This is James Hansen, a "scientist" who has an ego bigger the hole in the ozone layer. He parades around scaring politicians into believing that Global Warming exists.
He even accused the Bush League Administration of using NASA to try to silence him from warning of the dangers of Global Warming.
Has this snake oil scientist always believed in Global Warming?
Well, not according to this editorial. In 1971, Hansen warmed of the coming Ice Age!
Read more about it here.