Two names should have clued you in: Jared Diamond and National Geographic. Both are about as far to the left as possible. Nat Geo gave up honest science about 25 years ago to beat the drum for “green” propaganda. Diamond’s just another academic environmental shill.
The History Channel has made the same move over the last 7-8 years. They have a 2 hour 'History of the KKK' that fails to mention its intimate connections to the democrat party.
NatGeo still has good programs about space, etc., but you are right on the leftward shift to the 'Church of Global Warming'.