Have a look at the chart you just posted, and tell me if 1.5C GWI by 2026 (out the top by the end of the x-axis) is consistent with current global temperature trends:

GWI has gone from 0.5C to 1.0C over the last 30 years. To project a similar rise to 1.5C in the next 9 years is a big call, and although the authors give a mechanism (IPO swing) they're also projecting that rise in 14 years without that mechanism, and the data don't seem to support a 0.5C trendline rise in temperature in such a short time. That's around twice the record decadal rise yet recorded for any decade. Sure, it's possible, but it's not a rate of warming that most climate scientists would subscribe to projecting over then next 9 years, but rather a figure right at the top of most projected ranges, or even a bit beyond the top.
Oh well, 9 years isn't that long to wait to see if you and Henley are right.
My personal view is that the Paris targets were set at 1.5C by 2100 exactly because that's unachievable, thus providing a political impetus for action when they're inevitably breached in another few decades. Outlier years like ENSO peaks going over 1.5C over pre-industrial even sooner will also (hopefully) concentrate a few relevant minds. We'll see, I guess.