This graph shows the same story even better:
...
Indeed there are similar versions of this chart floating around, some with smoothed data, some not, etc.
The main point of this chart is that, when the trendlines meet is when total summer melt = total Arctic sea ice from previous winter(s). In other words, a zero sea ice Arctic.
Chris Reynolds used a version of this chart to predict zero ice by the mid 2020's, but he was assuming a small, linear drop in maximum (April) Arctic sea ice volume after 2014. Unfortunately he posited a
"slow transition" (see the thread by the same name here on ASIF) to a sea ice free Arctic based on this small, linear drop in maximum (April) Arctic sea ice, itself based on a simple thermodynamic negative feedback (heat loss during Arctic winter getting higher and higher as the ice gets thinner and thinner, hence the ice thickening being faster and stronger after a summer with more melt).
2017 is showing that AGW and positive feedbacks resulted in a record, step drop in Arctic sea ice volume at the end of March / beginning of April (see the PIOMAS thread). In other words, positive feedbacks have largely overwhelmed the negative feedback described by Chris in the winter 2016/2017 and the two (quadratic) trendlines should meet sooner than the mid 2020's.
Another way of stating what is happening in 2017 is to say that we have just entered a new Arctic climate regime which will stabilize when we get a year-round, totally ice free Arctic ocean, and the transition from the current state should be quite fast.
No "slow transition", but rather, an abrupt one.Quoting from Tamino's blog:
"The loss of Arctic sea ice is so great, so rapid, so alarming and surprising, it’s powerful evidence of dramatic man-made climate change."(from
https://tamino.wordpress.com/2016/09/28/its-the-ice-stupid/ )