Let's do a little math Frank. The most recent value for the September trend line is about 5,200 cubic kilometers. The line is descending at 3,200 cubic kilometers per decade. Hmm... tricky here. 5,200/3,200 = 1.625. 1.625 decades is 16.25 years. What I shall presume to be the 2 sigma lines have current values of 8,000 and 2,300. Those give us a range of 25 years down to 7 years, 2 months and a week ( ;-) ) Those would make up my prediction. Do you have some data that counters those numbers?
You might note that this is based in NO part on the recent Arctic heat wave.