It's OK, for species wide compliance we have war.
* We can go to general, world wide conventional war. Just the amount of oil and environmental damage spent, producing machines (eg, airplanes, tanks, missiles, ships) would be astronomical
* Nuclear war would likely break out at some point, when someone is backed into a corner
* Biological warfare will likely be a component of any large scale future war. Naturally, mistakes will be made, and one favourite is destroying an enemy's food supplies.
So imagine crops or food animals targeted by disease, and it spreads to other lifeforms
My point is, I have been wondering that when things get very very visibly bad, when no one can rationalize away what is happening, when everything is falling apart due to global migration, land loss, loss of crop land, etc etc...
Will war then occur, with "pro environmental" nations working to prevent environmental damage of others? And then, of course, causing waaay more damage due to the war?
Because, well, humans.