The paper was led by an international team of 35 scientists and researchers, from institutions such as Brazil's University of Campinas (Unicamp), the Amazon Environmental Research Institute (IPAM), National Institute for Space Research (INPE), and U.K.'s Lancaster University. It shows that up to 38% of the remaining Amazon forest area—equivalent to ten times the size of the U.K.—has been affected by some form of human disturbance, causing carbon emissions equivalent to or greater than those from deforestation.

The work is the result of the AIMES (Analysis, Integration and Modeling of the Earth System) project, linked to the Future Earth international initiative, which brings together scientists and researchers who study sustainability.

The findings are the result of an analytical review of previously published scientific data, based on satellite imagery and a synthesis of published data outlining changes in the Amazon region between 2001 and 2018. The authors define the concept of degradation as transient or long-term changes in forest conditions caused by humans. Degradation is different from deforestation, where the forest is removed altogether and a new land use, such as agriculture, is established in its place. Although highly degraded forests can lose almost all of the trees, the land use itself does not change.