I can understand a no answer from people who think climate change is no big deal, but it's kind of weird that people who think climate change will kill hundreds of millions -- possibly everyone -- say no on the grounds that it has risks.

Possible unintended side effects is better than "everyone dies".

Ten years ago, I was saying we should experiment with it on a small scale so that if it does become necessary, we're not shooting blind, but even then the doomers were opposed because of "risks". You know what else has risks? Unmitigated climate change!