Even if we get carbon under control (unlikely), demands for food will continue to strain the ecosystem. It will take time, but as I pointed out, women in developed nations are opting to have fewer (if any) children. If that trend continues, the population will probably start to decline. Loren on TMF thought it would peak around 8-9B, and then reverse.

Maybe? I mean, not necessarily?

Right now, we're at just under 8 billion. Global population projections vary, but generally speaking we're pretty likely to peak at around 10 billion (give or take). Total Fertility Rates have been dropping since the 1960's, so there's not all that much growth left in the ol' Population Bomb.

Meanwhile, though, total global food production is about a third higher than global food requirements. I mean, it's more complicated than just looking at total caloric generation vs. needs - food distribution is heavily uneven geographically and across income levels (both between and within countries), and there are some nutrients that are more adequately produced than others.

frontiersin.org: Frontiers | Nutrient Adequacy of Global Food Production

But by and large, at the highest level of generalization, we are today producing more food than we will need in order to feed everyone even at the peak of global population. Malthus was wrong, and will never ever be right.

Now then - does that mean we're out of the woods? Of course not - human choices have an enormous impact on the environment, and people were perfectly capable of destroying fisheries and herds even without any demographic need to do so. But it means that such environmental damages are not the inevitable consequence of having "overpopulation." They're the result of our societal and economic choices, not the destiny of limited resources or biology.