Greenhouse gas fluxes resulting from land use and land cover changes in the Caatinga Biome: expansion of the field database and regional-scale modeling

Abstract

Brazil, as a signatory to global climate agreements, is committed to building and reporting its estimates of atmospheric Greenhouse Gas (GHG) emissions and removals. Along with the burning of fossil fuels, changes in land use and land cover are the main processes responsible for GHG emissions in Brazil. However, due to the size of our country and the difficulties of generating robust scientific data on the subject, data on emissions in the different biomes of Brazil are still limited, and this limitation is quite accentuated in the Caatinga Biome. For this reason, the team of this proposal, which includes research groups from institutions in Pernambuco (UFPE, UFRPE and IPA) and São Paulo (CENA-USP and INPE), has been working together on this topic for over a decade. From the 02-2009 Fapesp-Facepe Public Notice and the Casadinho CAPES Program, UFPE, UFRPE, INPE and Cena-USP established collaborative field research and modeling activities that remain active to this day. The results of these interactions during this period generated the main databases that supported the Fourth National Communication in the land use sector in the Caatinga Biome. Given the above, in the present proposal, the team intends to continue with the collaboration and its general objective is to consolidate the field databases and improve the methodological tools for modeling at a regional scale and evaluating the impacts of changes in land cover and use on GHG fluxes in the Caatinga Biome. In addition to expanding the availability of data on emissions of the main GHGs (CO2, CH4 and NO2), the present proposal goes further, by quantifying emissions in the permanent plots of long-term ecological studies, a project that has been monitoring the cycling for several years. biogeochemistry in dozens of plots distributed in the main types of soils and land cover and use in the semi-arid region of PE. In this way, the emission data generated in the present proposal will be associated with an entire detailed history of data from these sites that will contribute to a better understanding of the variables that control emissions in these ecosystems. Among these variables, one of the hypotheses to be tested is that Biological Nitrogen Fixation (BNF) plays a crucial role in increasing the removal of atmospheric CO2 and stock in soils and vegetation in the ecosystems of the Caatinga Biome (even more important than water availability). The proposal also has among its objectives the improvement of regional-scale emissions modeling tools that have been developed by the team over the last few years, such as the Biomass Estimation System (BEST) and the Carbon Balance Calculator (CABALA-C). This joint scientific effort will generate information and products of paramount importance for Brazil, as it will allow increasingly robust estimates of emissions resulting from changes in land cover and use in the Caatinga. With this, it is expected to subsidize public policies and business strategies and income generation around the carbon economy in this sector, which may be essential for the economic viability of sustainable agricultural activity in the Caatinga Biome. (AU)