Jim Hansen has been head of NASA's Goddard Institute for Space Studies for 31 years. In this time, he's been arrested twice. Why? How?

Because, as he tells Scientific American today, he believes the White House is ignoring its own agency's alarming data on the state of the Earth's environment.

Both arrests happened during protests against mountain-top removal coal mining. Above you can watch his speech at the Appalachia Rising in September 2010, where he delivered this bon mot: "We are in danger of becoming the land of the rich and the home of the bribe." After the talk, he was arrested along with 100 others for failing to obey an order to disperse.

Hansen testified before congress twice in the '80s about the implications of global warming. After that, he tells Scientific American, he stayed away from activism so he could concentrate on doing science. By 2004, he had produced so much science that made it clear the environment was in grave danger, and the government was doing so little about it, that he dove back into speaking out.

On one hand it's heartening to see that despite Hansen's outspoken shenanigans, he's kept his government job for more than three decades (although: was his break in the '90s and aughts really just because of science?). On the other hand, it's distressing that still, neither party will take a strong stand on climate change. And we're running out of time:

We really should be aiming to keep CO2 no higher than about 350 parts per million and possibly somewhat less than that if we want to maintain stable ice sheets and stable shore lines and avoid many other issues. That would require starting today. We'd have to reduce CO2 emissions at six percent a year if we began next year. If we began five years ago, it would've been three percent. If we wait until 2020, it becomes 15 percent. So if we're hoping to maintain a planet that looks like the one that humanity has known, we're out of time right now.

[Scientific American]