James Hansen, Acclaimed Scientist, Retires From NASA to Campaign In Fight Against Climate Change and Global Warming

Nearly 50 years after he started his career with NASA in the field of planetary and climate research, one of NASA's greatest and brightest decided it was time to step away in order to take up the fight against global warming.

James Hansen, a climate scientists of 46 years with NASA, will be retiring on Wednesday in order to more actively campaign against global warming in a way that won't be hindered by the rules of his longtime government job with NASA, the New York Times confirmed.

"As a government employee, you can't testify against the government," he told the Times in an interview.

Hansen, director of the Goddard Institute for Space Studies, famously entered the public eye in 1988 when he testified to Congress about the dangers of global warming. Since that time, his views on global warming have clashed at times with the administrations of presidents in the Oval Office, most famously with the Bush administration in 2005.

When a Bush administration aide tried to screen Hansen's comments to reporters, Hansen fought back by making the fight public, causing the administration to back off.

In an interview with NPR in 2009, he expressed his frustrations about dealing with Washington when it comes to the issue of climate change.

"After spending three or four years interacting with the Bush administration, I realized they were not taking any actions to deal with climate change," he told NPR. That's when he decided he didn't want his grandchildren to say of him someday that he "understood what was happening but he didn't make it clear."

Now, at 72 years old, Hansen is more determined then ever to raise awareness on global warming, noting the dangers that unchecked burning of fossil fuels will have on the environment inherited by future generations.

"If we burn even a substantial fraction of the fossil fuels, we guarantee there's going to be unstoppable changes" in the climate of the earth, he told the Times. "We're going to leave a situation for young people and future generations that they may have no way to deal with."

Hansen says that he intends to keep publishing papers in academic journals and will likely work in a small institute or take an academic appointment.