"In 1988, he stepped to the front of the line of the scientific community to proclaim a human fingerprint on the earth's rising temperature," Wirth said. "It was a brave, a lonely leadership role he played then and he hasn't stopped for one day since."
At a Washington event recalling that hearing, Hansen said the world has long passed dangerous levels for greenhouse gasses in the atmosphere.
"We really have reached a point of a planetary emergency," Hanson said. "And it is because there are tipping points in the climate system which we are very close to and which, if we pass, the dynamics of the system can take over. So the momentum of the system will carry you to very large changes which are out your control." More >>>