PARA STATE, BRAZIL - JUNE 09: Federal highway BR-222 is seen on June 9, 2012 in Para state, Brazil. Highway construction through Amazonian rainforest has led to accelerated rates of deforestation. Although deforestation in the Brazilian Amazon is down 80 percent since 2004, environmentalists fear recent changes to the Forest Code will lead to further destruction. Around 20 percent of the rainforest has already been destroyed. The Brazilian Amazon, home to 60 percent of the worldas largest forest and 20 percent of the Earthas 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 worldas sixth largest economy and is set to host the 2014 World Cup and 2016 Summer Olympics.