That is probably why we are not on the same page here. I'm thinking in terms of the actual harm. Someone rolling coal near me is causing violence to me. The damage to the environment is more difficult to quantify, and that is not the angle I would approach it from.
One common libertarian solution for something unproven would be "it's your job to purchase insurance for this new way of doing things, and convince an actuary that it's safe; the insurance premiums will stop you from taking risks with unproven technologies without appropriate precautions/testing/etc".
Not really. They support it in terms of individual responsibility and not as a government role.
> The standard libertarian solution for something unproven would be "it's your job to purchase insurance for this new way of doing things"
No libertarian I'm aware of would force someone to purchase insurance. But it also does not address the externalities problem. We have in this thread an example of an externality that doesn't have a solution. Rolling coal does small amounts of damage. An insurance agent would be happy to insure someone with a modded car that rolls coal because there isn't going to be a claim related to it.
The same is true for any CO2 emitting activity. The damage is an externality that builds up with very small individual acts. I know of no way this would be addressed with libertarian philosophy (grant for me that man-made climate change is real and a problem if you want to argue against this).
To a libertarian, a major part of the government's job is to enforce contracts and property rights. Externalities are mass infringements on other people's property rights, that need to either be avoided or appropriately compensated. Emitting CO2 does damage to a common good everyone has an interest in.
> No libertarian I'm aware of would force someone to purchase insurance.
I didn't say the government would force them to. (Though some smaller-scale voluntary association might well do so.)
Like, let's say I have a slam dunk case that my $1000 tree died due to climate change. I have the receipts, documentation, everything (unrealistic as it is). How would I go around recovering the damages I'm owed? Who would figure out that "Ted there who drove to work for the last 20 years contributed $0.0001 of your damages. The concrete plant over there contributed $0.001. The coal plant $0.01".
I'll also point out you did not address the rolling coal problem.