Dinâmica do uso e cobertura da terra e seus efeitos para os estoques de carbono da Mata Atlântica sergipana

Abstract

The forest ecosystems of the Atlantic Forest biome and their ecosystem services directly benefit 70% of the Brazilian population living in this biome and indirectly benefit all human societies. The fragments of this biome found in the state of Sergipe, Brazil, are suffering from intense deforestation, which is contributing to worsening climate change and socio-environmental and economic problems. A better understanding of the native forest areas of the Atlantic Rainforest in Sergipe, as well as CO2 valuation, can help environmental policies to reduce deforestation. This study aimed to analyze the forest fragmentation of Sergipe's Atlantic Forest in the years 2001 and 2021 and the dynamics of land use and land cover for the years 1985, 2001, 2011, and 2021; simulate land use and land cover for the years 2031 and 2051, assuming the current Business as Usual (BAU) trends as the reference scenario; quantify and value carbon stocks for the year 2021 and the BAU scenarios for the years 2031 and 2051; analyze trends in the implementation of projects in the Atlantic Forest in the context of the voluntary carbon market. The results showed that, between 1985 and 2021, the forest formation (FF) and mangrove (MA) classes showed an increase in the forest cover of large fragments and the connectivity of fragments in the Sergipe Atlantic Forest. However, the agriculture-pasture mosaic class (areas of agricultural use where it was not possible to distinguish between pasture and agriculture) saw the greatest percentage (5.27%) and net (around 514.00 km2) increase among the land use and cover classes assessed in the study area. In addition, the coverage of native vegetation classes was reduced by 2.45% (around 239.00 km2). The estimated carbon stocks for the area totaled 19,523,204.09 Mg of C in 2021, and 18,385,262.02 Mg of C and 18,830,389.63 Mg of C in the BAU scenarios for 2031 and 2051, respectively. Thus, in the BAU scenarios, total emissions reached 1,137,942.07 Mg CO2 in 2031 and 692,815.16 Mg CO2 in 2051, imposing an opportunity cost for society of US$ 30.75 million and US$ 18.71 million, respectively, considering the value of social carbon. The study also showed that, currently, 72% of the projects developed in the Atlantic Forest are in the category of Afforestation, Reforestation, and Revegetation (ARR), demonstrating the biome's strong aptitude for restoration activities. However, the certification processes in the carbon market still have several weaknesses and need to be improved to achieve their objectives effectively.