This video was created by Sustainable Human as a gift to humanity.
When whales were at their historic populations, before their numbers were reduced, it seems that whales might have been responsible for removing tens of millions of tonnes of carbon from the atmosphere every year.
The return of the great whales, if they are allowed to recover, could be seen as a benign form of geo-engineering. It could undo some of the damage we have done, both to the living systems of the sea, and to the atmosphere.
Another example of a “trophic cascade” can be seen in this video How Wolves Change Rivers.