By: Altair Sales, interviewed by Elder Dias
The Brazilian Savannahs and the Fragility of the Cerrado
Professor Altair Sales tells journalist Elder Dias: “The protection of water resources is a matter of national security.”
Altair Sales sits for an extensive interview with Elder Dias of GGN on water management on a national level. His thesis is a radical one:
“The cerrado is extinct and this will lead to the end of rivers and reservoirs.”
I translate excerpts from the conversation.
One of the major authorities on the topic, the PUC Goiás professor says the destruction of the cerrado ecosystem is irreversible and that this undermines the supply of potable water nationwide.
Where the soil has been modified, the vegetation of the cerrado no longer grows. When the farmer or ranchers enrich this soil, improving its quality, this is good for other types of plant, but there is no way to restore it to its original condition, in terms of vegetation and soil.
The “Brazilian savannas” — the cerrado and caatinga — are a form of vegetation that assume diverse compositions throughout Brazil. They are zonal areas, like the Áfrican savannah, and correspond more or less to the Central High Plains [Planalto Central].
The Cerrado is the second largest ecosystem in Brazil, covering an area of 2,045,064 km² and covering 8 central Brazilian states: Minas Gerais, Goiás, Tocantins, Bahia, Maranhão, Mato Grosso, Mato Grosso do Sul, Piauí e o Distrito Federal.
Barbosa, professor at PUC Goiás, who believes the ecosystem of the «cerrado» has reached a tipping point in which downstream water management can no longer sustain demand because water management efforts do not take into consideration the shared resources that are the headwaters of the major tributaries
“… the most important factor in all this is that the waters that originate in the Cerrado feed the all the major basins of the South American continent. And it is from these headwaters that most of these basins are fed. These rivers arise from aquifers. When these aquifers reach the surface and form a water source, we call this a discharge area. How can a discharge be renewed? In areas of level ground, with rainwater, which is absorbed by the native vegetation of the cerrado.
Interesting to read as well the Professor’s explanation of the use of water by plant species typical of the Cerrado.
When you strip away the native vegetation of the prairie-like cerrado and replace it with another type of plant life, the ecosystem undergoes a change. The vegetation introduced — soy, or cotton, or any other grain production — has a very shallow root system and the water does not infiltrate as it should. In time, the level of the aquifers falls from year to year.
The native vegetation consists of plants that live with one third of their structure exposed, above ground, and two-thirds underground. This is a sign of an extremely complex radicular system [system of roots]. Thus when rain falls, this radicular system absorbs the water and feeds the phreatic sheet, which will feed the artesian wells, which function as aquifers. ”
“The extinction of the cerrado is a serious problem. Another, just as serious if not more so — according to you — is that in the near future we will have no water. Is the water crisis in Brazil a ticking time-bomb?
The extinction of the Cerrado also involves the major headwaters in Brazil, because the many if not all the principal hydrographic basins “sprout” from its waters.
The São Francisco River is a consequence of the Cerrado, for example: It is born in a Cerrado environment and is fed, on its left bank, by influxes from the Cerrado biome: Rio Preto, born in Formosa (GO); the Paracatu River (MG); The Carinhanha River, in western Bahia; and the Formoso river, born in Jalapão (TO) and flowing into the São Francisco.
If the Cerrado environment is degraded, there are no rivers to feed the São Francisco. You can count at least ten of these rivers disappearing every year.
How do you see the transposition of the São Francisco River?
It is much more of a political than a scientific activity. It answers to the political interests of major landholders of the Northeast in the ecosystems of the Caatinga, in the Norteast, and the Cerrado, in the Center-West.
The transposition is being built with two channels, one flowing north for 750 km and another flowing east for 600 km. The water is being absorbed by the dam in Sobradinho (BA), using a pump, to supply these channels, which are 10 meters deep and 25 meters wide. In realizing this project, the entire mechanism of the river is changed. Where once it flowed slowly, it now runs quickly because its waters are being absorbed. This accelerates the process of erosion and silt deposits.
As a result, this accelerates the death of the tributaries. To transpose the São Francisco is simply to establish a date for the death of the river, for its complete disappearance. It may well meet the economic needs of economic actors in the short haul, but in ten years it will all be gone.
Will it happen that quickly?
Yes, it is a matter of decades. Just look at the Meia Ponte River, in the Jaó Sector. Where once there was a lovely waterfall over an ancient weir, there is only a trickle. The current water level at Meia Ponte is the same as Botafogo Creek decades ago. It practically speaking no longer exists, except as a very rich water source for the Jardim Botânico, which it feeds.
Where the headquarters of Globo are located, in the Rio de Janeiro metro area.
But it only appears when the rains fill it rapidly. When that is not the case, it turns to a trickle.
Goiânia was also planned in terms of water resources. Bearing in mind the current situation, could we call the water crisis a hydrographic tragedy?
I would not say that Goiânia alone is in this situation. A broad policy was developed to occupy the center and interior of Brazil that motivated this disorderly occupation, ever since the Fundação Brasil Central and the Roncador–Xingu Expedition, after the construction of Goiânia and Brasília, the division of Mato Grosso and the creation of Tocantins state.
This is the fruit of dynamic capital that transforms reality. Rapid urbanization comes to the countryside, increasing the islands of high temperature and as a result, thanks to the introduction of pavement, preventing the rainwater from filtering down to feed the headwaters that gave life to the every same cities.
If things continue in this manner, we can foresee significant economic and social collapses in the Center-West. And not only there, but in the areas that branch out from there.
That adds up to Brazil as a whole, does it not?
Yes, including Amazônia. The Amazonas is fed by three vectors: the runoff from the Cordilheira dos Andes, an extremely irregular source, and the waters of the left bank, in particular the Solimões RiveThat adds up to Brazil as a whole, does it not?r, also an inconsistent source: two long periods of drought revealing sedimentation and sandy islands –- that area was until recently called the Óbidos Desert.
That is to say, the Amazonas is also fed by rivers originating in the Cerrado, such as Teles Pires (São Manuel), Xingu, Tapajós, Madeira, Araguaia, and Tocantins. These flow into the Amazonas near the river mouth, but contribute a large portion of its volume. So, then, we have the São Francisco, already drastically affected; the Amazonas, also affected; and the Paraná Basin, affected in much the same way as the São Francisco but probably with a very short life expectancy.
Will the process happen that quickly?
Once you start this process of degradation and drastic reduction of levels in the aquifer, this is irreversible. In some cases it takes several decades; in others, even less. We have classic cases of failed river transpositions that in some cases dried up entire seas. The Aral Sea, in Eastern Europe, has ships anchored in the salt. Its drainage system is endorheic and closed, with no outlet to the ocean. The Soviet Union, anxious to achieve self-sufficiency in the cotton market, transposed two rivers that fed the sea. Result: Resultado: within a decade, the cotton plantations were not producing, the sea dried up, and a large number of dust and salt storms affected 30 million persons, causing serious respiratory diseases, including cancer.
The same process is occurring with our rivers. The difference is that the process of occupation is relatively new to Brazil, starting in the 1970s, or 40 some odd years ago. That is, in less than half a century, an entire bioma was devastated. It has not disappeared completely because there is still some water left. But when this runs out, imagine the ensuing social unrest. In times of plenty, you can share a cup of water with your brother; but in times of scarcity, no one will share. This is part of our evolution as a species that is essentially egotistical. The Catholic church calls it “original sin,” but it really nothing more than selfishness, to take possession of certain assets and prevent others from using them. This has already led other peoples and races to extinction, and could lead to our extinction as well.
Until recently, we knew of two human species: the Neanderthal (Homo sapiens neanderthalensis) and ourselves (Homo sapiens sapiens). Today, we can speak of two humanities: a subdeveloped humanity trying to emerge from a pit of quicksand, and another, which swims in opulence. The question is whether we will some day come to classify humanity into two subspecies: the post-human and the sub-human.
Filed under: Brazil