Walter is an environmental analyst at the Brazilian Environmental Institute (ICMBio), with a degree in business administration. Before joining the government, he worked for Greenpeace and was a co-founder of the Brazilian environmental NGO - Pró Bocaina. Subsequently, he spent 10 years managing Federal Protected Areas in the Amazon and in the Atlantic Rainforest. From 2005 until 2012 he was the manager of Itatiaia National Park, the first national park created in Brazil. His most recent efforts are focused on applying new and sustainable alternatives to managing Protected Areas that simultaneously protect forests and biodiversity and improve the livelihoods of people living in and around the protected areas.
In 2013, he was invited to spend a year as a visiting scholar at the Center of Environment, Economy and Society (CEES) of Columbia University in New York. After returning to Brazil, he was designated to coordinate a working group on Forest Carbon Credits at ICMBio and to supervise a demonstrative project to test the implementation of The Rainforest Standard for Protected Areas aiming to generate high quality forest carbon credits. The protected area chosen is a 1,800,000 acres sustainable use area in the Amazon, where 4,700 families live in 74 communities.