Emergy-based sustainability evaluation of China's marine eco-economic system during 2006–2015

China's sustainable development is inseparable from the sustainable development of marine eco-economic system. This paper applied emergy analysis to evaluate the sustainability of China's marine eco-economic system. The results showed that China's marine eco-economic system mainly depended on renewable resources to operate and renewable resources and economic output were the most important components. The gap between inputs and outputs was expanding in China's marine eco-economic system. The emergy density of China's marine eco-economic system was low. The unit emergy value of the southern areas were higher than that of the northern areas in China. The emergy yield ratio of China's marine eco-economic system increased steadily and the emergy yield ratio showed a pattern of high, medium and low coexistence. The environmental loading rate of China's marine eco-economic system was very low. The emergy sustainability index of China's marine eco-economic system was high, and the sustainability of the marine eco-economic system was good. In order to ensure the long-term sustainable development of China's marine eco-economic system, China should adopt a series of measures.