Back when I was an academic, I used to attend my share of ecology conferences. I would hope that my presentation, for there was no point in going unless you presented a version of your latest research, was early in the piece so that I would have some extra people to talk to. Most of my former colleagues were innately curious, and they would always ask questions of the presenters in the tea breaks.
Much of this was about posturing, being seen and to see, sidling up to the senior gurus to let them know you existed. Only occasionally did any of it tackle the real issues. Sure there were criticisms of your experimental design or the incorrect use of multivariate ANOVA, but rarely anything about why you were spending so much time and effort on the breeding phenology of woodlice.
I wish somebody had asked because in my head was a bespoke answer.
Knowledge matters, I would have said, no matter how esoteric it seems. It matters because it can lead to understanding and that is what we need in this world.
How naive I was.
If I could go back and was brave enough, I could present a version of this insight instead.
Good, but I don't think it went far enough. You can't design an economic system using half the energy and still expect it to be sustainable. It has to use only energy that is sustainable (i.e. does not require use of materials that have to be mined and refined). Would such a world be recognisable as a modern world?
So, you're right, complete change is needed but the kind of change needed for zero environmental impact (any negative impact will eventually also require change) doesn't result in a modern society. It probably doesn't result in what can be thought of as a society at all. The rest of life has a hunter-gatherer lifestyle. Humans will eventually have to revert to that, and act like all other species. That may not be desirable to anyone (other than those who are still living that way) but reality doesn't care what any life-form wants.