He said: "I've really noticed, over the last 20 years, that although we are deeply worried about climate change - and it doesn't seem to be getting better at the moment - that across the world, there are just hundreds of pinpoints of light, of little projects of re-wilding, of all kinds of biological movements that are really very hopeful."
He added that "the power with which nature comes back astounds biologists", stressing how "extraordinary resilient" animals, fish, sea life and plants are "if you just stop doing bad things to them."
It is about "finding that balance", he continued, noting how many people still rely on animals and fish for food.
"So I think human civilization has an element of that too, and we will scrape through."
