Interações entre desmatamento, mudanças climáticas e produção agrícola no cerrado e na Amazônia Brasileira

Abstract

Brazilian agricultural production is expected to continue to increase in response to the growing global demand for food and biofuels. However, agriculture is one of the sectors most susceptible to climatic variations. In this context, the devastation of the Amazon (AM) and Cerrado (CE) biomes raises concern because it contributes to the emission of greenhouse gases that intensify global climate change and synergistically interfere with the regional climate. Starting from this problem, this thesis investigates how regional climate changes (especially those associated with deforestation) can affect the productivity of soybeans, corn and pastures in these regions. In the first chapter we evaluated the loss of native vegetation and the reduction of precipitation in pixels of 28, 56, 112 and 224 km2 in the south of the Amazon region. The annual amount of rainfall has halved over the last 20 years in regions where agriculture occupied up to 60% of previously forested areas, which can cause a loss economic growth estimated at US$ 1 billion per year in the production of soy and meat in the region. Faced with these threats, agroclimatic risk management becomes increasingly fundamental. In this sense, in the second chapter we expand our investigation to the CE Biome and quantify the risk of regional climate change associated with deforestation during the soy and corn growing window. The risks of delays in the beginning of the rainy season, lower rainfall and warming are greater in more deforested regions. Added to the threats associated with global climate change, the number of regions and years in which dual-crop systems are cultivated at low risk is increasing. In the third chapter we estimate the losses in grain production recorded as a result of extreme weather and investigate their spatial determinants. Rainfall and temperature patterns show a tendency to change in both biomes, indicating that the climate is not within its normal variability. The drops in soybean and corn productivity have occurred more frequently and recently, causing Brazil to stop producing ≈23 million tons of grains and reflecting on the income of producers and the national economy. Losses reach 9% and 7% of Brazilian soy and corn production in the same period. Over the 13 years analyzed, AM producers lost more than US$ 8.5 billion, equivalent to ≈U$S 602.4 million/year due to crop failures. In the EC, losses resulted in a loss of US$ ≈23.8 billion or ≈U$S 1.7 billion/year. AM Deforestation generated losses of U$S 388.2 million (≈U$S 27.7 million per year), while deforestation in the CE generated losses of U$S 925.5 million (≈U$S 66.1 million/year). These results can guide actions focused on guaranteeing Brazilian grain production in a changing climate.