Ah, you say, governments are already doing this on their home turf; how could you even have a reverie about international forces in the territory of independent entities?
One of the lessons of Agenda 21 (proposals for sustainable development adopted at the Rio summit) is that there is no independent entity when it comes to environment, that the most hermetic of kingdoms affects or is affected by what is happening elsewhere in the world. It is that principle that should encourage all of us to behave internationally with respect to these matters. The force could wear nice green uniforms, and one of the main tasks it could accomplish would be to make known, loudly in public forums, what governments would either like to keep quiet or argue about defensively.