Because the current climate spending is extremely inefficient and stupid. For example, if we put all this effort into making more energy, e.g. making nuclear actually work, we could soon make the climate do what we want, not the other way around.
And of course anything the government gets involved in will get screwed up, so just stop screwing it up and let the bright people do what they are passionate about.
Imagine regulatory asphyxiation disappears. Imagine energy tech gets its own Moore's law. Imagine cheap abundant energy, say 10 orders of magnitude from now in a few decades. Heating up or cooling down the planet at will doesn't sound impossible then.
So we should just hope this all away? That's a deeply childish viewpoint, and hoping is not a reliable plan. It will require many things: Carbon regulation plus geo-engineering plus improved power systems plus personal sacrifice. But where that starts is legislation. This is how we solved acid raid, the ozone layer, lead-based fuels and paints, and oh so many other environmental externalities. Individuals cannot solve this problem themselves. I could convert my house to solar and buy electric cars tomorrow and the problem is not solved, because I account personally (through my own choices) of only 20% of the issue.
https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emis...
No, absolutely not! Where it starts is invention and invention is currently severely hindered by regulation, alarmism and skewed incentives. Why would a bright mind work on nuclear physics if you can make more money as a lawyer?
But that's not where we are. Without $$ incentive, nobody is going to build what is needed to remove the carbon or mitigate the effects of warming. The market is not magically going to solve anything if we simply remove regulation, that is a strawman. The market needs incentives, as well as restrictions. When we solved the ozone layer, we first restricted chloroflorocarbons to stop the bleeding, then we added incentives to create replacements. And it worked. It's not alarmism that's the issue here, it's heads in the sand.
And of course anything the government gets involved in will get screwed up, so just stop screwing it up and let the bright people do what they are passionate about.