Malthus doesn't get a lot of love around here, but looking around it kind of seems like he was more right than wrong. We're overfishing the oceans leading to huge declines in large fish. Insect populations seem to be crashing. And there's also climate change, etc.

The techno-optimists will counter that there are technical solutions for all of of our problems, but it seems that a lot of these issues actually require political will that just isn't there; humans generally don't have the longterm outlook required to fix many of these things on a global scale. Politicians who try to get us to take a longer view don't seem to last long in our political systems.

So yeah, I guess the earth could probably handle more people, but that's only if those people take a much longer view and intentionally try to live much more lightly on the earth - I don't see that happening so I have to conclude that Malthus' thesis seems to (unfortunately) be correct given the reality of human nature. Changing human nature isn't something technology is going to be able to do.