Saturday 22 October 2016

Arctic Sea Ice extent - 10/21/2016

Arctic Sea Ice Collapse 18—20 October: Annual Average Extent

21 October, 2016
2016 Arctic sea ice making a dramatic October plunge into record low territory for annual average extent:

in this season of seasons i see
collapse itself collapsing and the
future of future spinning like moths
in the lamp on a floor of dead moths

We are now officially lower than 2012, both for daily sea ice extent and annual average, and you can see the 2012 graph never goes as low as 2016 was for October 20th. The only remaining record low before Wednesday for Annual Average Extent was the May 2013 all time low of 9.916 million km² (set by the 365 days leading up to and including May 15th 2013), and now no single previous day has been lower. Plot shows annual average* extent, not daily extent.

Graph highlights a likely future of sustained lowest ever annual sea ice extent.

Eyeballing the graph, the blue dotted line and confidence interval suggest we'll be below 9.8 million km² by November—December, so dramatically lower than both 2012 in autumn and 2013 during spring. We've truly entered the dreaded uncharted waters, where — literally — anything can happen. Including annual and ever longer 
Blue Ocean events. We're into the great wide open.

To visually present the new all–time record low for annual extent, the above graph has been laterally expanded all the way back to January 1st. Then you can clearly see the May 15th previous record on the pink 2013 graph:

Annual Average Extent (AAE): From the last update at about 9.92 million km² on 17th October, we've lost about 11200 km² from the AAE in just 3 days, which was within the expected timespan of October 20—22.

In detail, daily extent went from 5,756,548 km² on 17th October to 6,153,229 km² on 20th October, compared to 7,043,581 and 7,363,764 the year before, giving a relative 
gain of 76,498 km². The average decline in AAE over these 3 days has been 3555 km²/day, which means we've been on average 1,298,000 km² lower than last year in daily extent.

The next 10,000 km² line is 9.9 and expected on 
October 23rd.

JAXA Annual Average Extent for 2015 as a whole was 4th lowest at 
10.11 million km², and since Mid–July we've been lowest ever at 9.91–9.98 million km². For the first time in 4 years we may end up lowest ever on December 31st.

We're now already into uncharted waters. Some very interesting times ahead, with the best chances yet for a
Blue Ocean event during the next ten months.

The next major milestone of the Arctic sea ice collapse is 9 million km² AAE, and expected in 
*) Don't get it? Just about once every month there is a new person actively voicing their concern that this is all wrong. I've totally messed up and I don't even know ice melts in summer and ocean freezes over in autumn and winter. I'm not a teacher, so I can only explain the concept of an annual average scientifically. I don't know what motivates the person in question to actually go and read the mathematical explanation. I usually don't know that person at all. I've been publishing annual average graphs since 2014, and I can assure you they are not wrong. Mostly, the monthly concerned person didn't get the 'annual average' part. Or they thought it wasn't essential to the understanding of the graph. It is.

PS: For the 
7–year outlook, have a look at this post.

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