[Impact of Climate Change and Human Activities on the Changes in Net Primary Ecosystem Productivity in Henan...

Against the backdrop of global climate change and the "dual carbon" goals， by integrating multi-source remote sensing data （MOD17A3 and ChinaLand30） and statistical models （Theil-Sen trend analysis， ridge regression residual decomposition， and Hurst index）， the spatio-temporal evolution patterns and driving mechanisms of the Net Ecosystem Productivity （NEP） in Henan Province from 2003 to 2023 were analyzed. The results showed that： ① The average annual growth of NEP in Henan Province was 8.59 g·（m²·a）^-1， and the proportion of carbon sink areas increased from 78.3% to 81.7%， but there was significant spatial heterogeneity. The areas with enhanced carbon sinks were concentrated in the Funiu Mountain ecological barrier （44.5%） and the plain farmland belt （37.2%）， while the Zhengzhou metropolitan area （1.6%） has become a hot spot of carbon sources due to the expansion of construction land. In 2019， the superposition of extreme climate and urbanization led to a sharp decline in NEP [-80.47 g·（m²·a）^-1]. ② The land/NEP transfer matrix indicated that the conversion of cultivated land to shrubs [152.91 g·（m²·a）^-1] and the transformation of wasteland into forest land [191.63 g·（m²·a）^-1] significantly increased the carbon sink， while the conversion of cultivated land to impervious surfaces [-102.36 g·（m²·a）^-1] caused carbon loss， highlighting the contradiction between ecological restoration and urbanization. ③ Climate change extended the vegetation growth period through warming [0.05-1.14 ℃·（10 a）^-1]， with a contribution rate of 91.83%. Human activities jointly increased the carbon sink through the return of farmland to forest and farmland intensification， with a contribution rate of 90.79%. The areas driven jointly by the two factors accounted for 78.73%， but the Zhengzhou metropolitan area was under the dual inhibition of "climate-human" factors due to the urban heat island effect. ④ The Hurst index （H） predicted that the carbon sink in 49.06% of the plain agricultural belt will continue to be enhanced （H>0.5）， and 45.49% of the ecologically fragile areas （such as the former course of the Yellow River） may degrade （H<0.5）； thus， differential ecological management is required. The above results provide scientific support for the formulation of policies to coordinate food security and ecological security in Henan Province. It is recommended to strengthen the ecological compensation mechanism in the Funiu Mountain area and promote the "agroforestry composite" model in the plain agricultural area to enhance the potential of sustainable carbon sinks.