There are 1.2 billion room air conditioning units installed today, but that figure will soar to 4.5 billion by 2050, according to an RMI report. "The impact of that on electricity demand is going to be huge," said Campbell, who co-authored the report. "The dilemma is that it comes at an environmental cost we can't afford. It's a kind of climate threat you don't see much in the rear view mirror, but when you look at what's in front of you, it's massive,"The Global Cooling Prize sets specific guidelines for participants, who were tasked with designing a cooling solution with five times less climate impact than those popular today, meaning they could help counteract the environmental effects of the expected growth in demand.