Obama's top science adviser has never let politics drown out what he believes research can prove. In the late 1960s, Holdren published a paper alongside Stanford University's Paul Ehrlich—he of The Population Bomb fame—charging that the world's technology would soon be unable to adapt to the pressures of a more crowded planet. Though Holdren's Malthusian predictions failed to hold up in the short term, much of his work since has concentrated on humankind's long-term effects on the globe. Holdren, now 69, has won numerous awards for his work. In 1994, he was named to President Clinton's science advisory team, where he studied fusion energy and ways to secure Cold War-era fissile materials, among other subjects. After leaving the Clinton administration in 2001, the aeronautics engineer and plasma physicist moved to Massachusetts, where he joined Harvard University as the Teresa and John Heinz professor of environmental policy. Eight years later, Holdren returned to the President's Council of Advisors on Science and Technology at the beginning of the Obama administration and has been an outspoken advocate for aggressively dealing with the problem of climate change. Holdren is a graduate of the Massachusetts Institute of Technology and earned his Ph.D. from Stanford University.