All respect for the man, but fortunately we can like and respect somebody without agreeing with them.
You get set in your ways with age. Some of his responses are a bit too much of the type "young people these days!"
Young people may get carried away at times but important changes tend to happen due to young people. Young people led the French revolution and other revolutions advancing democracy and freedom.
A lot of the good things that has happened through the environmental movement has happened due to young engaged people. It is not enough to sit in a lab and invent solutions if nobody listens to you.
Sure I have seen environmental movement ebb and flow ever since the 80s. However it would be silly to suggest that this somehow invalidates them. These organizations helped save the ozone layer, whales and other species. They paved the way for the revolution within renewable energy.