellite measurements don't see it because the TLT measurements are looking too low and the TMT data is influenced by the stratosphere. The often made claim that the data doesn't agree with the model is simply too boring to read already.

Finally, if you hadn't seen this FYI from the AIP
I thought it was something that not many have picked up on. Aside from the inquisition conduction by Lamar Smith against NOAA, what caught my eye in particular is that Smith used the recent Fyfe paper -- --- to beat up on Karl et al by falsely claiming that this paper supports the concept that there has been no warming for the past 18 years. What is striking about the Fyfe paper is that they don't put error bars on the temperature trend! Grant Foster does a nice takedown of the paper here
It's astonishing that very reputable climate scientists like Mann, Santer, Hawkins, Meehl etc, would put their names on a paper that doesn't have error bars on the trend derived from the data.