An abrupt shift in gross primary productivity over Eastern China-Mongolia

Abstract The terrestrial ecosystem in East Asia exhibits significant variability in the gross primary productivity (GPP), especially in semi-arid regions that are vulnerable to climate change. This GPP variation significantly modulates the local carbon budget, but our understanding of this and the underlying mechanism is still lacking. Here, we examine the GPP variability in East Asia and its relationship with climate change over the last three decades. We identify an abrupt decrease in GPP over the Eastern China-Mongolia region around the year 2000. This is attributed to an abrupt decrease in precipitation associated with the phase shift of the Pacific decadal oscillation. Of the twelve offline land surface models, eight could simulate this abrupt response, while the others fail due to the combination of exaggerated CO 2 fertilization effect and underrated climate impact. For accurate prediction, it is necessary to improve the sensitivity of the GPP to changes in CO 2 concentrations and the climate system.