I was lucky to grow up at a time when it was not difficult for the child of a tenant farmer to make his way to the state university.

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.

I was lucky to grow up at a time when it was not difficult for the child of a tenant farmer to make his way to the state university.

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

Coral reefs, the rain forest of the ocean, are home for one-third of the species of the sea. Coral reefs are under stress for several reasons, including warming of the ocean, but especially because of ocean acidification, a direct effect of added carbon dioxide. Ocean life dependent on carbonate shells and skeletons is threatened by dissolution as the ocean becomes more acid.

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.

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