Four cities in the state of Rio de Janeiro are among the ten most at risk of landslides in the country. A survey carried out by MapBiomas, which is a network made up of NGOs, universities and technology companies, shows that urbanization in Brazil has more than doubled in the last 40 years. The study was released this Wednesday (4). Along with this growth came risks with the reduction of green areas.
They are: Angra dos Reis, Nova Friburgo, Petrópolis and Teresópolis.
In the last 40 years, Brazil's urban area has more than doubled. Between 1985 and 2025, it grew 132%, going from 1.9 million to 4.4 million hectares last year.
In favelas, the advance of urbanization was even greater: 150%. The urbanized area increased from 60.2 thousand hectares in 1985 to 151.7 thousand hectares in 2025.
"We can, looking at the satellite images on MapBiomas, see that urbanization continues to increase: from 1985 to 2025, it increased around 2.3 times. But the risk has been decreasing, as you have densification, verticalization, this type of thing", said Julio Pedrassoli, coordinator of MapBiomas.
At the same time that concrete advanced, vegetation lost space. In total, 77.6% of the country's communities lost at least 10% of their vegetation cover in 40 years.
The reduction in green areas also has a direct impact on temperature. According to sociologist and urban planner for favelas Alan Brum, measurements taken in communities show significant differences compared to the surrounding area.
"We already have measurements in some favelas, such as Maré, which show that, within the favela, the temperature increases by 3% to 5% and, sometimes, up to 10% in some places, in relation to the surrounding neighborhood. This is because we have an occupation that has been developed in these decades and, at the same time, an urbanization that we call gray urbanization", he stated.
Unplanned urbanization and the reduction of green areas also increase risks related to climate events, such as floods and landslides. Among the most critical areas is the Serrana region of Rio, where municipalities such as Petrópolis, Teresópolis and Nova Friburgo are located.
The state of Rio de Janeiro has the largest area of favelas in the country at risk of landslides: 781 hectares. The problem is related to the lack of planning in urbanization and is aggravated by the reduction in green areas.
Experts argue that solutions to improve the environment in communities are developed with the direct participation of residents.
Initiatives to reduce these problems are already being developed in different communities. In Complexo do Alemão, in the North Zone of Rio, a partnership between the Raízes em Movimento Institute, the UFRJ School of Architecture, Rio City Hall and residents created a green urbanization project for the region.
After three years of research, the project received R$210 million from the federal government. The proposal is that interventions stop being isolated actions and become part of a public policy methodology that can be reproduced in other communities.
Among the planned measures are afforestation, implementation of orchards and creation of community gardens, with the possibility of generating income for residents.
“In this green urbanization, we have proposals and works that are already in the design, such as the afforestation of the main street, the creation of an orchard and the creation of community gardens, generating income for this population”, said Brum.
According to the sociologist, the participation of residents is one of the central points of the project.
“We are creating a methodology here that can be reapplied in any favela,” he stated.
