Between 1985 and 2020, urbanized areas in the country doubled, from 2.1 million hectares to 4.1 million hectares. Urban expansion in Brazil has been advancing rapidly: an annual rate of 1.97%, higher than the population growth rate of 1.45%. These data are part of the survey on urbanized areas based on satellite images captured between 1985 and 2020, which MapBiomas released on Friday, October 5th, on its YouTube channel. 

Led by São Paulo, with 218,985 hectares, the 20 largest population centers in the country concentrate 30% of urbanized areas. Rio de Janeiro (174,534 ha), Brasília (89,243 ha), Belo Horizonte (87,121 ha), and Curitiba (74,239 ha) complete the top five in area.  

Throughout the country, informal areas have grown by the equivalent of 95 thousand soccer fields between 1985 and 2020. This growth is equivalent to three times the area of Salvador or eleven times the area of Lisbon, Portugal. In total, 4.66% of the growth in urbanized areas between 1985 and 2020 has informal characteristics. The temporal analysis of informally occupied areas throughout the country shows that they are more sensitive to economic and social policies, growing more during periods of GDP contraction.

The Amazon leads the percentage of growth in informal settlements in the territory: 18.2% of urban growth in this biome occurred in informal areas. The states within this biome also lead when the total area is analyzed. In the state of Amazonas, informality accounts for 45% of urbanized areas; in Amapá, 22%; in Pará, 14%; and in Acre, 12.6%. Only Espírito Santo, with 21.5%, has a higher participation of informality in the total urbanized area of its territory than the states of the Amazon. 

When analyzing how much of the total urbanized area is informally occupied, Manaus, Belém, and Salvador stand out. In the two major capitals of the northern region, informality has been the norm over the past 36 years, as in both cases, the percentages remain above 50%. Belém has 51% of its urbanized area occupied by informality, while in Manaus, this percentage is 48%. When we include the boundaries of the Special Zones of Social Interest (ZEIS) defined in the city's master plan, Salvador approaches this pattern, with 42%.

Satellite images also allowed the identification of occupations in areas with slopes greater than 30%, which are more prone to landslides. They are predominantly located in Minas Gerais, Rio de Janeiro, Santa Catarina, Espírito Santo, and São Paulo. However, they are already starting to occur in Amazonas, Paraná, Rio Grande do Sul, Alagoas, Pernambuco, and Bahia. In total, the growth of urban occupation in areas with high slope was around 40 thousand hectares – meaning, 1 in every 100 hectares is already in high-risk areas due to slope. 

"A combination of these two data sets should raise a yellow flag for public managers because they create perfect conditions for urban disasters," explains Julio Cesar Pedrassoli, one of the coordinators of urban infrastructure mapping at MapBiomas. "On one hand, we have large areas without adequate public services; on the other hand, the risk of accidents is compounded by the increasing occurrence of extreme weather events. Looking at informal settlements from the angle of adaptation to climate change is essential to avoid tragedies," he warns. 

Although the Atlantic Forest still concentrates more than half of Brazil's urbanized areas (54.7%), the highest growth recorded in the last three decades occurred in the Amazon, Caatinga, and Cerrado – all with annual growth rates exceeding the national average: 2.5% per year, 2.53% per year, and 2.08% per year, respectively.  

The survey showed that of the urbanized areas in 2020, just over one-third (34%) were pasture areas and areas of mixed agriculture and pasture, and 13% were native vegetation in 1985. The areas used for urban expansion reflect the predominant land use in each region. In the Northern region, for example, 32% of the advancement occurred on native vegetation - almost three times the national average. In the South, nearly 10% of the urbanized areas in 2020 were dedicated to agriculture in 1985, while in the Brazilian average, this percentage is only 4%." 

The Cerrado, which already holds one-fifth of the country's urbanized areas, was the biome that lost the most native vegetation to urban expansion. Of the over 388 thousand hectares of native vegetation converted to urban areas year-on-year, 33% (127 thousand hectares) were in the Cerrado. In second place is the Amazon (almost 92 thousand hectares). In terms of percentages, the biome that lost the most forests was the Atlantic Forest: 58.3% of the native vegetation converted to urban areas in this biome were forests. In the Amazon, this percentage was 44.1%. 

Aglomerados Subnormais are urban areas occupied for residential use in locations without land ownership by the occupants. They have irregular urban patterns, lack essential public services (such as water, sewage, and regular garbage collection), and are sometimes located in areas with restrictions on occupation (such as areas at risk of landslides, floods, or flooding). Official definition at: https://www.ibge.gov.br/geociencias/organizacao-do-territorio/tipologias-do-territorio/15788-aglomerados-subnormais.html?=&t=o-que-e 

The Special Zones of Social Interest (ZEIS) or Areas of Special Social Interest (AEIS) are urban planning instruments that define areas of the city intended for the construction of affordable housing: https://www.capacidades.gov.br/dicionario/index/letra/z

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