I think we have a very brief window of opportunity to deal with climate change. No longer than a decade at most.

Jail threats did not dissuade Martin Luther King - and intergenerational justice is a moral issue of comparable magnitude to civil rights.

The danger is that the compromises and special interests inherent in Kyoto-style targets and cap-and-trade will be accepted because of bureaucratic momentum.

The forcings that drive long-term climate change are not known with an accuracy sufficient to define future climate change.

Talking nice about sun and wind and green jobs is just greenwash.

...chief executives of large fossil fuel companies to [should] be put on trial for high crimes against humanity and nature; [Hansen] accusing them of actively spreading doubt about global warming in the same way that tobacco companies blurred the links between smoking and cancer.

Several times in Earth's history, rapid global warming occurred, apparently spurred by amplifying feedbacks. In each case, more than half of plant and animal species became extinct. New species came into being over tens and hundreds of thousands of years. But these are time scales and generations that we cannot imagine.