If he did, would you mind sourcing it? Until then I don't see a reason to believe you, as you yourself say you didn't watch the movie.
He said sea levels could be 20 feet higher in the near future. Which could only be right if we’re talking hundreds of years…
Hundreds of years is kind of the near future with respect to the ~300,000 years we've existed (H. Sapiens, and tools) and the ~30,000 years since we started to 'civilize' (art, descriptive cave paintings) even relative to agriculture (12,000 BP)