Warm Arctic Winter sees sea ice max out at a record low

22 03 2015

Whilst the entire planet has warmed over the last century, the Arctic has seen the greatest rises in temperatures.  One of the most obvious symptoms of that change has been the changing patterns of sea ice movements covering the Arctic Ocean each winter. Although the extent of its summer time melt is variable from year to year, there has been an obvious sharp downward trend in the amount of Summer ice left each September, but, as the Arctic moves into 24 hour darkness through Winter, most of the ocean freezes over again and everyone concentrates on how low the Summer maximum coverage goes.

This year though, unusual (but predicted) winter warmth at the edges of the sea ice has led to a most unusual refreeze, and a record low for the maximal ice extent has occurred….  This year’s maximum extent of ice coverage of 14.54 million square kilometres, was more than a million square kilometres below the long-term average.  Usually, the peak of the refreeze happens in March, but this year, ice coverage started dropping in late February.  Then it stabilised for two weeks. And that was that…..  This change in behaviour took the cover area outside of two standard deviations of the 1980-2010 average ice extent.

The NSIDC (National Snow and Ice Data Center) which monitors these things, tells us that there may be further freezing yet to occur, but unless that freeze is extreme, ice coverage is  not likely to revert to where they were in February.

What caused this unusual drop?  Temperatures above most of the Arctic were, surprise surprise, unusually warm.  In the Barents Sea, many locations temperatures reached levels that were a full 10°C above average.  Just think about what it would be like if the temperature where you live reached such heights?  Oh hang on…..  it happened here just last week, and Western Queensland has been 10°C above average for a couple of weeks now…. (last Thursday here in Cooran, we had 12°C above normal for this time of year, only for the one day fortunately… and March temperature records in Queensland tumbled all over the place)

But back to the Arctic….  Ice extent was lower there, in the Bering Sea, and in Russia’s Sea of Okhotsk.

What does this mean for this summer’s melt?  Who knows…  All bets are off now as far as I’m concerned…  If you compare the graph above to one of recent summer melts, you’ll see that in 2012, the summer that saw the greatest loss of ice, actually had a winter maximum that was late in the year and above average—the exact opposite of this winter.  So if this Arctic heatwave continues, will we see the first ice free Summer sooner than anyone has predicted?




2 responses

22 03 2015

I’m sure you know about the Arctic jet stream and its meanderings, which brought an extra cold winter to eastern US, and an extra dry winter to western US. But these events were mostly weather and only slightly the slow steady progression of climate change. “meanderings” is the key word here.

What you need to do to get a handle on the variability is to plot, not the WORST day sea-ice-wise, (because that is selecting the worst day’s data point, not the average of the season’s data point) but the sea ice on a certain day every year – the equinox would seem to be the obvious one to consider. Then look at how long a period of time can occur between instances of a record minimum sea-ice and the time it takes for a new record to be made.

It turns out sometimes new records lows on the equinox are made in consecutive years, and sometimes records stand for ten years or more, and usually it is somewhere in between. So if 2015 equinoces turn out to be record lows, then it doesn’t mean 2016 will also be a record low too.

As for heat waves in western Queensland, we have to wait for the weather reports to tell us that records were broken – we can’t tell ourselves unless we have kept temperature data for many decades. You must have heard things like “and Coober Pedy had its hotest day for 74 years!”, which means it wasn’t that unusual at all. I had minimum indoor temperatures of 31°C for a couple of days over summer, and then I realised I had shut some windows earlier and forgotten to open them. My maximum indoor temperature over summer was 36°C, which is not unusual for a few days a years, so no records broken here, quite average in fact.

22 03 2015

Unlike you though, I believe in tipping points, and that we MAY have reached one……. like all tipping points, we won’t know for sure until we see them in the rear view mirror. IF we are at a tipping point now, then weather events could be climate events. Everything’s changing very fast up there, which is why I worry about tipping points……. because if we have reached one before collapse bites, then it’s all over rover.

Interesting how your house operates so differently to mine too! When we had 37.4C under the insulated southern verandah the other day, the inside temp never went over 28….. then I stupidly opened all the windows and doors to ventilate the house around 5:30PM, but that was too early, and in no time the inside temp rose to 30! Of course that meant the house had a devil of atime cooling down overnight, not going below 25 at 5AM, and even though the following day was cooler at ‘only’ 34, the internal temperature almost reached 30…. won’t be doing that again without checking it’s actually cooler outside than inside….

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