DAve, she/he's making exactly the point I made but in a rather more oblique, olive kind of way. In other words, it depends on how you define environmental degradation. One individual is (arguably) capable of causing damage. Whether or not it would be reversible could be discussed but in practical terms, it comes down to how much money you want to spend on reversing environmental damage. Ultimately, there must be a limit to this ie no amount of money can bring back an extinct species but to some extent there is a relationship between how much you want to spend on the environment and how many people you can support here.
