There is a very simple way to make people pay for CO2 they produce by e.g. burning things: add a tax on it, so that the price increases. Tax oil-based fuels, firewood, coal. This will send the signal down every industry, adjusting price of goods accordingly. Use the money for the anti-warming geoengineering.
How popular might it be? Like, kill the whole coal industry around the world; who would mind? Make fuel, say, 2x as expensive; who would mind? Make barbecue coals as expensive as the meat; would anyone notice? Also, enforce it globally, including places like India, Russia, or China, the latter critically dependent on coal-based electricity.
Now compare to building some walls around glaciers, maybe mere thousands of miles.
I heard somewhere a great parable. Imagine that some aviation specialist would analyze plane hijacking data and recommend to install strong locked doors to pilot cabins on airliners. It would have prevented 9/11, saved thousands of lives, and would have been incomparably cheaper than all those security measures implemented in the aftermath. But likely every airline would be against this unneeded expense, and it would be very hard to push this measure.
Same thing with the global warming, wars, and various other (impending) catastrophes: people hope that they'll get by somehow; how bad it can really be? You see, nothing is happening! When it hits, the view changes drastically, but it's too late already.