"Turning CO2 into fuels is exactly what photosynthetic organisms have been doing for billions of years, although their fuels tend to be foods, like sugars. Now humans are trying to store the energy in sunlight by making a liquid fuel from CO2 and hydrogen—a prospect that could recycle CO2 emissions and slow down the rapid buildup of such greenhouse gases in the atmosphere. "You take electricity and combine CO2 with hydrogen to make gasoline," explained Arun Majumdar, director of the Advanced Research Projects Agency–Energy (ARPA–e) that is pursuing such technology, at a conference in March. 'This is like killing four birds with one stone'—namely, energy security, climate change, the federal deficit and, potentially, unemployment."