Amazon road-building projects would result in deforestation of 2.4 million hectares

by Bob Yirka , Phys.org

Credit: CC0 Public Domain

A team of researchers from the U.S., Bolivia, Brazil, Sweden, Peru and Columbia has found that most of the road projects currently planned for the Amazon rainforest have not been assessed for environmental or economic impacts. In their paper published in Proceedings of the National Academy of Sciences, the group describes their own assessment of the impact of 75 planned road building projects and what they found.

Despite the critical role that the Amazon rainforest plays in storing carbon, governments in the area continue to approve road building projects, oftentimes without ever assessing the ecological impact of such projects or whether they will even be economically viable. In this new effort, the researchers analyzed 75 road building projects that are slated for the next five years.

The researchers began by noting that the construction of the roads, which together will add up to 12,000 kilometers of roadway, will cost approximately $27 billion. The roads will be built in Columbia, Peru, Ecuador, Bolivia and Brazil. They also note that the rationale for building the roads is to promote agriculture and cattle ranching. To assess the impact of the projects, the team chose to constrain their study to 20 years.

The researchers found that building the roads would result in deforestation of approximately 2.4 million hectares of rainforest. Seventeen percent of the projects are in violation of either environmental regulations or Indigenous rights. They also found that the money spent to build many of the roads would not result in economic gain—instead, almost half of them would experience losses. They found that canceling the ones that they project to experience losses would prevent losses of up to $7.6 billion and reductions of rainforest loss by approximately 1.1 million hectares.

The researchers also ranked the roads by degree of environmental (and social) impact and found that if road planners approved those with the least impact and cut the others, they would see a net gain of $4 billion while cutting the amount of rainforest loss to just 10% of original projections. They conclude that proper assessments of road building projects in the Amazon could reduce the amount of forest cut down and the costs involved

Study of Brazilian Amazon shows 50,000 km of road was built in just three years

More information: Thais Vilela et al. A better Amazon road network for people and the environment, Proceedings of the National Academy of Sciences (2020). DOI: 10.1073/pnas.1910853117