U.S. energy secretary Steven Chu said Wednesday that the U.S. must decrease its energy use to allow developing nations the room to grow, while emphasizing that prosperity doesn't have to come with a large carbon footprint.
 
"We believe we have to decrease our use of energy to allow headroom for the developing nations to grow their economies," Chu said in a speech in Abu Dhabi, capital of the United Arab Emirates.
 
"There is no law of physics that says prosperity is proportional to carbon emissions," Chu said.