People light candles during Earth Hour after lights were turned off in Cali March 31, 2012. Lights started going off around the world on Saturday in a show of support for renewable energy. REUTERS/Jaime Saldarriaga (COLOMBIA - Tags: ENVIRONMENT SOCIETY TPX IMAGES OF THE DAY)
Children light a candle while marching during Earth Hour in Lima March 31, 2012. Lights started going off around the world on Saturday in a show of support for renewable energy. REUTERS/Enrique Castro-Mendivil (PERU - Tags: ENVIRONMENT SOCIETY)
Children march while holding candles during Earth Hour in Lima March 31, 2012. Lights started going off around the world on Saturday in a show of support for renewable energy. REUTERS/Enrique Castro-Mendivil (PERU - Tags: ENVIRONMENT SOCIETY)