After reading this again, it sounds overly harsh. I mean, sure, but its not the point. He still is very much an environmentalist, much like the ones I grew up with that loved nature and thought there was a place for people in it.
Yes, he quit because Greenpeace had been hijacked by the left for its own purposes and these began to result in the deaths of humans and imposing solutions which had nothing to do with making this world a better place to live.
He also quotes in a greater context just what is happening on the long time scale. That we are in the midst of a 2 million year ice age at this very moment that has only relented in the last 8000 years. However, normally, in all of the Earths history, the temperature has been much higher because the poles were mostly not covered with Ice over the last 5 Billion years.
He also points out that each degree of additional warmth is a blessing, as it makes it possible to grow more food! If it starts cooling again, starvation and suffering will be the norm and there are some who think this is desirable.
He also points out how the left is blocking the introduction of life saving grains into the third world in its efforts to resist "Capitalism."
“he quit because Greenpeace had been hijacked by the left”
John Coleman says the same thing about The Weather Channel, except he didn’t name the hijackers.
And David Horowitz says that about the Democrat Party in his book
“The Shadow Party: How the Democrat Party Was Hijacked by George Soros, Hillary Clinton and the Sixties Leftists (Amazon - co-authored by Richard Poe)