What is drought?
Drought is a natural phenomenon that does not have a rigorous and universal definition. It can be understood as a rainfall deficiency for an extended period of time, resulting in water shortage with significant negative repercussions on ecosystems and socioeconomic activities. The concept depends on the climatic and hydrological characteristics of a specific region and on the type of impacts produced. In the Brazilian scenario, six months without any rainfall in the semi-arid, for instance, is considered a normal situation. But if this occurs in the South or in the Amazon, it would be catastrophic.
What are the main consequences of this phenomenon?
Drought is considered one of the main constraints that affect food safety and the survival of more than two billion people around the planet. Productive efficiency in the regions more susceptible to droughts depends on several measures to monitor and mitigate negative effects of this phenomenon, through the rational and sustainable use of water and edaphic resources, and biodiversity resources.
When did the first reports of droughts in Brazil start?
The first reports in the Northeastern region date from the late 16th century (1583/1585), when approximately 5,000 Indians were forced to flee the backlands due to hunger and were bailed out by the Portuguese. Since then, numerous droughts have been registered – the most severe ones in 1615, 1692/93, 1709/11, 1723/27, 1744/45, 1776/78, 1790/93, 1831, 1844/46, 1877/79.
It is estimated that every 100 years there are between 18 and 20 years with intense droughts. The 20th century was one of the most drastic, registering 27 years of drought, in which stands out the period 1903/1904, when it became part of the Budget of the Republic, i.e., a portion was used to infrastructure against droughts. In 1979/1984 occurred the most prolonged and the large drought in the Northeast history, with intense droughts in 1993, 1998, 2001 and the current that started in 2012.
What measures are being taken to mitigate drought effects?
In 1891, an article was included in the Brazilian Constitution, which ensures that the State should give assistance to areas affected by natural disasters, including drought. Measures to combat the effects of this phenomenon – construction of barrages, dikes, and wells,assistance to the population with food distribution, establishment of task forces, etc. – began in 1909, with the creation of the Inspectorate of Construction Works Against Droughts (Iocs), which was later named National Department of Construction Works Against Drought (DNOCS). Since then, several measures have been taken, in a way that even having recently occurred in the Northeast the most intense drought of the last 50 years, the effects on populations were largely minimized due to the existent public policies.
Has the drought ceased to be a problem that is exclusive to the Brazilian Northeast?
São Paulo, the largest city of the country (southeast region), is currently suffering from the worst drought in the last 80 years. In 2012, about 650 municipalities in Southern Brazil declared state of emergency due to drought – 142 municipalities in Paraná, 375 in Rio Grande do Sul and 133 in Santa Catarina. Although it has never been an exclusive phenomenon of the Northeast, these drought areas have apparently been expanding. According to some scholars, since 1950 drylands around the world have been expanding at an increase rate of almost 2% per decade, and Brazil is no exception. However, problems such as São Paulo is facing nowadays, especially regarding water supply, can be attributed not only to climate change, but also to urban swelling and insufficient water supply infrastructure.
What about the specificity of the phenomenon in the Northeast?
It is said that the great problem of the Semi-arid is drought. Nevertheless, in many places of the region we have up to annual rainfalls of 800 mm – amount that, in other world's semi-arid regions, allows a greater agricultural production and, consequently, less poverty.
It is understood then that the major problem of the Brazilian semi-arid region is not the quantity of rainfall, but how rains are distributed in time and space.
It is common, for instance, that a single quarter of the year concentrates 90% of the annual precipitation. Similarly, within a cycle of crops, the amount of rainfall would often be sufficient for a satisfactory harvest if well-distributed throughout the cycle. However, it is concentrated in only one or two rains, which end up not allowing for an appropriate production and harvest.
Is drought present throughout the Brazilian Northeast?
The frequent phenomenon of drought is restricted to the Northeastern semi-arid region, which consists of an area of 969,598.4 km2, comprising 1,133 municipalities of the states of Alagoas, Bahia, Ceará, Paraíba, Pernambuco, Piauí, Rio Grande do Norte and Sergipe, in addition to the North of Minas Gerais. In coastal areas, rainfall rates is much higher due to the moisture that comes from the ocean. The same wind could bring water to the backlands, since the northeastern semi-arid is not surrounded by mountain ranges that retain moist winds. However, the sea breeze is not strong enough to cause rainfalls in a region larger than the 100 km of coastlines.
Is it possible to take advantage of the groundwater in the region?
Most of the Semi-arid is located over a crystalline basement. The aquifers of these areas are characterized by discontinuous water storage. The water is in rock fissures where they form small reservoirs and, at the contact with the substrate, easily mineralize. That is, the waters become brackish or saline, and are practically only useful for animals thirst-quenching. In other words, in general, wells have little and low-quality water.
Is irrigation the solution to the Northeast?
In some semi-arid areas, even with low rainfall, one will find a very important irrigated agriculture that produces fruit for exports. The sub-middle course of the São Francisco river, at the border of the states of Bahia and Pernambuco, and the Açu Valley, in Rio Grande do Norte, are good examples of this successful agriculture. It so happens that this situation cannot be extended to all semi-arid areas. One could consider expanding irrigated areas in the region, but there are limitations regarding the soil and water availability that do not allow irrigation throughout the region. There are also studies that show that only 5% of the Semi-arid meets the minimum requirements for irrigation.
What is the difference between fighting and coping with drought?
The 1980s brought the understanding that it is not possible to "fight" or "confront" the drought. There was a change of perspective as the notion of "dealing with it" was deemed more appropriate. The understanding is that, while on the one hand the natural phenomenon has always occurred and will even be more intense, thus it can not be defeated; on the other hand, it is possible to develop proposals and try alternatives based on the idea that it is possible and imperative to cope with it.
Can droughts be predicted?
Experts state that even with all modern technology, nothing can assure a prediction with more than 90 days. However, historical records indicate that droughts are cyclical, with more intense phenomena every 13 years, approximately. Therefore, droughts can not be predicted with precision, but it is possible that governments and populations can be prepared to minimize effects.
What were the effects of the 2011/2013 drought?
As a result of this drought, considered the greatest of the last 50 years, there was great impact on crops in all Semi-arid areas – great part of herds was lost, especially cattle: not only by death, but the animals were sold for very low prices to other regions. There was also great loss of pastures, predatory use of plants of the Caatinga to feed animals, including many native species (in certain areas 30 to 40% of plants were used for animal feeding). The difference of the drought in question in relation to others of similar proportions was that no mass exodus of the population of certain areas, or even sacking of fairs and supermarkets was observed. There was also no deaths caused by hunger and thirst. Even if it is not a definitive solution to the problem, this is mainly due to supplementary income policies that exist today in the country.
Can we say that people are more prepared?
People who live in the Semi-arid already live with drought, and one way or another have ways to deal with its effects. Living under a condition of eight to ten months per year without rainfalls is common. It turns out that in a drought like this it is always hard to be prepared. The concern with storing water for human and animal consumption, growing more tolerant plants, deploying strategic reserves to feed the animals and having a provision of hay and silage are still incipient practices, but one can already see many areas doing this to minimize losses caused by droughts.
What about solutions to deal with droughts?
There is not a formula for everyone. Nevertheless, it is essential that access to drinking water must be guaranteed for human beings and animal and, in some cases, to agriculture. Moreover, is it necessary a piece of land with sufficient size and quality to the livelihood of farmers and their families. Having policies to guarantee this and understanding that to live in this environment people need diversified production systems with food crops to generate some income, mainly in small farming, we must work with more resistant plants (using even native species), more rustic animals, even if they are less productive, and aim at harmony with the environment. Another crucial issue for coexistence is an effective technical assistance and rural extension.