To start, yes, I agree with all the rest of the comments. Of course if you look at the action needed to start within the 1.5 degree carbon budget, it's simply impossible. It's kind of like saying how much better humanity would be if there were no wars - a nice thought, but also not going to happen. I'm curious, though, and I admit I haven't read the report, but what is it about 1.5 degrees that the scientific communi…
1.5 degrees is commonly talked about because almost every country on earth pledged to "pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels" [0] in the Paris agreement. We won't hit that anymore, but it makes sense for scientists to compare the taken measures with the original goal. Every degree matters and aiming for 1.5 and missing by 0.5 degrees is better than aiming for a "realist…
In that case, I think still harping on the 1.5 degree number is a communications mistake. It is obviously impossible at this point (see the edit in my original comment), and so I think focusing it risks encouraging a "well, this is obviously too late, might as well enjoy our bread and circuses while they last" attitude. I think it would be much better if scientists said "Remember when we warned you about that 1.5 degree limit? Well, y'all f'd that up, so now a lot of these dire predictions are going to come true. Oh, and here is a whole host of even more dire predictions that will occur for every .1 degree you miss the limit, so you better try to limit carbon emissions as much as you can to prevent things from becoming more screwed than they are already guaranteed to be."
I just think that any messaging that talks about things eventually being "too late" is bad from a public motivation standpoint.