Intensified risk to ecosystem productivity under climate change in the arid/humid transition zone in northern China

Assessing the climate change risk faced by the ecosystems in the arid/humid transition zone(AHTZ)in northern China holds scientific significance to climate change adaptation.We simulated the net primary productivity(NPP)for four representative concentration pathways(RCPs)using an improved Lund-Potsdam-Jena model.Then a method was established based on the NPP to identify the climate change risk level.From the midterm period(2041–2070)to the long-term period(2071–2099),the risks indicated by the negative anomaly and the downward trend of the NPP gradually extended and increased.The higher the scenario emissions,the more serious the risk.In particular,under the RCP8.5 scenario,during 2071–2099,the total risk area would be 81.85%,that of the high-risk area would reach 54.71%.In this high-risk area,the NPP anomaly would reach–96.00±46.95 gC·m-2·a-1,and the rate of change of the NPP would reach–3.56±3.40 gC·m-2·a-1.The eastern plain of the AHTZ and the eastern grasslands of Inner Mongolia are expected to become the main risk concentration areas.Our results indicated that the management of future climate change risks requires the consideration of the synergistic effects of warming and intensified drying on the ecosystem.