Update on Arctic sea ice minimum volume

Reading previous post on the Arctic sea ice extent, you could ask yourself: what about the Arctic sea ice volume? Well, that is the exact same question that I asked myself when I was busy creating the minimum Arctic sea ice extent graph. It was a long time ago when I looked at the Arctic sea ice volume data. That was in 2016, at the time when predictions of an ice free Arctic, that until then were based on sea ice volume, suddenly switched to sea ice extent and I was a bit puzzled by that back then.

In 2012, Peter Wadhams predicted an ice-free Arctic by 2015 based on the “exponential” decreasing Arctic sea ice volume trend. He illustrated that by showing this graph from the PIOMAS project at the University of Washington:

PIOMAS Arctic minimum volume 2015 prediction

That graph was also the inspiration for the updated minimum Arctic sea ice extent graph in previous post. Let’s now do the same in this post and upgrade the minimum sea ice volume data and see what happened after 2012.

I will also use the PIOMAS Arctic sea ice volume data that was used to create the above graph. By extracting the lowest values of each year, I was able to recreate the dead-spiral graph:

Chart0017c: Arctic sea ice minimum volume 1979-2012 with cubic trendline

I tried many trend lines and it is the cubic trend line that has the best fit. The projected trend also collides with the x-axis around 2015, just as in the University of Washington graph. Going back to my extent graph in previuos post and trying the extent data with a cubic trend, this has an even better fit and extent would hit the x-axis around 2020 (see update of previous post).

It is clear why the switch from volume to extent was done in 2015. Imagine projecting an ice free Arctic in 2012 and after three nail-biting years it becomes clear that the Arctic did not become ice free at the end of the melting season. On the contrary, all three years between 2012 and 2015 showed a greater volume than 2012. The sea ice extent was also very low in 2012, but projection of an ice free Arctic on extent data reached somewhat further into the future (using the same method, it would be around 2020, compared to 2015 for the volume data). Which would explain the sudden switch from volume to extent data in 2015, it bought some years for the prediction of an ice-free Arctic.

That aside. With all the work on previous graph done, it becomes very easy to add the latest minimum volume data from 2012 until 2021:

Chart0017c: Arctic sea ice minimum volume 1979-2021 with cubic trendline

Which is pretty similar to the update of the minimum extent graph in previous post. Something definitely happened to the dead-spiraling trend, otherwise there wouldn’t be much, if any, Arctic sea ice by the end of the melting season in the last few years. Again, I don’t know whether the current trend will continue or whether sea ice volume will increase or start spiraling down again, but I haven’t seen the comparison presented like this before. Am I the only one who saw the 2012 projection and wondered how that deadspiraling trend would compare to the trend after 2015?

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July 12, 2022 at 04:21PM

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