Vulnerabilidade da Mesorregião Oriental do Tocantins a eventos de seca
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2023-11-10
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Universidade Estadual Paulista (Unesp)
Resumo
O agronegócio é crucial ao desenvolvimento econômico do país, e com a óbvia vulnerabilidade do setor, é imperativo analisar o impacto das mudanças climáticas, pois o suprimento hídrico é, em sua quase totalidade, oriundo das chuvas, e efeitos adversos sobre sua distribuição espacial/temporal são críticos. Secas severas e extremas impactam não apenas o agronegócio, mas a sociedade, o meio ambiente e a economia, e com uma abordagem multifatorial identificou-se as áreas de maior Vulnerabilidade de Seca Agrícola na Mesorregião Oriental do Tocantins, parte do MATOPIBA, que tornou-se um dos maiores polos de expansão agrícola nas últimas décadas. Utilizando indicadores geoambientais (Precipitação, Geomorfometria, Solos, Uso do Solo e Estado de Saúde da Vegetação), avaliou-se o grau de vulnerabilidade de seca no período 1989-2018 e os impactos sobre o agronegócio ali existente. A sazonalidade e as alterações do regime de distribuição de chuvas, a dinâmica do uso do solo e do estado de saúde da vegetação, reflexo destes dois primeiros indicadores, estão influenciando a vulnerabilidade de seca na MOT. O indicador de Precipitação mostra uma redução de 5,28% no volume de chuva anual (α = 0,05), na Estação Chuvosa (-4,54%) e na Estação Seca (-14,81%): em todos os meses do ano, o percentual médio de anomalias negativas de precipitação foi superior ao de positivas. O indicador de Geomorfometria revela que 4,15% da área apresenta Vulnerabilidade “Alta“/”Muito Alta“, enquanto o indicador de Solos indica que predominam as classes “Muito Alta”/”Alta” (72,61% da área). O indicador de Uso do Solo ressalta uma redução expressiva da vegetação nativa remanescente, convertida em pastagem e culturas agrícolas, e o indicador do Estado de Saúde da Vegetação aponta que todos os tipos (magnitude) de seca tornaram-se mais frequentes, notadamente na última década analisada. Os resultados realçam que os Índices de Vulnerabilidade de Seca “Alto”/”Muito Alto” atingem 25.018 imóveis (71,66% dos imóveis e 28,3% da área da MOT), impactando, em 2018, 3,4 milhões de hectares, ou 65,8% dos imóveis produtores de soja e 75,0% dos imóveis produtores de gado. Ficou comprovado o crescimento gradual da ocorrência de Secas Extremas, Severas e Total de Secas, e que as perspectivas de mudanças na Precipitação, no Uso do Solo e no Estado de Saúde da Vegetação devem se refletir no crescimento da Vulnerabilidade de Seca, com a possibilidade de impactar as safras agrícolas, a produtividade da pecuária e a redução da atividade fotossintética, o que pode afetar ou inviabilizar uma segunda safra, prática adotada em todo o país há muitos anos. Associados à falta de governança, traduzida pela incapacidade de reduzir o risco e de criar medidas de adaptação a estes eventos, há tendência de sérias consequências para os meios de subsistência (impacto social) e para a produção de larga escala (impacto econômico), para o ambiente e para as pessoas direta e indiretamente atingidas, pois as mudanças climáticas serão as principais ameaças sociais das próximas décadas, juntamente com as questões de degradação do solo e de conversão de áreas de vegetação remanescente para fins de produção de commodities.
Agribusiness is crucial to the country's economic development, and with the sector's obvious vulnerability, it is imperative to analyze the impact of climate change, as the water supply almost entirely comes from rain, and the adverse effects on its temporal/spatial distribution are critical. Severe and extreme droughts impact not only agribusiness, but society, the environment and the economy, and with a multifactorial approach, areas of greatest Vulnerability to Agricultural Drought were identified in the Eastern Mesoregion of Tocantins, part of MATOPIBA, which became is one of the biggest centers of agricultural expansion in recent decades. Using geoenvironmental indicators (Rainfall, Geomorphometry, Soil, Land Use and Vegetation Health Status), the degree of drought vulnerability was assessed in the period 1989-2018 and the impacts on the agribusiness there. Seasonality and changes in the rainfall distribution regime, the dynamics of land use and the health status of vegetation, a reflection of these first two indicators, are influencing drought vulnerability in the MOT. The Precipitation indicator shows a reduction of 5.28% in the volume of annual rain (α = 0.05), in the Rainy Season (-4.54%) and in the Dry Season (-14.81%): in all months of the year, the average percentage of negative precipitation anomalies was higher than that of positive ones. The Geomorphometry indicator reveals that 4.15% of the area presents “High”/”Very High” Vulnerability, while the Soil indicator indicates that the “Very High”/”High” classes predominate (72.61% of the area). The Land Use indicator highlights a significant reduction in remaining native vegetation, converted into pasture and agricultural crops, and the Vegetation Health Status indicator shows that all types (magnitude) of drought have become more frequent, notably in the last decade analyzed. The results highlight that the “High”/”Very High” Drought Vulnerability Index affect 25,018 properties (71.66% of properties and 28.3% of the MOT area), impacting, in 2018, 3.4 million hectares , or 65.8% of soybean-producing properties and 75.0% of livestock-producing properties. The gradual growth in the occurrence of Extreme, Severe and Total Droughts has been proven, and that the prospects for changes in Precipitation, Land Use and Vegetation Health Status should be reflected in the growth of Drought Vulnerability, with the possibility of impacting agricultural harvests, livestock productivity and the reduction of photosynthetic activity, which could affect or make a second harvest unfeasible, a practice adopted throughout the country for many years. Associated with the lack of governance, translated by the inability to reduce the risk and create adaptation measures to these events, there is a tendency to have serious consequences for the means of subsistence (social impact) and for large-scale production (economic impact), for the environment and for the people directly and indirectly affected, as climate change will be the main social threats in the coming decades, along with issues of soil degradation and the conversion of areas of remaining vegetation for commodity production purposes.
Agribusiness is crucial to the country's economic development, and with the sector's obvious vulnerability, it is imperative to analyze the impact of climate change, as the water supply almost entirely comes from rain, and the adverse effects on its temporal/spatial distribution are critical. Severe and extreme droughts impact not only agribusiness, but society, the environment and the economy, and with a multifactorial approach, areas of greatest Vulnerability to Agricultural Drought were identified in the Eastern Mesoregion of Tocantins, part of MATOPIBA, which became is one of the biggest centers of agricultural expansion in recent decades. Using geoenvironmental indicators (Rainfall, Geomorphometry, Soil, Land Use and Vegetation Health Status), the degree of drought vulnerability was assessed in the period 1989-2018 and the impacts on the agribusiness there. Seasonality and changes in the rainfall distribution regime, the dynamics of land use and the health status of vegetation, a reflection of these first two indicators, are influencing drought vulnerability in the MOT. The Precipitation indicator shows a reduction of 5.28% in the volume of annual rain (α = 0.05), in the Rainy Season (-4.54%) and in the Dry Season (-14.81%): in all months of the year, the average percentage of negative precipitation anomalies was higher than that of positive ones. The Geomorphometry indicator reveals that 4.15% of the area presents “High”/”Very High” Vulnerability, while the Soil indicator indicates that the “Very High”/”High” classes predominate (72.61% of the area). The Land Use indicator highlights a significant reduction in remaining native vegetation, converted into pasture and agricultural crops, and the Vegetation Health Status indicator shows that all types (magnitude) of drought have become more frequent, notably in the last decade analyzed. The results highlight that the “High”/”Very High” Drought Vulnerability Index affect 25,018 properties (71.66% of properties and 28.3% of the MOT area), impacting, in 2018, 3.4 million hectares , or 65.8% of soybean-producing properties and 75.0% of livestock-producing properties. The gradual growth in the occurrence of Extreme, Severe and Total Droughts has been proven, and that the prospects for changes in Precipitation, Land Use and Vegetation Health Status should be reflected in the growth of Drought Vulnerability, with the possibility of impacting agricultural harvests, livestock productivity and the reduction of photosynthetic activity, which could affect or make a second harvest unfeasible, a practice adopted throughout the country for many years. Associated with the lack of governance, translated by the inability to reduce the risk and create adaptation measures to these events, there is a tendency to have serious consequences for the means of subsistence (social impact) and for large-scale production (economic impact), for the environment and for the people directly and indirectly affected, as climate change will be the main social threats in the coming decades, along with issues of soil degradation and the conversion of areas of remaining vegetation for commodity production purposes.
Descrição
Palavras-chave
Agronegócio, Secas, Chuvas, Rain and rainfall, Droughts, Agribusiness
Como citar
KAZMIERCZAK, M.L. Vulnerabilidade da Mesorregião Oriental do Tocantins a eventos de secas. 2023. Tese de Doutorado. Universidade Estadual Paulista (UNESP), Instituto de Ciência e Tecnologia; Centro Nacional de Monitoramento e Alertas de Desastres Naturais (Cemaden). São José dos Campos: 2023. 260 p.