The Cerrado is irreplaceable for water distribution in Brazil. It works like an umbrella: as it has the highest soil, water is drained and distributed to 8 of the 12 important basins for water consumption and energy generation in the country. The lack of rain in the biome influences the drought in the Pantanal, in the São Francisco River and even in Itaipu, one of the country’s hydroelectric plants, supplied by the Paraná River basin.
Below, in this article, understand the following points:
- What is the influence of the Cerrado on the distribution of water in the country?
- What needs to happen to reverse the current scenario?
- Does any rain supply the country?
- Does preserving only the Cerrado solve the problem?
- Is the reason for the current water crisis global warming?
1. What is the influence of the Cerrado?
In the region of the Paraná River basin, which supplies Itaipu, the Cerrado accounts for almost 50% of all flow. The regions of São Francisco, Parnaíba and Paraguay – the latter linked to the Pantanal – have an even greater hydrological dependence: the biome is responsible for approximately 94%, 105% and 135%, respectively, of the entire flow.
Some of these indices are above 100% because they also include precipitation that reaches the ground but then evaporates due to the sun and geographic formations. These data are the result of research carried out by Jorge Werneck, from the Brazilian Agricultural Research Corporation (Embrapa) and director of the Regulatory Agency for Water, Energy and Basic Sanitation of the Federal District (Adasa).
That’s why, if it doesn’t rain in the Cerrado, the whole country feels it. The Pantanal is experiencing the worst drought in the last 50 years, and the exact reasons are still being investigated. But there is drought, and to solve it, it is necessary for rain in both biomes.
“In the summer of 2019 and 2020, it rained less than normal. This generated the fires in the Pantanal and the falls of the Paraguay River. Between 2020 and 2021, it should have rained almost 950 mm in the expected climatological total, and it has been raining less than 500 mm “, said José Marengo, climatologist, meteorologist and general coordinator of Research and Development at the National Center for Monitoring and Alerting of Natural Disasters (Cemaden).
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2. What needs to happen for the situation to improve?
According to the climatologist, the rain needs to reach the Cerrado and the affected regions. The Midwest is fundamental for water supply and, consequently, for cities, for agriculture and for energy generation. Raining is an urgent need to avoid further rationing.
“If you ask me: will the rain start in October at the right time? For now, at the moment, it’s too early to say.”
According to Marengo, the reservoirs have below average water. In the case of the Paraguay basin, the rates are even lower than last year. “If there is no rain in the Midwest, you will have less rain in the São Francisco River and also end up having less rain in the Paraguay River basin and in the Paraná River basin.”
Drought in Brazil — Photo: Fernanda Garrafiel/G1
3. Does any rain supply the country?
An overnight rain does not solve the problem in the Cerrado. It needs to rain with constancy and quantity. This is because the soil is already dry and needs to absorb some of the water that arrives initially.
“It’s that winter rain, which rains 2, 3, 4, 5 days in a row and in a good amount. (…) We need rain in the right places, at the right time, and with the right intensity and duration and frequency to promote the recharge of aquifers and the recovery of our rivers and reservoirs,” explains Werneck.
4. Does preserving only the Cerrado solve the problem?
No. Mercedes Bustamante, a professor at the University of Brasília (UnB) and one of the country’s leading experts on climate and Cerrado, says that resource management cannot see man-made boundaries. Amazon, Cerrado and Pantanal, and other biomes of Brazil, depend on each other.
“Natural resources do not have the borders that we place. When we talk about conservation, it is important for you to look at this connectivity”.
The Amazon, for example, when deforested, it can influence the Cerrado rain. Just like the Cerrado, if deforested, it hinders the cycle of rain and the water that arrives for energy production.
“The Cerrado has deep, very clayey soils, with good water drainage capacity, but it also depends on the vegetation cover. The vegetation forms a bridge between the atmosphere and the soil”, explains Bustamante.
The Amazon plays the role of, with flying rivers, contributing moisture to other regions of Brazil in Latin America. This forest water is received in part by the Cerrado, which follows its flow helping the Pantanal, the São Francisco River, the Paraná River basin.
“Part of the precipitation that there is in the Midwest is associated with the Amazon forest cover, with the transport of moisture that the forest makes, which in turn receives moisture from the oceans, then transfers it to the central portion in Brazil”.
Werneck makes it clear that it is possible to think of a management of natural resources that includes environmental preservation, food production, energy supply. According to him, it is a complex puzzle that needs to be designed in an integrated way with the greatest possible efficiency, an optimization of resources, with environmental wear within acceptable limits.
“It is possible to have water for the different sectors, but we need to evolve in planning and monitoring to have food and energy production, to have the industry developed and the cities supplied. Climate risks need to be considered so that we are prepared for these moments that will come. The moments of little rain and the moments of a lot of rain will happen.”
5. Is the reason for the current water crisis global warming?
For now, scientists assert with irrefutable certainty, according to the Intergovernmental Panel on Climate Change (IPCC), that the Earth is already living and will experience more and more extreme events. The lack of rain and excessive heat are part of the list of disasters foreseen for the coming years.
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“This year is a typical year of extremes. You’ve seen heat waves, colds, droughts, floods. Precisely, these extreme events, including the drought in the Pantanal, come in the same direction as global warming, it’s getting more and more intense. Global warming is a natural process, but the IPCC says that this natural process is being amplified by human activities”, says Marengo.
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The climatologist is researching, together with his work group, whether the lack of water and fire seen in the Pantanal in the last year could have happened without the action of man. According to him, it is a certainty that does not yet exist, despite the indications of the IPCC.
“What happened in 2020 was a combination. A summer drought and a heat wave in September and October. It affected the entire central region of South America, the Amazon of Peru, Paraguay, Bolivia, northern Argentina, he added. risk of fire. That’s what is now called compound extreme events. It’s not an event, it’s a combination of two or more events.”