I guess the the previous poster is implicitly proposing an international treaty on the atmosphere (edit: maybe creating a new UN specialist agency). Of course, there are already a number of other treaties in this area and while some of them have worked reasonably well (like the treaties to protect the ozone layer by eliminating use of CFCs), others have been fraught with difficulty.

There are already international treaties on water rights, even with dispute resolution mechanisms in some cases, so maybe these mechanisms could be extended somehow to water rights in atmospheric water. (Not that this is by any means easy in the case of surface water.)