The only meddling with nature that went horribly is repeatedly introducing invasive species, then seeing the result after a short time.

And the part that isn't discussed at all, of course, is that that happens all the time in nature.

Of course the solution to climate change is humanity taking control of the climate. But the problem with that is equally simple: warming is inconvenient, but generally helps everyone. Cooling, on the other hand, ... or even merely stopping the warming.

For example, if you started cooling the Ganges valley, it loses about 92% of it's water supply 1 or 2 years after the temperature stops rising (because it's glacial meltwater). That's a billion people, including the entire country of Bangladesh that will be moving. And when it comes to a moving date, to these people, tomorrow (as in never) will always look better than any possible agreement.