Everything in the more general direction of environmental engineering has failed IMHO. For instance speaking of efforts to limit animal populations in Australia that led to explosions of other animal populations. Or trying to make rivers straight. Also considering the concept of sponge cities and that Wuhan is one of those isn't very reassuring.

But generally I'd agree if everything else possible was done (like a 10x reduction of fossil fuel) but we've not even started. In fact CO2 emissions increased 6% in 2021.