Reexamine China's terrestrial ecosystem carbon balance under land use-type and climate change

Land use and climate change can strongly affect the terrestrial ecosystem carbon balance. However, there is a lack of clarity for existing studies that investigate total carbon balance for China's terrestrial carbon balance (carbon storage and Net Ecosystem Productivity (NEP)). In this study, based on large data and the improved NEP model, we examined land use and climate change during 2000-2015 in China, calculated terrestrial ecosystem carbon storage change caused by land use change, and carbon sink/source variation under climate change; we found that during 2000-2015, 3.05 % of China's land area had land use type changes and caused 32.97 Tg of carbon storage loss, consisting of 10.4 Tg from vegetation carbon storage and 22.57 Tg from soil organic carbon (SOC) loss. Built-up land occupying ecological land was the most obvious land transfer type, especially for grassland degeneration. Both temperature and precipitation showed decreasing trends throughout China. Mean annual NEP showed a carbon sink value of 41.73 g C.m(-2).yr(-1), and the NEPs of carbon sinks were mostly distributed in South and Midland China and partly in Northeast China. There were obvious regional differences and the carbon balance showed that North China and Northwest China were regions of net carbon sources. The other four regions were net carbon sinks. Land use changes caused carbon storage loss in all regions, NEPs in North China and Northwest China were carbon sources, while in the other regions were carbon sinks. All NEPs exhibited an increasing trend during 2000-2015, except for Mid-South China. Finally, according to regional carbon balance characters, different policy implications were drawn which can serve for the formulation of territorial spatial planning. Land exploitation should be limited and environmental conservation is needed in North and Northwest China. The temperature in Southwest China has been increasing continuously and merits attention. The control of built-up land expansion in other regions should be strengthened.

Automated summary

Land use changes and climate change have significantly impacted the terrestrial ecosystem carbon balance in China. Research found that from 2000 to 2015, there were noticeable regional variations in carbon balance, with North and Northwest China acting as carbon sources while other regions were carbon sinks. Net Ecosystem Productivity (NEP) showed an increasing trend throughout the regions, except for the Mid-South region.