RONDON DO PARA, BRAZIL - JUNE 08: A worker carries a bag of charcoal produced from illegally harvested Amazon rainforest wood up a ladder onto a truck on June 8, 2012 in Rondon do Para, Brazil. According to a recent Greenpeace study, illegal wood charcoal is primarily used in Brazil to power smelters producing pig iron, which is used to make steel for industries including U.S. auto manufacturing. Illegal charcoal camps were found to sometimes result in slave labor and the destruction of rainforest on protected indigenous lands. Between 2003-2011, 2,700 charcoal camp workers were liberated from conditions akin to slavery, according to Greenpeace.  The workers in this photo said they were paid $40 per truckload of charcoal.  The Brazilian Amazon, home to 60 percent of the world’s largest forest and 20 percent of the Earth’s oxygen, remains threatened by the rapid development of the country. The area is currently populated by over 20 million people and is challenged by deforestation, agriculture, mining, a governmental dam building spree, illegal land speculation including the occupation of forest reserves and indigenous land and other issues. Over 100 heads of state and tens of thousands of participants and protesters will descend on Rio de Janeiro, Brazil, later this month for the Rio+20 United Nations Conference on Sustainable Development or 'Earth Summit'. Host Brazil is caught up in its own dilemma between accelerated growth and environmental preservation. The summit aims to overcome years of deadlock over environmental concerns and marks the 20th anniversary of the landmark Earth Summit in Rio in 1992, which delivered the Climate Convention and a host of other promises. Brazil is now the world’s sixth largest economy and is set to host the 2014 World Cup and 2016 Summer Olympics.  (Photo by Mario Tama/Getty Images)