1992-2015 Changes and Causes of Carbon Sink in Shenzhen City

Greenhouse gas emissions, including carbon emissions, are exacerbating climate change and may pose risks to the future survival of humans and other species on Earth. Therefore, measures to alleviate the pace of climate change have become increasingly urgent. Under this situation, carbon sinks have been put forward as one of the measures that can effectively reduce the amount of carbon emissions. Shenzhen, a city at the forefront of China’s Reform and Opening Policy, presents its carbon sinks change set as an example to China’s national Double Carbon Targets. Therefore, this study investigates the changes and causes of carbon sinks in Shenzhen city, a coastal city in southern China, between 1992 and 2015 using the land use area multiplied by its carbon density index retrieved from past scholarship. The QGIS software and the carbon density index method are used in this research. The QGIS software possess the advantages of being open source, suitable for city-wide scale investigations, and being able to visualise changes in land use/land cover (LULC). The carbon density index method simulated using InVEST model, based on past literature, is beneficial in terms of having high spatial resolution and suited for city-wide scale investigations. The results demonstrate that there has been an overall decrease of carbon sinks from 1.65*107 t in 1992 to 1.39*107 t in 2015 during the 23 years, with the main cause being urbanisation on cropland, the land use/land cover (LULC) with the highest carbon density index and the highest carbon sink in both 1992 and 2015 (8.20*106 t in 1992 and 5.53*106 t in 2015). Shenzhen has already implemented ecological compensation programmes such as constructing carbon capture, utilisation, and storage (CCUS) testing platforms, zero carbon emission office parks and schools, and more highly efficient electric charging power stations. In order to improve carbon sinks in Shenzhen, it is suggested that the government of Shenzhen could consider tailored strategies on different scales involving different stakeholders at long, middle, and short run, which may include restoring partial cropland or implementing land carbon sink technology in order to improve the carbon sink capacities of other LULC types.