A new study by an international team of 35 scientists and researchers has revealed that the Amazon rainforest has been degraded by a much greater extent than previously believed, with more than a third of the remaining forest affected by humans. The study, published in the journal Science, shows that up to 38% of the remaining Amazon forest area, equivalent to ten times the size of the UK, has been affected by some form of human disturbance, causing carbon emissions equivalent to or greater than those from deforestation.
The research is the result of the AIMES (Analysis, Integration and Modelling of the Earth System) project, linked to the Future Earth international initiative, which brings together scientists and researchers who study sustainability. The study is based on an analytical review of previously published scientific data, 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. The authors evaluate four key disturbances driving forest degradation: forest fire, edge effects, selective logging, and extreme drought. Different forest areas can be affected by one or more of these disturbances.
“Despite uncertainty about the total effect of these disturbances, it is clear that their cumulative effect can be as important as deforestation for carbon emissions and biodiversity loss,” said Jos Barlow, a professor at Lancaster University, UK, and co-author of the paper.
The scientists assessed that the degradation of the Amazon also has significant socioeconomic impacts, which should be further investigated in the future. “Degradation benefits the few, but places important burdens on many,” says Dr. Rachel Carmenta, a co-author based at the University of East Anglia, UK.
In a projection made by the team for 2050, the four degradation factors will continue to be major sources of carbon emissions into the atmosphere, regardless of the growth or suppression of deforestation of the forest. “Even in an optimistic scenario, when there is no more deforestation, the effects of climate change will see degradation of the forest continue, leading to further carbon emissions,” said Dr. David Lapola, leader of the study and researcher at Unicamp.
The authors propose creating a monitoring system for forest degradation, as well as prevention and curbing of illegal logging and controlling the use of fire. One suggestion is the concept of “smart forests” which, like the idea of “smart cities”, would use different types of technologies and sensors to collect useful data in order to improve the quality of the environment.