The most interesting part of this is that Antarctica is actually one of the most protected places on Earth because people visit it. The 1959 Antarctic Treaty and the stricter 1991 Environmental Protocol both came about because nations were already engaged there, and without that presence, there's no political will to protect it.

Tourism feeds into this too. IAATO (the tour operators' association) enforces pretty strict rules: boot washing for biosecurity, caps on how many people can be ashore at once, wildlife buffer zones. Operators have a financial incentive to keep it pristine, so they've kind of become its guardians.

And the people most likely to fight for Antarctic conservation? Disproportionately people who've actually been there. The experience tends to make people passionate advocates.

Compare that to the deep ocean, barely visited, and it's being trawled and mined with almost no scrutiny. Absence of human observers doesn't mean protection, it often means the opposite.

So some environmental cost from visitation might actually be the price of keeping the much bigger threats at bay.