Arctic sea ice extent meltdown

Arctic sea ice extent meltdown has come 77% of the way from Winter Maximum to a Blue Ocean Event per September 21st. The lowest extent year ever, 2016, for comparison, was at 73%.

Q: Where’s the data source for this plot?
A: Here: https://ads.nipr.ac.jp/vishop/#/extent
Q: How can anyone know if there is a Blue Ocean Event?
A: Easy. Use a computer. If you have less than 1 million km² sea ice extent in the Arctic, then you have a Blue Ocean Event.
Q: Why would I even do that?
A: Let’s say you want to know when the Arctic Ocean goes ice–free. Basing this on satellite measurements instead of gut feeling makes your conversations more interesting.

Due in large part to ongoing Collapse of Arctic Sea Ice our Frozen Earth is Going South.