As species are exterminated by shifting climate zones, ecosystems can collapse, destroying more species.

The last time the world was three degrees warmer than today-which is what we expect later this century-sea levels were 25m higher. So that is what we can look forward to if we don't act soon.

The scientific excitement in comparing theory with data, and developing some understanding of global changes that are occurring, is what makes all the other stuff worth it.

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.

If we fail to act, we will end up with a different planet.

The evidence for human-made climate change is overwhelming.

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