> The usefulness of the ocean as a thermal sink though depends on water temperature which can vary a lot depending on where you are. No. The difference between

> The usefulness of the ocean as a thermal sink though depends on water temperature which can vary a lot depending on where you are. No. The difference between pumping water at 15°c or 30°c is negligible when you're cooling water at 325°c. You may have to pump a tiny bit more water, but that's a non-problem when you have an ocean.