Very interesting race indeed. I will be away from my computer for some days but have made some calculations analyzing the "inner basin" volume gap. Pray excuse rounding errors and no chart. Note: all my "averages" include only 2010, 2011, 2012 and 2016. Numbers are in km3.

First, 2017 had a slightly above-average inner volume loss, 2460, reaching 10,656 on day 181, compared to 2012 at 11,480 and 2011 at 11,333.

Comparing by region vs 2012:

Sea - 2017 lead day 166 - 2017 lead day 181

Beauf -73 -16

Chukc 496 477

ESS 293 422

Laptv -310 -152

CAB 598 210 big change

CAA -29 -149

Total inner ~970 ~820

Looking at losses to day 196 (mid-July) with a clustered range of 2539-2691, and assuming low-typical 2550, extrapolated 2017 will get to inner basin volume of ~8,100 and lead of ~680. Race not over. (But of course August was the real freak).

Looking at regional distribution and the comparison maps, it's mostly a tale of Pacific side vs. Atlantic side. As the Atlantic side is much more vulnerable, I would say it's one more advantage to 2017.

On the other hand, 2012 had ice left only in CAB and CAA at minimum (besides Greenland sea) and the lead in these two regions has almost vanished.

Interesting indeed.