U.S. Department of Energy Secretary Steven Chu resigned from the Department last Friday. Chu, who turns 65 this month, was a leading advocate for alternative energy development.
"I would like to return to an academic life of teaching and research, but will still work to advance the missions that we have been working on together for the last four years," said Chu in his resignation letter to the President.
He also cited the creation of the Advanced Research Projects Agency-Energy, a government effort to support energy technology development, as a major accomplishment.
"While we cannot accurately predict the course of climate change in the coming decades, the risks we run if we don't change our course are enormous," wrote Chu, "As the saying goes, the Stone Age did not end because we ran out of stones; we transitioned to better solutions."
Chu will stay on as Energy Secretary until the end of February.