"I have a strong sense of responsibility and a duty also to try to show what's happening so people know," Beltra told ABC News' Bob Woodruff this past July in Sumatra. "The wider the audience, the better, so we can do something together to try to solve this problem."
ABC News joined Beltra exclusively as he visited and documented Bukit Tigapuluh, the last remaining lowland forest on Sumatra.
Beltra's work in Indonesia is just one of the latest ventures on a long list of conservation projects that has educated a large global audience and been received with much deserved accolades.
Just this year Beltra was recognized with Prince Charles' Rainforests Project Award, the top prize of the Sony World Photography Awards 2009.
Beltra was hand-picked by the prince to document the world's most beautiful and most endangered rain forests.
"Photographic imagery can tell a compelling story about the truth of the situation, and the truth is, if we lose the fight against tropical deforestation, then we lose the fight against climate change," Prince Charles said in a video message.
Prince Charles' organization aims to combat deforestation with incentives to keep the natural resources intact.
"The idea is to create a fund to compensate the country that still holds the big chunks of tropical rain forest, so the forest is more valuable standing than logged," Beltra said.
Tropical deforestation has struck Indonesia hard. With just 30 percent of its natural forest remaining, it is third, behind China and the United States, in carbon emissions worldwide.
"When I came here for the first time, I was really shocked by the deforestation, and there was basically almost nothing left," Beltra said.
Between 1985 and 2007 Sumatra lost approximately 55,000 square miles of natural forest.
"It's heartbreaking," Beltra said in an interview with ABC News. "The degree of destruction here, it's amazing. … I want people to be aware of what's happening and do something. And in order to do something you need to understand that there's still 80 percent of the rain forest standing and it's so gorgeous. So that's why we need to try to protect that," he said.
When forests are burned or cut down, they release large quantities of carbon dioxide, which affects the planet's climate.
"Tropical deforestation around the world is responsible for 20 percent of the CO2 emissions worldwide, so if we stop tropical deforestation that's a great way to control global warming," Beltra said.
Beltra has seen his share of natural disasters. His work has documented melting icebergs in Antarctica and devastating forest fires in Africa.
But Beltra most vividly remembers the emotion he felt photographing the droughts that ravished the Brazilian countryside. Beltra saw devastation everywhere in a drought that hit the Amazon in late 2005.