Ecuador’s Tungurahua volcano spews a large cloud of gas June 3, 2012. The Tungurahua volcano has started emitting great explosions of ash on its north-eastern side. REUTERS/Carlos Campana (ECUADOR – Tags: ENVIRONMENT DISASTER)

In this May 29, 2012 photo, a vulture flies over Jardim Gramacho, one of the world’s largest open-air landfills, in Rio de Janeiro, Brazil. Jardim Gramacho, a vast, seaside mountain of trash where thousands of people made a living sorting through the debris by hand, is closing after three decades in service. (AP Photo/Victor R. Caivano)