Life may be beautiful and good, but I'm sure if we probed our respective ethical intuitions--even after subjecting them to reflection--we'd agree that an ant's life isn't as worthy of ethical consideration as a dog's, or a human's. In short, I believe life's value must be correlated with sentience or consciousness, and I also believe that everyone who is honestly venturing forth what they believe (rather than doubting someone else) also believes the same, and I'd love to see a counterexample of someone truly believing differently.

>how many additional people would make destroying the Great Barrier Reef worth it? If clearcutting the Amazon rainforest would increase the population cap by N, for what values of N would you do it?

Just want to say, I think we are all in just as much of a position to have to answer questions such as these as the parent commenter. We can't get away from tricky ethical questions simply because they're difficult.

We can even recognize that something's going wrong if we think we need to answer such stark utilitarian tradeoffs, but that's _still_ not a complete answer. Tricky questions like yours are inherent in the _world_, and it just so happens that the default "answer" to such questions is simply to cover one's eyes and pretend they don't exist.