While the public is coming to grips with the reality of human-caused climate change, the scientific and engineering communities failed miserably to shape energy policies that could have minimized climate impacts, says energy expert James Hansen, a longtime climate advocate. Their greatest failure was adoption of renewable portfolio standards — rather than clean energy portfolio standards — and exclusion of nuclear power as a clean development mechanism. Science and engineering can still help minimize the consequences of climate change, he says, but it will require promptly overcoming political obstacles to effective policies. Hansen will provide an overview and offer suggestions moving forward.