Deforestation, aggravating the historic floods in southern Brazil

The deforestation intended largely for crop of soy contributed to the severity of the floods devastating in the south of Brazilbecause native vegetation plays a key role in retaining the water, experts agree, who ask to reconstitute it.

In recent weeks, the state of Rio Grande do Sul has experienced an unprecedented climate disaster, with urban and rural areas devastated by rivers that overflowed due to large volumes of rain.

It was the fourth and worst extreme climate event that the region has experienced in less than a year, a phenomenon that scientists relate to warming, but also to the deforestation suffered in recent decades in the region.

“We have a global component of climate change, and a regional one, which is the loss of native vegetation. This increased the intensity of the floods“, says biologist Eduardo Vélez, from MapBiomas, a climate consortium of NGOs and Brazilian universities, to AFP.

Between 1985 and 2022, Rio Grande do Sul, an engine of the Brazilian economy thanks to its agricultural activity, lost 3.6 million hectares of native vegetation, a 22%according to a network study led by Vélez, the vegetation, mostly bushes, receded to the benefit of crop lands, especially soybeans, of which Brazil is the world’s leading producer and exporter.

Deforestation was also done to expand rice fields or forestry, based on the monoculture of trees such as pine and eucalyptus for economic exploitation, indicates the study published this month based on data collected by satellite.

Free way to water

This loss meant that with the intense rains the water flowed more freely, because the native foresta “ensures its infiltration into the soil” and prevents accumulation on the surface, says Jaqueline Sordi, a biologist and journalist specialized in climate change based in the region. In addition, the vegetation acts as a layer that protects the soil, preventing water from washing it away.

The brownish color of the water that affected the 90% of the municipalities of a territory the size of Ecuador, including its capital, Porto Alegre, “shows the extent to which tons and tons of soil were lost”explains Vélez.

This mud is now accumulating in the river beds, adding to the soil already deposited with the floods of recent times.

This, in turn, causes the channels to lose depth and, therefore, overflows occur more easily when it rains heavily. Like a fish that bites its tail.

Reforest

Recovering native vegetation is key to containing new floods, which will worsen and become more frequent with climate change, experts highlight.

“In addition to the measures to relocate the population” who lives in risk areas and “to rebuild the infrastructure, it is very important to have policies for the recomposition of native vegetation”according to Vélez.

The Escolhas Institute, specialized in sustainable development, calculated in a study last year that Rio Grande do Sul should reforest 1.16 million hectares “urgent” for the forest to perform its environmental functions.

For Vélez, there is currently no initiative “of weight” in that sense in Rio Grande do Sul, which in 2023 signed an agreement with other states in the south and southeast of Brazil to reforest 90,000 hectares of vegetation until 2026.

“Open the eyes”

At the federal level, the situation worsened under the government of former far-right president Jair Bolsonaro (2019-2022), a great ally of agribusiness interests and a skeptic of climate change, Sordi says.

In that period “Permits were made easier and Rio Grande do Sul benefited a lot from it. A kind of automatic authorization was created” of deforestation for crops, “without the need for independent studies” environmental, he explains.

A local councilor from Bolsonaro’s Liberal Party, Sandro Fantinel, sparked controversy last week by advocating cutting down trees “five meters on each side” of the main roads in the interior of the region, because – he maintained -, with the waterlogged roots and their weight, they caused landslides in those places.

For Sordi, disasters like the current one have the potential to “open the eyes” of society before science and its “signs”. “Sometimes you only pay attention when the problem arises”.

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