Global warming may turn ice-free areas of Maritime and Peninsular Antarctica into potential soil organic carbon sinks

The impact of intensified climate change driven by global warming on the stocks and dynamics of soil organic carbon in Antarctica is currently uncertain. Our objective with this was evaluate the potential repercussions of global warming on soil organic carbon under three Shared Socioeconomic Pathways. Employing a methodology that integrates soil field data, machine learning, and projections of future climate change scenarios for the Maritime and Peninsular Antarctic ice-free areas, we focus on predicting the soil organic carbon within the 0–30 cm soil layer. To achieve this, we utilized one of the largest soil databases of Antarctica, which contains data from 2800 observation sites. In our predictive modeling of SOC stocks, we used relief data and, bioclimatic variables (from Chelsa database) as predictor variables, primarily focusing on temperature, precipitation, and net primary production. The prediction performance of the soil organic carbon stocks model, as measured by concordance correlation coefficient, was 0.52 for the 0-5 cm soil depth, 0.56 for the 5-15 cm depth, and 0.46 for the 15-30 cm depth. Our model reveal that the effects of climate change, primarily changes in temperature and precipitation, are going to increase in soil organic carbon stock (359 ± 146 Mg to 686 ± 197 Mg), indicating that ice-free regions of Maritime and Peninsular Antarctica will tend to function as a carbon sink. However, the magnitude of the soil carbon sink is contingent upon the existing soil organic carbon content and soil depth. The estimated soil organic carbon stocks are controlled mainly by temperature and precipitation, which are interconnected with net primary productivity.