Not good. This has a domino effect. No oxygen in the oceans means no fish,which means no food source.
That is exactly what we are doing , and I am sure everything will be great again after we are gone! Give the Earth a little time and she will be better off without us. The planet isn't going anywhere. We are the bad guys. Like it or not. Humans are the worst thing we know of to ever come along. If there is a god I am sure he is not claiming us. He is hiding out somewhere pretending he don't know us.
Even though this is the actual solution you constantly hear about fear of population decline. Oh no people aren't having kids. Maybe it's for the best.