Injection of environmental and political perspectives in midstream of the science discussion cannot help the process of inquiry. I believe that persons with relevant scientific expertise should concentrate, with pride, on cool objective analysis, providing information to the public and decision-makers when it is found, but leaving the moral implications for later common consideration, or at most for summary inferential discussion.

We have at most ten years - not ten years to decide upon action, but ten years to alter fundamentally the trajectory of global greenhouse emissions... We are near a tipping point, a point of no return, beyond which the built in momentum and feedbacks will carry us to levels of climate change with staggering consequences for humanity and all of the residents of this planet.

Recent warming coincides with rapid growth of human-made greenhouse gases. The observed rapid warming gives urgency to discussions about how to slow greenhouse gas emissions.

The 5-year mean global temperature has been flat for the last decade, which we interpret as a combination of natural variability and a slow down in the growth rate of net climate forcing.

Money has too big an influence on our politics in Washington and somehow we need to do something about that.

A level of no more than 350 ppm is still feasible, with the help of reforestation and improved agricultural practices, but just barely - time is running out.

...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.