Integration of R Language and Century Model in the Mapping and Monitoring of Large-Scale Carbon Stocks

In Brazil, nearly 3/4 of greenhouse gas (GHG) emissions are associated with land use. The amount emitted in this sector has global relevance, since considering only 2020, the national emissions account for ~2.16 Gt.CO2e. Therefore, actions that promote the increase and maintenance of carbon stocks in areas of anthropic use contribute to mitigating GHG emissions. In this context, tools that enable the mapping and monitoring of C stocks on a large scale are essential. Process-based models are an excellent option for this task. The Century Model has been considered an important alternative, given its versatility in simulating the temporal dynamics of carbon in different land use and land cover systems. However, its large-scale application is a limiting factor, since it was developed for punctual simulations. In this context, we developed an application in R language that automates and optimizes the use of the Century model, enabling its use on a large scale by distributing and parallelizing the processing tasks according to the available computational infrastructure. We evaluated the performance of this application, simulating carbon stocks in Brazilian pastures over 36 years (1985 to 2020) based on a mapbiomas land use maps, with a spatial resolution of 1km2, totalizing ~1.5 million pixels. Using a computational infrastructure composed of 56 processing threads and 128 GB of RAM, the tool was able to complete the simulations in about 190 hours. As it is scalable according to the available computational infrastructure, this application is an important tool for mapping and monitoring carbon stocks associated with land use and land cover in large areas. Making it possible to evaluate on a large scale different management scenarios that can promote increased productivity and reduced GHG emissions from land use, which represents gains in economic and environmental terms. Ultimately, the use of this tool, available publicly and free (github.com/claudineisan/rcentury), can support the development of environmental policies necessary to comply with international agreements.