The graceful hilly landscape of the Cariri in the south of the Brazilian state of Ceará stretches for more than a hundred kilometers all along the Chapada do Araripe. The landscape is yellow, beige and white, as is the sunlight that burns down on it from August to February. From far off, the hills have white caps dotted with sprinklings of green. The valleys have been clear-cut and are the color of sand, the grass has withered. Only a few trees still have green leaves. The umbuzeiro – the tree that gives water – no higher than four or five meters with its projecting branches and a water reservoir of 1500 liters in its roots, still lends shade to humans and animals alike. Most other plants lost their leaves in the winter. Closely packed, growing into each other as if they had to hold each other up, they defy the heat. Their bark is white and loaded with thorns. This view is repetitive every year in Brazil’s sertão. The Tupi people gave this vegetation the name “Caatinga” – the white forest.
Semi-arid regions are just a step away from being deserts. They can be found on all continents as cold or hot semi-arid zones. They are characterized by the fact that in the majority of the months per year, the rate of vaporization exceeds that of precipitation. The dryness index is 0.5. The global climate change endangers these regions in particular, since the long-term absence of precipitation due to El Niño in the short moist phases can result in serious, irreversible consequences.
The semi-arid region in the northeast of Brazil, the so-called “drought polygon” encompasses 1,135 municipalities (20% of Brazil’s municipalities) from eight federal states in the northeast of Brazil: Alagoas, Bahia, Ceará, Paraiba, Pernambuco, Piaui, Rio Grande do Norte and Sergipe; parts of the northern Minas Gerais are included as well. More than 23.8 million people live in the sertão – its 980,130 square kilometers is about three times as large as Germany. It is the world’s most densely populated semi-arid region. Due to its persistent aridity, large amounts of the agriculturally usable areas could eventually disappear in the northeast of Brazil – at least this is the fear expressed by the UN based on a study by the Federal University of Minas Gerais from the year 2010. The state of Ceará would be the most strongly affected with a maximum loss of 79.6% of its agriculturally usable area.
The resilience of the semi-arid landscape was continuously interrupted by the deforestation of large parts of the original Caatinga since the 19th century. Today there are very few regions which have original vegetation. The long-term intensive usage of the soil, particularly for livestock breeding, has led to the first signs of desertification in some municipalities. The drought of 2012 to 2016 sped up this process. Most retention basins in the region contain only 10% of their possible water reserves.
More than 1.7 million agricultural businesses dominate the regional economy. Small family-run businesses comprise 89% of these. Their crop yields are 50% lower than Brazil’s national average. Most crops are for personal consumption. Corn and beans are the main produce – rice in years with a lot of rain. A small farmer manages 11 hectares in the sertão, on which he also raises cattle, dairy cows and sheep. Recent years have seen an increase in goats added to the mix. These animals are better able to withstand aridity, but their meat is also worth less on the market than that of sheep. One new development is the attempt to initiate so-called productive gardens. On the one hand, the farmers need less space for this; on the other, four harvests can be achieved per year by careful irrigation using several cultivated plants. A successful fruit and vegetable garden stabilizes income as well as the sustenance of the farmers. In the ideal case, it can become a steady source of revenue. The annual gross domestic product per capita in semi-arid Brazil is about 6,500 reais (1,900 euros) – 67% lower than the national average of 19,500 reais (5,735 euros).
During the last drought, many families only managed to survive because the federal government instigated assistance programs for the neediest. The “Bolsa Família”, one of the largest national assistance programs in the world, supports about 26% of the Brazilian population. Developed under the president of the Workers’ Party, Lula (Luiz Inácio Lula da Silva (2003–2010)), it reduced poverty in Brazil by 27%. In the sertão, 3.4 million families or approx. 17 million people benefit from this assistance. In Ceará, the poorest federal state, 5.8 million people or 68% of the total population receive this support. The annual money transfer of 517 million reais (152 million euros) considerably changed the life of the poor. The local economy, especially retail trade, created many new job opportunities due to increased demand – even some small industrial firms were founded. People there now structure their daily lives more thoughtfully, they regularly send their children to school, the motorcycle has replaced the donkey as an everyday means of transportation. Additional infrastructure programs have enabled a majority of the houses to be supplied with electricity; branches of universities can now offer courses in small regional centers. These measures make it easier for inhabitants of the northeast of Brazil to live with to the climatic fluctuations in this semi-arid habitat.
The dry season is a phenomenon that occurs every year in the northeast of Brazil. Depending on the region, there are annual dry phases of six to 11 months. In the rainy season, an average of 300 to 800 mm of precipitation falls with average yearly temperatures of 25 to 28 degrees. During this time it is normal for small rivers to dry up completely, for trees to lose their leaves and their bark to turn white, and for the upper layer of the ground to turn to dust. This is referred to as a drought only once these dry phases are prolonged over years. In the northeast of Brazil, there is more than a 60% likelihood that a dry phase will extend from one year to the next. The most extreme point of the last drought (2012 – 2016) in the northeast of Brazil was in 2016 – the average annual amount of precipitation was about 200 mm. As a comparison, the average in Germany that same year was about 700 mm.
The semi-arid regions in Brazil are composed of various areas with different geographical and topographical characteristics – they are not regions that feature only one homogeneous landscape. The semi-arid climate zone in Brazil is home to more than 5,000 types of plants. The Caatinga is a biome unique to Brazil alone – because of this biodiversity native to Brazil, the semi-arid area in the northeast is subdivided into different regions: agreste, Caatinga, Carrasco, Seridó Cariria-Vehlhos, Curimataú and the sertão. The two most important habitats are the agreste and the Caatinga. The tropical forests run along the coast; the agreste forms a buffer zone between the tropical zone and the semi-arid zone. Subtropical vegetation predominates in the agreste due to the more regular and higher average amounts of yearly precipitation. The forest is shaped by tall trees with big, hard, hydrated leaves in less dense growth, high levels of natural light and large-leaved ferns. The soil is dark and rich – a large portion of the corn, bean and rice yields for the sertão is produced in these fields.
In contrast, the Caatinga dominates all regions of the northeast and is dense bush country with very few large trees. The harsh woody shrubs have small, soft leaves, armored with thorns and grow very closely together. The landscape is also shaped by various types of cactuses. The multi-armed mandacaru extends straight into the sky at heights of up to eight meters. Smaller in growth and resembling the arms of an octopus, the xique-xique is armored with thousands of thorns and blankets the landscape’s rocky islands. The palmeira – a heart-shaped cactus with few thorns – can be found in groups at the edges of the scrubland. During the dry season, the vegetation uses the temperature fluctuations between day and night in order to obtain the necessary moisture. In the rainy season between February and April, the landscape flourishes and agricultural production can be very abundant. However, the annual water balance tends to be negative – more water evaporates than is added to the soil through precipitation.
John Maurits of Nassau, governor of Dutch Brazil (1624 – 1654) and admiral of the Dutch East India Company in Brazil, charged the two naturalists Guilherme Piso and Jorge Marcgrave to document the region’s wide variety of fauna and flora during his term of office (1637 – 1644) in Recife. His goal was to gain economic and medical benefits from the plants in the region. From 1637 to 1645, both researchers undertook several joint trips, mainly in the area of the present-day federal state of Pernambuco. They published their research results in two books: História Natural do Brasil (1648) and História Natural e Médica da India Ocidental (1658). On their journeys, the researchers were able to gather many types of plants and animals that are today endemic. They carried out the only complete recording of the flora found in the Caatinga and the agreste. It was not until the end of the 1990s that the Brazilian government began to systematically research the semi-arid area, its plant and animal world, as well as to investigate agricultural concepts for small farmers in the region.