One issue I see with climate change is nuts and bolts, e.g., how do enough fast enough to make much difference.
We could implement a shift to nuclear power in 15 years or so for electricity (globally) but that won't happen. The rate at which more wind and solar can contribute from a very low base is simply not fast enough even if we through money at it.
If we went to zero carbon today, globally, we'd still have significant climate change, according to the various models. If every country met the Paris targets, the reduction in global temperatures would be rather small, again using the models.
I see politicians signing agreements because that's what they do, but real tangible progress to reducing carbon to me looks like something that won't happen fast enough to "stop" these trends. The one thing that might intercept and make a difference would be if ITER works and we can somehow developed practicable fusion reactors in a decade, but that also looks unlikely.
