Mariculture carbon sequestration efficiency in China: Its measurement and socio-economic factor analysis

The main characteristic of mariculture carbon sequestration is the high carbon storage and flux with minor negative impact on eco-environment. It may be an efficient way to net-zero carbon emissions (carbon neutrality) and sustainable development due to the combination of environmental and economic values. Therefore, this paper defines Mariculture Carbon Sequestration Efficiency (MCSE) as the carbon sequestration effect and economic effect in mariculture based on a certain input. First of all, this paper measures China's MCSE based on a series of data from 9 coastal provincial-level regions during 2013-2020 by Super-SBM model. Next, this paper explores the socio-economic factors of China's MCSE by STIRPAT model. Finally, this paper summarizes the advantages of China's mariculture carbon sequestration. It can be concluded from the results that China's 9 coastal provincial-level regions shows an approximate upward trend during 2013-2020, and similar trends are more obvious in the Circum-Bohai Sea (CBS) and Pan-Pearl River Delta (PPRD) Economic Zone. In 2020, 6 in 9 regions in the sample are efficient on technical efficiency (efficiency measured with constant returns to scale), and all regions in the sample are efficient on pure technical efficiency (efficiency measured with variable returns to scale). The MCSE in the PPRD Economic Zone such as Guangdong has the highest level. Shandong also has a high level of MCSE because of the high economic outputs in mariculture. The main drawback in the Yangtze River Delta (YRD) Economic Zone and Hebei province is that the scale efficiency is not very high. Jiangsu is hampered by the low efficiency of energy utilization. The analysis of socio-economic factors based on ridge regression model and panel regression model presents that the level of population and service industry produce positive impacts on China's MCSE, whereas the level of affluence and energy intensity produce negative impacts on China's MCSE. Some policy implications, such as developing the advantages of the featured mariculture in scale, exploring new growth drivers for developing mariculture carbon sequestration, developing a market economy of mariculture carbon sequestration, and forming a sustainable modes of mariculture carbon sequestration, are proposed.