Brazil depends on rainfalls that depend on forests – global issues


The monotony of soybean farming dominates the landscape in many regions of Mato Grosso and other Brazilian states. The regular rainfall in the Cerrado biome – the Brazilian savanna – favors this crop at the start of the rainy season, in September or October, and allows a second planting of corn or cotton before the dry season. Credit: Mario Osafa / IPS
  • By Mario Osafa (January)
  • Inter Press service

This country of continental proportions houses 12 percent of the world’s fresh water, but the drought that has exacerbated poverty in the semi-arid northeastern region and led to water rationing in a number of large cities in the past decade has shown that precipitation – partly generated by forestry systems. Distorted environmental – more important.

Desim, president of the Rural Union of Landowners in Taborah, a municipality in the northern state of Mato Grosso, said it was not just about quantity, it was also about timing: “It rains at the right time” is also the key to productivity. .

This is where the largest national production of soybeans, corn and cotton is concentrated in Brazil, the major producer and exporter of soybeans in the world.

The 64-year-old farmer, who immigrated from southern Brazil in 1986 and the rain thrived where “there was nothing” before, said the rainfall is not decreasing in that area. He told IPS by phone from his hometown that the reports of reduced rainfall “are just a hunch expressed by people who are not familiar with the situation.”

Dezem relied on his assertion on measurements he had made for more than 20 years, using a rain gauge that he admits is not completely accurate but shows variations from 1,600 to 1,800 mm in the agricultural year (September to September), with peaks of 1,500 and 2,500.

But the electricity sector, which also depends mainly on rainfall, as rivers provide two-thirds of the country’s electricity, is in a different state.

The National Electrical System Operator, which controls the sources that generate electricity, has warned that the water level is low in the reservoirs of the hydropower plant, especially in two major Brazilian regions, the Midwest and Southeast, due to low rainfall across the country.

The scarcity of water makes it imperative to revitalize fossil-fuel-fired thermal power plants, which generate more expensive electricity in addition to greenhouse gases.

Some urban areas are already facing difficulties in supplying water. São Paulo, with a population of 22 million, suffered from severe shortages from 2014 to 2016, followed by Brasilia (population three million) in 2017-2018, and Curitiba (population 3.7 million), where legalization measures have been in place since 2014. 2019, without any possibility. It will be filed this year.

“The severity and frequency of droughts have increased in all regions of Brazil since the first decade of the twenty-first century, except for the south,” said Anna Paula Konya, a country researcher. National Center for Monitoring Natural Disasters and Alerts (Cemaden), based on a study conducted with 13 colleagues, using data since 1961.

The southern region benefits from its greater proximity to Antarctica, due to cold fronts that bring rain. Kona told IPS from Sao Jose dos Campos, where Cimmaden is based, that the southern tip of Brazil, as well as the north, has rainfall throughout the year, without the dry season in other regions.

“The circulation of the atmosphere is the main mechanism of precipitation formation in south-central Brazil, with the cold fronts and the South Atlantic convergence region that produce precipitation during the summer,” said climate scientist Jose Marengo, another researcher from Semadan.

This convergence zone carries clouds from the Amazon rainforest in the northwest to the southeast, passing through the midwest, ensuring rainfall is also over the extensive agriculture of Mato Grosso, which mainly occupies part of the Serrado Savannah biome that also benefits from being surrounded by the jungle. To the north and southwest.

If this system stops working, rainfall can be reduced by up to half, as has happened in the Pantanal (on the central-western border of Brazil), which has suffered from horrific fires in the past two years.

“The dry season appears to be getting drier, hotter and longer, which delays the onset of rain and increases the risk of fires,” Marengo told IPS from Sao Jose dos Campos, in the southeastern state of Sao Paulo.

He stressed that “forests in general are a source of moisture for rain in their region and neighboring areas, in addition to protecting soil and rivers.”

He explained that the Amazon forest recycles an enormous amount of water, generates three-quarters of the local rain and “transports moisture, so-called flying rivers, to the La Plata Basin” and south-central Brazil.

The Atlantic Forest, a forested strip along the Brazilian coast hundreds of kilometers wide at some points, carries moisture from the inner ocean, especially in the south and southeast where the forest is more extensive. In the northeast, forests occupy few coastal areas, and it is the trade winds that carry ocean clouds inland.

“The destruction of the Atlantic forest on the coast has contributed to a warmer climate and reduced rainfall in the northeast,” Konya said. Most of the region – 61 percent – has a semi-arid climate, with rainfall of between 200 and 800 mm per year.

The researcher, a physicist with a PhD in meteorology, said that the Caatinga, the exclusive biome of the semi-arid region, with low, twisted vegetation with few leaves, also suffered significant degradation, resulting in reduced precipitation and higher temperatures. .

She said it was important to bear in mind that rising temperatures exacerbate water shortages by causing more water loss through evaporation and transpiration of plants. In other words, the drought is intensified by heat.

“Removing vegetation does not have a direct effect on climate, rather it takes time, and has a cumulative effect. Rather, it affects climate and climate change affects vegetation,” in a vicious circle explaining “local microclimate changes,” with the differences between neighborhoods increasing as residents observed Locals, note it.

She lamented: “Forests help maintain the hydrological cycle, produce more rain and contain local temperatures. The vegetation along the coast has been a mechanism to keep moisture inland, but it has become looser.”

This process is demonstrated in the differences between rainforests along the coast where the original vegetation remains and a transitional area with less rain and less abundant forests before reaching the semi-arid “Sertau”.

Kona said that the environmental damage is reflected in the progress of desertification in some areas, but semi-droughts and droughts are ultimately due to the circulation of the ocean and the atmosphere affected by the phenomena of the Atlantic and Pacific climate, such as El Niño and La Niña.

With mainly intermittent rivers and few permanent rivers, rainfall is vital in the semi-arid northeast. Rainwater harvesting in domestic cisterns and other means has become a huge small infrastructure in rural areas, mitigating the damage of the longest drought in the region, from 2012 to 2017.

In the soybean growing region of Mato Grosso, rainfall is an economic factor.

“It varies a lot. It rains a lot in one year, less in the following year, but the average stays the same. This year, for example, the rains are slightly delayed. It would have been possible to plant early on September 20, but the owner said Land Dzim.

Track the life cycle there is precipitation. From January 10 to February 25, harvest soybeans and plant corn at the same time, because “90 days of moisture are required for a full harvest” and in April the rainfall begins to decline, before the dry season from May to August.

Timely rains and flat lands, which lead to mechanization, are the prerequisites for large-scale production that has drawn farmers from the south into what is now Brazil’s breadbasket.

© Inter Press Service (2021) – All rights reservedOriginal source: Inter Press Service


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