Philip Martin Fearnside (born May 25, 1947) is an American biologist and scientist, active for many years in Brazil, where he developed the most important part of his career and gained wide national and international notoriety.

[1][2] Fearnside has a large published bibliography (http://philip.inpa.gov.br), which includes studies that contributed to the increase of the knowledge about the fires, the capacity of human support in colonization areas, the rhythm, environmental causes and impacts of deforestation in the Amazon; for the development of techniques for sustainable management of nature, and for the renewal of methodologies for assessing greenhouse gas emissions, among other topics.

He began his professional career as a graduate student, leaving for Asia as an agent of the Peace Corps, a technology and humanitarian aid body of the US government, operating between 1969 and 1971 in the state of Rajasthan, India,.

In 2003, Pesquisa Fapesp magazine published a story about the biologist and reported that "today, three decades after landing in the region, Fearnside accumulates field experience - even lived in villages along the Trans-Amazonian Highway to do his doctorate - and scientific knowledge about the Amazon rarely found in Brazilians [...] His name is an international reference in many of the themes that make the great tropical forest an important and controversial subject, such as the possible relation between forest deforestation and climate change on the planet and the impact of the implementation of roads, dams and agricultural projects in the region.

For his work in favor of sustainable development against offensive projects to the environment, such as the construction of the Balbina Dam power plant in the 1980s, he is often challenged by supporters of progress.