The study investigates the contribution of semi-arid ecosystems to interannual variability in the global carbon cycle, focusing on the 2011 record land carbon sink. Using a terrestrial biogeochemical model (LPJ DGVM), atmospheric inversion (MACC-II), and global carbon budget accounting methods, the researchers found that the 2011 land carbon sink was driven by increased carbon uptake in semi-arid regions, particularly Australia, due to higher precipitation during the 2010/2011 La Niña period. The study highlights the importance of semi-arid ecosystems in global carbon cycling and suggests that tropical rainforests may become less significant in the future. The findings also indicate that the enhanced carbon sequestration in wet years may be transient, as rapid decomposition or fire could release carbon back into the atmosphere. The research underscores the need for further studies to understand the dynamics of semi-arid systems and their potential impact on global carbon budgets.The study investigates the contribution of semi-arid ecosystems to interannual variability in the global carbon cycle, focusing on the 2011 record land carbon sink. Using a terrestrial biogeochemical model (LPJ DGVM), atmospheric inversion (MACC-II), and global carbon budget accounting methods, the researchers found that the 2011 land carbon sink was driven by increased carbon uptake in semi-arid regions, particularly Australia, due to higher precipitation during the 2010/2011 La Niña period. The study highlights the importance of semi-arid ecosystems in global carbon cycling and suggests that tropical rainforests may become less significant in the future. The findings also indicate that the enhanced carbon sequestration in wet years may be transient, as rapid decomposition or fire could release carbon back into the atmosphere. The research underscores the need for further studies to understand the dynamics of semi-arid systems and their potential impact on global carbon budgets.