Regional Assessment of Climate Potential Productivity of Terrestrial Ecosystems and Its Responses to Climate Change Over China From 1980-2018

Evaluating the potential productivity of the terrestrial ecosystem is extremely important to ascertain the threshold of vegetation productivity, to maximize the utilization of regional climate resources, carbon sequestration and to mitigate climate warming caused by rising CO
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concentrations. However, most previous studies neglected the optimum state of natural vegetation without human intervention and regional change trend of vegetation under future climate change. In this study, variations in spatio-temporal distributions of climate potential productivity (CPP) over China from 1980 to 2018 are analyzed with the synthetic estimating model. A comprehensive regionalization method (Principal components analysis, PCA) based on standardized precipitation evapotranspiration index (SPEI), and statistical analysis methods are adopted to assess CPP and its response to the climate change in different regions of China. The results demonstrate that the global temperature rising and precipitation decreasing have obvious effects on the productivity of terrestrial ecosystem and its spatio-temporal distribution in different sub-regions and ecosystems. Among them, precipitation is the dominant factor, and temperature significantly affects some regions such as Tibetan Plateau (TP) and Northeast China (NE) with high-altitude or high-latitude. The optimum temperature for the CPP in Xinjiang (XJ) region and Northwest China (NW) is 7.5°C and 8°C, respectively. With regards to the ecosystems, the CPP of grassland shows complex trends in XJ, Southwest China (SW), NE, and TP; especially in XJ (NE), the CPP shows a decreasing (an increasing) trend when the temperature is more than 7.5°C (0°C). Linear correlations occur between farmland CPP and temperature in each sub-region except for XJ. The same situation also exists at forest CPP, especially in TP, NE and NC regions. However, under the temperature increasing and precipitation decreasing, there are slight adverse impacts on the CPP of vegetation at the national scale, indicating that drier and warmer climate are detrimental for vegetation growth.