I won't explain the back story, assuming that you have heard more than enough of the smarmy parts.

I understand the strategic political motivation to make all potential technological fixes to global warming seem like wacky, hare-brained, mad-scientist schemes to block the sun, but the more I think that through, the less it looks like responsible politics.

Just suppose that some form of climate engineering could (1) do as much or more to slow or halt warming than could regulatory approaches (2) at a much lower cost while (3) posing no special problem of international coordination. Perhaps Avent has already made the case that some technology (or combination of technologies) meeting this description is less likely to emerge in the coming decades than an effective scheme of international carbon emission controls. If he has, I’ve missed it. However, if the success of a primarily technological approach is no less probable to than the success of a primarily global political-regulatory approach, it would be egregiously irresponsible to discourage public support of efforts to discover such technology. If the probabilities turn out to favor engineering over politics, then emissions cuts, not engineering, should be considered last ditch.

There is zero chance that political-regulatory approaches will accomplish anything at all so far as climate change is concerned. Zero. The numbers don't add up even if the politics did, and they don't. The sole objective of those seeking political-regulatory climate power is power, and that easily explains why they will try to kill anyone who gets in their way.

Those who are sincerely concerned about climate issues would do well to study geoengineering proposals, but IMV the only ones that are worth a second look are those that seek to clear the air of excess carbon and use it productively.