Sunday, April 10, 2016

Arctic Sea Ice Extent Still Sucks This Year. Why You Should Care

Much less ice formed in the Arctic han normal this
winter, continuing a downward trend in the amount
of ice way  up north  
The high Arctic gave us a couple blasts of mid-winter style frigid air this April, but even so, things are continuing to be way, way too warm up there.

I guess the cold blasts were a big "Frig You!" from the North Pole, which despite its ample supply of frigid air, is still having big trouble generating its yearly supply of ice.

It's always cold up there, of course, but this winter was freakishly warm in areas above the Arctic Circle, at least by their standards.

It was so warm up there that sea ice extent in the Arctic stayed at record low levels almost the entire winter.

And, back on March 24, it looked like the ice up there in the Arctic reached its peak for the winter, and it was the lowest maximum extent on record.

The ice up in the Arctic covered about 5.6 million square miles, which sounds like a lot.

And it is. Just not as much as it always gets in late March. At least until now.

In the Arctic, winter, averaged over the whole large region was something like four degrees Celcius warmer than average. That's a huge departure from normal, and you can see why the ice formation was slower than normal up there.

The lack of ice this year is about the same as last year at this time. Just maybe a smidge less this year than last.

The low level of ice up in the Arctic could set the stage for the smallest amount of ice covering the Arctic on record later this year.

Usually, the ice extent reaches its annual minimum in September.

There's no guarantee this summer's Arctic ice extent will be the lowest in modern history. Weather patterns could slow the  warm season melt. If that's the case, ice extent will probably come in below normal, but not the tiniest ever.

Even if the Arctic doesn't set a record low for the amount of ice this year, you have to look at the long term trend for the ice,  which is down, down down.

Oh sure, there are a few brief hiccups upward in the amount of ice, but looking over decades, there's a less ice than there was, say, 40 years ago.

Lower and lower amounts of Arctic sea ice are bad, because the white or white-ish ice reflect sunlight and warmth back to space.

If you remove a lot of ice, there's darker open ocean water, which absorbs sunlight, rather than reflects it.

That's called a positive feedback loop: The ice melts, which enables open water to absorb more heat, which makes even more ice melt, exposing more ocean, etc., etc.

Which means there's no sign that the overall trend for declining Arctic ice is going to end soon.

As noted in previous posts, this loss of ice can also screw up weather patterns, making the jet stream meander northward and southward in dips and ridges much more than it used to.

There's no way to know for sure but there's a chance the April chill we just got was partly due to the a jet stream that is wavier than it used to be because of this relative lack of northern ice. This is just speculation, of course, but it makes sense, given what the scientists are telling us.

If you want more and bigger and more dangerous weather extremes with less predictability, Arctic ice loss is your friend.

The ice loss has a lot of acute, more local effects in the Arctic as well. Various animal species are threatened. As Scientific American notes, there are declines in polar bear populations and signs of stress among walruses forced out of their feeding grounds in shallow water as ice retreats to distant, deeper water.

Since there's less ice, coastal communities way up there are vulnerable to erosion. Open water obviously sloshes around with waves, which can blast away formerly frozen shorelines in places like northern Alaska.

The loss of ice way up north is even changing the way the Earth tilts on its axis. The change is subtle, very small and harmless, but it's still measurable, says The Guardian

The North Pole for much of the 20th century was tilting slowly toward Canada.

Now, it's starting to tilt a little more toward England instead. That might be because enough ice is melting off of Greenland that it's making its weight on the Earth less, changing the direction of the tilt.

By the way, slightly south of the North Pole,  March was totally warm in Alaska. The first recorded temperature of 70 in March happened this year. March was a whopping 8.4 degrees warmer than normal in Fairbanks, Alaska. The warmth has extend into April, with the first week of the month running 12 degrees warmer than normal.

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