RIO DE JANEIRO, BRAZIL - JUNE 19: A littered section of Guanabara Bay is seen on June 19, 2012 in Rio de Janeiro, Brazil. The bay once held a healthy ecosystem, large fishing stocks and clean beaches, but deforestation and urban development have left the waters littered with debris. A large oil leak in 2000 spilled around one million liters of crude oil from an underwater pipeline into the bay. Following 1992’s Earth Summit in Rio, a $1 billion program was implemented to clean up the bay, but that goal has still not been met. Over 100 heads of state and tens of thousands of participants and protesters will descend on Rio de Janeiro, Brazil, June 20-22 for the high-level portion of 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 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 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.