Rating D (Falling Behind)
Brazil holds 12% of the planet’s freshwater reserves, making up 53% of water resources in South America. Bodies of water define a large part of the country’s borders – there are 83 border and cross-border rivers, in addition to hydrographic basins and aquifers. The transboundary river basins occupy 60% of the Brazilian territory.
The biome with the most significant area covered by water in Brazil is the Amazon, with an average area of over 10.6 million hectares, followed by the Atlantic Forest (over 2.1 million hectares) and the Pampas (1.8 million hectares). The Pantanal ranks fifth, with just over 1 million hectares of average area, behind the Cerrado (1.4 million hectares).
Research by MapBiomas (https://mapbiomas.org/superficie-de-agua-no-brasil-reduz-15-desde-o-inicio-dos-anos-90 ) indicates that the dynamics of land use based on the conversion of forest for livestock and agriculture and the construction of dams contribute to the reduction of water flow, based on the analysis of satellite images of the entire Brazilian territory between 1985 and 2020.
In all, the retraction of the surface covered with water in Brazil was 15.7% since the beginning of the 1990s, falling from almost 20 million hectares to 16.6 million hectares in 2020, indicating a reduction of 15.7% of the water surface in the country. The loss of 3.1 million hectares in 30 years is equivalent to one and a half times the water surface of the entire Northeast region in 2020.
The coordinator of MapBiomas Água, Carlos Souza Jr., comments that the result is quite worrying because the trend signal of water reduction in Brazil, with satellite data, is unmistakable. “Evidence from the field already indicates that people have already begun to feel the negative impact with the increase in fires, impact on food production and energy production, and even with water rationing in large urban centers,” alert.
According to the researcher, several factors can explain Brazil’s water surface reduction in the last 36 years. “The dynamics of land use based on the conversion of the forest for livestock and agriculture interferes with the increase in local temperature and often changes the headwaters of rivers and springs, which can also lead to the silting up of rivers and lakes. The construction of dams on farms for irrigation, troughs along rivers decrease water flow; and, on a larger scale, the large dams for energy production, with extensive water surfaces subject to evapotranspiration processes that lead to the loss of water into the atmosphere”, he says.
Reduction of rainfall
Pedro Côrtes, professor of the Graduate Program in Environmental Science at the Institute of Energy and Environment at USP, offers a broad explanation: the decrease in the annual volume of rainfall observed in recent years “is a consequence of the deforestation of the Amazon.” Therefore, “the reduction in rainfall is a trend that should continue for the next few years,” he says.
Depletion of water resources – a global problem
But the association between environmental damage and water resource reduction is far from an exclusive problem in Brazil. The most recent report by the IPCC (Intergovernmental Panel on Climate Change of the UN), released in August, is blunt. In the current situation, where the Earth is on average 1oC warmer compared to 1900 – a world where the climate results of human intervention did not exist – the chance of a drought occurring will be 1.7x greater in a decade. And the future may even become more worrying, projects the study.
- In a scenario where the planet warms up by an average of 0.5oC, severe and prolonged droughts tend to double in frequency within ten years. It is precisely on this path that everyone is now on if nations cannot significantly reduce greenhouse gas emissions before 2050.
Fonte: https://jornal.unesp.br/2021/10/18/crise-climatica-potencializa-falta-de-agua-no-brasil/
This Post was submitted by Climate Scorecard Brazil Country Manager Carlos Alexandre de Oliveira.