Arctic Sea Ice

Arctic sea ice isn’t often out the news these days. Whether it’s used by climate scientists as a warning of things to come or by ‘sceptics’ as proof that things aren’t as bad as claimed, it seems the world is very interested on what’s going on up there.

It can be hard to know what to make of all this. One way to visual what’s going on is with Andy Lee Robinson’s 'Arctic Death Spiral'. (Note: many of the graphics this week are from tweets, to ensure their creators are properly credited. This doesn't mean they are poor science though; you can see the source of the data in each of the images. Have a look at those links if you want to find out more!)

#Arctic Death Spiral - October 2016 average vol: 5,539 km³ - 2nd record lowest (last year 7,052 km³, 2012: 5,036 km³) pic.twitter.com/zXmqkYy8dV

— Andy Lee Robinson (@ahaveland) November 14, 2016

Figure 1: The average area covered by sea ice in the Arctic each month since 1979 until October this year.

Each month has its own spiral because the amount of ice in the arctic changes dramatically over the year. As you can see from this graphic, the ice generally peaks around April and is lowest in September, and has dramatically decreased over the last few decades. After September, temperatures drop again and ice begins to form again. Worryingly however, this November has been anomalously warm; up to 20˚C warmer than average for this time of year. This has resulted in a record breaking lack of ice.

Okay, maybe time to let the #Arctic know what season it is -> another drop in #seaice extent from the last 24-hours (3rd day in a row, JAXA) pic.twitter.com/2Fl1pQUsD4

— Zack Labe (@ZLabe) November 20, 2016 

Figure 2: Arctic sea ice extent this month is lower than ever observed at this time of year.

In fact, as of Wednesday, over half the days this year have broken the record for the lowest extent of sea ice for that time of year.

2016 has now broken daily record min Arctic #seaice extent on exactly 50% of days so far this year. Crazy year in the Arctic! pic.twitter.com/crW9rdc3pV

— Zack Labe (@ZLabe) November 23, 2016

Figure 3: This year's Arctic sea ice cover anomaly relative to the previous record minimum for that date.

So what about all those articles asserting that the situation isn’t all that bad? Many are based around overly pessimistic predictions made during the record minimum of 2012 (see figure 4). The absolute minimum has not been this low since, with this year’s September minimum the same as that seen in 2009 (making it the joint second lowest coverage on record). However, although the terrifying event of 2012 is yet to be repeated, as figure 1 shows there is still a very significant decreasing trend. This trend is still outside the worst case scenarios predicted by early models (shown in figure 4). All in all, not all that reassuring, despite what the Daily Mail wants you to think.

Figure 4: Image from Skeptical Science during the record 2012 minimum compared to model projections.

The recent Arctic Resilience Report doesn’t provide much comfort either. It highlights the vulnerability of the Arctic to climate change, and lists 19 tipping points we are approaching there. This video from The Guardian summarises some of the most important (and terrifying) points from the report.

In summary, despite what can be taken away from cherry-picking data or very short term variability, we are seeing a significant and rapid loss of Arctic sea ice. This has the potential to have dramatic knock on consequences on the rest of the world. And if you’re still not convinced of the seriousness of this issue, just remember: no Arctic sea ice= no polar bears. Time to act.