When the option for positive action to mitigate a problem exists, we often don't do it because the action creates legal liability for any and all negative externalities of the action, even if the negative externalities as a whole are drastically less than what would happen doing nothing.
We resist permitting prescribed burns because when they cause unintended damage and harm, there's a person to institution to blame, so no one wants to take on that liability. So instead, we let brush grow out of control and eventually a mega fire hits that creates orders of magnitude more destruction and health hazard than the sum of all prescribed burns ever would have.
Another example is medical treatment. If you develop cancer and die because you get no treatment, there's no person to blame and no one to sue. It's just an "act of god" so people accept the outcome and move on. But if you get treatment and the doctors make a mistake and their actions cause some unintended harm, then there's someone to blame and sue, even if your statistical outcome was drastically improved by their intervention.
The same problem is going to exist trying to mitigate climate change. Positive actions to reverse the problem will create negative externalities that hurt some people, but doing nothing will be drastically worse.
I don't know how we solve this problem. To me, the root of the problem seems to be a weakness of the constitution of our society and/or leaders.
Collectively, we need to figure out how to balance diffuse statistical risk against acute, dramatic risk, or else we all risk being the frog slowly boiled alive.