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Dryland ecosystems cover approximately 40% of terrestrial land surfaces and form a major component of global biogeochemical cycles, which are sensitive and vulnerable to climate change. Rapid climate change observably threatens vegetation growth and profoundly affects the global carbon cycle. However, interannual variations in vegetation growth, and changes in coupling between vegetation growth and precipitation in response to drought are not fully understood in the dryland ecosystems of the Silk Road Economic Belt (SREB). By combining remote sensing normalized vegetation indexes from GIMMS (GIMMS NDVI), simulated net primary productivity levels from TRENDYv2 (TRENDY NPP), terrestrial water storage change data (△TWS) derived from GRACE, and climate grid datasets, we investigated climate change, vegetation growth and nonlinear changes in coupling between vegetation growth and precipitation in the pregrowing and current seasons during 1982-2015. The results show intensified drought and extensive vegetation browning in all seasons, especially the summer, across the drylands of the SREB from 1993 to 2015. Precipitation in the pregrowing season significantly contributed to vegetation growth in the subsequent spring and summer, showing that the effects of precipitation in the pregrowing season on subsequent vegetation growth lags by almost two seasons. We also found that intensified drought significantly strengthened the coupling between vegetation growth and precipitation in the pregrowing and current seasons. These results highlight the nonlinear response of vegetation growth to intensified drought, and can be referenced to improve the coupling of land-atmospheric models for drylands. Plain Language Summary Latest studies have reported a substantial terrestrial drying trend for the 21st century. And the relationship of intensified drought and vegetation growth has been widely studied. A well-known conclusion is that on the spatial gradient, as the drought intensifies, the vegetation is more dependent on precipitation. However, on the temporal scale, as the drought intensifies, the nonlinear changes in the relationship between vegetation growth and precipitation are rarely studied, especially in arid regions. In this paper we investigated climate change, vegetation growth and nonlinear changes in coupling between vegetation growth and precipitation in pre-growing and current seasons over drylands of the Silk Road Economic Belt (SREB) during 1982-2015. Our results demonstrate that intensified drought and extensive vegetation browning across drylands of the SREB from 1993 to 2015, and precipitation in the pre-growing season significant contributed to vegetation growth in the subsequent spring and summer, showing that the effects last by almost 2 seasons. We also find a significant strengthening of coupling between vegetation growth and precipitation in pre-growing and current seasons due to intensified drought. These results highlight the nonlinear response of vegetation growth to intensified drought and can be referenc...

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