Arctic Update Mid–June

Thank God there are still simple matters in life where you don’t have to wonder or ponder about what actor did what to whom. And the abrupt disappearance of ice in the Arctic is just such a matter: No one did squat to stop it, and that’s why it’s going away.

Take the 5-year average for sea ice as an example: Does it display a downward trend? And is that trend rather steep & aggressive? The correct answer to both of these questions is Yes, indeed. On the 21st of May, the average went below 13.7 k km³ for the first time on record (1979-2020), meaning the average of every single day for the past 5 years is lower than the average of any other 5-yr period on record.

Another way of saying that is where we are now is the lowest we’ve ever been. Of course in terms of a 5-yr average for sea ice volume. That gives us the long–term perspective, but of course there are other ways of looking at the Arctic. In fact there are plenty of ways.

In the short–term, there’s the annual or one–year average volume, where we remember that 2019 was the 2nd lowest of all. The lowest year, first proclaimed by this blog’s predecessor, was of course 2017. That year is still the only one on record to average below 13 k km³.

Many people and even some ‘experts’ still believe 2012 was the lowest year, but it was beaten by 2017, and now even 2019 is lower:

Annual sea ice volume graph from PIOMAS at Uni–Washington.

One of the many reasons people still believe 2012 is lowest, is that unlike temperature, which is always referred to in annual averages, sea ice tends to be measured by one day only, usually a September day. In a way, that would be like measuring the entire year’s planetary temperature by One day that you choose and for One spot that you also choose, you know, like that One day in June back in 5th grade when it snowed in Southern Norway. Is it representative for the entire planet, and the entire year? Of course not, it’s the kind of trick a climate–denier would play.

But granted, it IS also interesting to look for the absolute minimum amount of ice at the far end of the summer melt season. Could we have an ice–free Arctic this year, a so–called Blue Ocean Event? Well, not according to this plot:

Here it’s only a 3% chance that the September minimum this year will be ice–free, defined as less than a million km² sea ice area in the CAB, or Central Arctic Basin. The app behind the plot calculates the melt needed for every day till melt ends, and then compares the melt actually observed for that day, to the ‘needed’ melt. If no days can show enough ice melt, the % will be 0, and if half the days meet the demands, chance will be 50%. We can see 2020 being last in line of the past 5 years, meaning at this stage of the melt, we’re not very impressed by 2020’s performance. (Although it can be argued that the inner, most freezing part of the floating ice doesn’t start melting regularly before Summer Solstice and perhaps July.) Of course, a Blue Ocean Event never happened before in documented history, so a lot of eyes are fixed on this statistic and this eventuality only.

Some people like to look at the ice ‘directly’, or through satellite censors, in order to judge the progress by ice coverage in particular places, or degree of melt pond formation. Here we got tons of melt ponds on the sea ice, in a picture of the Nares Strait (right) and the Nansen Fjord, the planet’s longest fjord (left). Bottom middle you can see the famous ‘arc’, or the arc-shaped ice edge within the Nares Strait. The strait has been known to open or stay shut at widely varying times and periods of the year, and it does transport a fair amount of ice out of the Arctic, but the truly big export channel is of course the Fram Strait to the East of Greenland, named after polar explorer Nansen’s vessel and expedition. A fun fact is, if the Nares were a freshwater river, and not an ocean water strait or stream, its flow of water would be 10 times that of the Amazon river in terms of volume, which is interesting because the Nares is actually one–directional and thus acts like a river.

Uni–Hamburg has the most high–resolution sea ice concentration product on the web, and when you zoom it or view it like the above, you get a very quick overview of where we’re at. This is from June 15th.

Finally, I’ve included the Japanese interpretation of the daily sea ice volume for June 15. They say it’ll be a melting season out of the ordinary, so let’s follow closely what happens, when it happens!