An unprecedented mapping made using artificial intelligence estimated the presence of 3.46 million kilometers of roads cutting through the Legal Amazon — of these, more than 3 million are not official roads. The extension is nine times the distance between the Earth and the Moon (384,400 kilometers).
Considered one of the main vectors of the deforestation and burning process, they are roads built by loggers, prospectors, squatters, in addition to land owners — often from official highways. They cut, in many cases, forests still preserved on public lands, conservation units and indigenous lands.
The estimate was made in an article published in the specialized journal Remote Sensing, at the beginning of the month, by researchers from Imazon (Instituto do Homem e Meio Ambiente da Amazônia). The authors worked with an algorithm designed to detect rural roads from satellite images for the year 2020.
With the method, it was possible to obtain a level of identification of roads much superior to investigations made previously based on the visual interpretation of the satellite images by the analysts. Pathways almost imperceptible to the naked eye have been mapped by artificial intelligence. In some regions, up to five times more roads were detected than could be mapped with visual interpretation.
According to the survey, most roads (55%) are on private land, 25% on public land, 12% on rural settlements, 2.6% on indigenous lands and about 5% on state and federal conservation units. .
Official federal government databases point to the existence of only 39,000 km of roads in the Amazon, 25,000 of which are state and 14,000 km are federal. These are the so-called official roads. In a previous study by the Imazon group, they had already found over 100,000 kilometers of secondary roads open only in settlements.
But these analyzes of satellite images had only considered the area of the Amazon biome and had been done with another methodology and manually, which makes it impossible to make a numerical comparison of the evolution of the opening of new roads with the artificial intelligence model.
The idea now is to apply this algorithm to previous years in order to reconstruct a historical series. The available data, however, already make important revelations.
“Of what we have of remaining forest in the Amazon [3,1 milhões de km²], 41% are cut off with some road. These are the areas with the greatest risk of deforestation”, says Carlos Souza Jr., a researcher at Imazon and coordinator of the work.
He explains that the opening of roads is the first step of occupation, generally started with a process of predatory logging. “This wood will finance deforestation. The roads penetrate protected territories, feed the mining”, he says.
“We have already identified that many roads are penetrating the most forested areas of the region. There are more roads in the south of Amazonas, in the west of Pará and in Terra do Meio, also in Pará. An important number of the study is that almost 25% of the roads mapped areas are on public land with no destination. This works as an early warning that these areas are under pressure from land grabbing. The pressure of roads in protected areas is also high”, he adds.
He explains that many are newly opened roads, which can be attested in a later visual analysis of the images because they have a lot of forest around them – unlike the older ones, where little or nothing is left.
“This clearly indicates the expansion of new frontiers of occupation in the Amazon”, he says.
Several previous studies had already revealed how the opening of roads, whether official or not, is a vector that drives deforestation. One of the studies pointed out that 95% of deforestation and 85% of fires in the Amazon are concentrated in a corridor of up to 5.5 kilometers along roads.
“When we ran the same model to assess the correlation between distance from roads and deforestation with the new data obtained with artificial intelligence, we saw this distance drop to 2 kilometers”, says Souza Jr.
A recent example of this impact is the increase in deforestation around the BR-319, which connects Manaus to Porto Velho, in the region known as Amacro (where 32 municipalities are located on the border of the states of Amazonas, Acre and Rondônia).
The expectation of paving the open road in the 1970s has led to an explosion of forest clearing, especially in southern Amazonas, which was better preserved. The cities of Lábrea and Apuí lead the ranking of alerts by Deter, by Inpe, between August 2021 and July 2022.
For the researcher, new policies to combat future deforestation will need to act in this process of opening roads. “It is necessary to cut these arteries of destruction. They are the ones that will give access to natural resources that, later, will finance the destruction of the forest”, he says.
The Planeta em Transe project is supported by the Open Society Foundations.
