Haha, will go look at that!
Joke aside, if women had always been free and not oppressed under patriarchy, (a natural state which MRAs would certainly described as women ruling the world) then we would not have an overpopulation problem.
Which would mean most environmental problems we have nowadays would not exist.
We would also not have wars, because without conflict over territories and resources, there's no reason for wars.
Women taking over would need a long time to fix all the problems, but I imagine it would immediately help some.
And Donald Trump would not be president, because his grandfather made his money with brothels, which with free women would not have been possible.