Well... other than ourselves!
I'm certainly no expert on population, but I did listen to an authoritative news report saying that at present, the earth does not have the resources to feed everyone with a well balanced, nutritious diet. More and more, I'm happy that I bought 40 hectares for my home 30 years back. The half that's forest is doing it's part to produce oxygen, and the half that's unforested will become a place to grow crops in the future (except for the part that's my runway
). If the past autumn is any indicator, rain water for crop growth won't be a problem in the future! But I think about my time in the Maldives, and other low lying places, and the fact that the rising ocean is really going to threaten such places.
Embarrassingly, I live in a nation where driving immense pick up trucks and SUV's for personal transport is considered necessary. As I economize my way along in my diesel VW, I cringe at the thought of all that gasoline being wasted hauling around an extra ton of vehicle to carry one person to work each day! Fuel burners don't see to notice the cumulative effect of carbon fuel consumption on our climate - their kids problem, instead of theirs, perhaps. I hope electric vehicles catch on more soon!