I wonder what it's like to grow up in a world you know was trashed -- likely to have more plastic in the ocean than fish, wars over resources, hundreds of millions of people displaced from their homes, population decreases, etc... all consequences of past generations' carelessness. Maybe not all those things will happen, but some will. That has to factor into your world view and behavior.
The world is more prosperous and peaceful now than any time in human history. To be born now in a developed country (of which there are far more of than even ten or twenty years ago) is an incredible advantage compared to what the vast majority of humans ever experienced.
He also says that "the luckiest person in the world is the baby born today in this country [USA]."
He's a tremendously optimistic fellow, still working as far as I can tell, and reading 5-6 hours a day at age 87. Highly recommend his interviews on talks.