• Scenario 1

I build my factory next to your land. A byproduct of my factory is a bunch of polluted water, which drains strait onto your land, causing much damage.

The tort system could deal with this fine [1]. You can easily prove that it was the pollution from my factory that damaged your land.

This may not be a good way to deal with it, because (1) it takes effort to take someone to court, which many small landowners may not have the time for and so will discourage them from defending their property rights, and (2) it assumes that only the monetary value of your land is important and thus it is OK for someone to damage your land as long as they pay.

• Scenario 2

I build my factory 1000 miles from your land. My polluted water runs into a nearby river, eventually makes it to the ocean, and some of it eventually ends up on your land.

The tort system is useless to address your injury. There are too many chaotic physical processes between the emission of the pollution at my end and the arrival of pollution at your end for you to prove that any of that pollution came from me. If you sue me, my defense is that there are hundreds or thousands of other factories polluting, and for all we know all of my pollution either stayed in the ocean or when it got back to land ended up on land other than yours.

If we modify the tort system so that in the case of pollution we turn the burden of proof around and require the defendant to prove that they did not pollute the plaintiff's property, then you can sort of make it work.

But if we do that, now we've just turned the problem around. It will be almost impossible for me to prove that my pollution did not reach any given plaintiff. Anyone who finds pollution of the type that my factory produces can easily and successfully sue me.

If that's the case, then as soon as you sue me, I'll be filing third party complaints against all the other factories that emit the same kind of pollution, alleging that they are equally responsible for the pollution that damaged you.

Of course, you won't be the only plaintiff suing me, since pollution spreads far and wide from the source. And all of the defendants will be filing third party complaints against all the other defendants. So we'll end up with a bazillion lawsuits, each consisting of one plaintiff with damaged land, and thousands of factory owner defendants. Someone will try and succeed in turning this into a class action.

The class plaintiffs will win, damages will be accessed will be accessed with each factory's share probably proportional to the amount of their pollution, and split among the plaintiffs proportionally to the damage to their land. This only settles things among those defendants and the plaintiffs that are in the class, so this thing will have to be repeated when new plaintiffs arise or new factories are built.

The net result will be that instead of a simple, straightforward, approach of the legislature creating a pollution fee or tax with the proceeds going to pollution cleanup, with the executive handling enforcement, we end up with an ad hoc sort of equivalent cobbled together from the tort system that is costlier, more time consuming, and has a lot more uncertainty (and still needs legislative action to create because it depends on changing the burden of proof in pollution cases).

[1] By "deal with it fine", I mean identify the party responsible for the pollution and make them pay monetary damages. One can make a good case that this is not actually fine, for at least two reasons. First, it assumes that only the monetary value of land is important. Land often has esthetic or sentimental value to people, which they would not give up even for much much more money than anyone else would pay for the land. Second, it takes time and effort to sue someone. Many small landowners would not have the resources for that, and so would have to just suck it up and accept the pollution.