Anthropogenic forcing has impacted precipitation variability in the North China Monsoon Marginal Region
Description
Climate change has significant impacts on ecosystems and socioeconomic sustainable development globally or regionally. Moreover, the feedback mechanism between the coupling of anthropogenic with natural internal variability and climate change in Asian Summer Monsoon (ASM) region remains unclear. Here, we present a robust annual precipitation reconstruction for the period 1770-2020, based on the tree ring oxygen isotope data and the simple linear regression model in the North China Monsoon Marginal Region (NCMMR). Multisource proxy records detected widespread drought trends within the NCMMR since 1950s. The multiple linear regression (MLR) modelling and water vapor flux analysis from ensemble means of Community Earth System Model-Last Millennium Ensemble suggested that the precipitation variability in the NCMMR is strong influenced by the Indian Ocean Dipole, El Niño-Southern Oscillation, Atlantic Multidecadal Oscillation and Interdecadal Pacific Oscillation. Meanwhile, the ASM system changes are driven by internal variability, and regulate interannual precipitation. The fingerprint results based on the Coupled Model Intercomparison Project Phase 6 diagnostic revealed that the middle 20th century rise in anthropogenic aerosol emissions may have counteracted the influence of greenhouse gases, but the pronounced greenhouse gases forcing signal has been strongly detected since the early 21st century. The MLR has been widely used in climate change driver studies because of its reliability and accuracy, and fingerprint detection can qualitatively determine the influence of external forcing on climate change. Accordingly, the NCMMR precipitation reduction since 1950s is likely driven by the combination of anthropogenic factors and changes in the ASM caused by internal variability.