Worldwide energy demand for air-conditioning (AC) is expected to triple by 2050, requiring added electricity capacity equivalent to today’s combined output of the U.S., the European Union, and Japan, says a new report by the International Energy Agency (IEA). Today, just 8% of some 2.8 billion people living in the hottest parts of the world have AC, while 90% of residents of the U.S. and Japan enjoy AC. The expected global growth would mean 10 new AC units sold every second for the next 30 years, IEA says. The agency predicts the new electricity demand could greatly increase greenhouse gas emissions and consume electricity needed for economic expansion. IEA sees efficiency as the means to curb such negative effects. AC efficiency, however, varies widely. For example, AC units sold in Japan and the European Union are typically 25% more efficient than those sold in China or purchased in the U.S. IEA recommends that countries set higher AC energy performance standards.