Idea for a novel :

Aliens come to earth. They tell us that there are only 37 planets in our galaxy with life on them. 13 have sentient life. 4 have space travel and advanced technologies. Those four have made an agreement that none of these last remaining 37 precious planets can be destroyed, and they will do anything they can to keep all those planets safe.

So, finding our planet on the brink of mass extinction, they have come to save us. In one year they are going to turn off all the machines and technologies which are tipping the ecological balance.  Individual species they’re not concerned about, so we can keep hunting whales and killing each other. But they won’t let us bring down the whole ecosystem.

Aliens coming to save usThe people whose wealth and comfort relies on coal and oil start a war against the aliens. It’s just like the tripods trilogy, except they are trying to help us.

I’m not sure how the story ends, but it’s possible that in the end, the only thing they can do to save the planet is kill all the humans and let the other species evolve as they will.