Regional effect as a probe of atmospheric carbon dioxide reduction in southern China

Abstract

To mitigate climate change, China is striving to reduce its carbon dioxide (CO2) emissions before 2030 and has derived a series of national environmental policies to advocate green development. Analysing the changes in regional atmospheric CO2 concentrations could be more convincing in evaluating the impact of the associated strategies. In this study, a three-year continuous observation campaign of the atmospheric CO2 mole fraction was first conducted at the summit of the Nanling Mountains, southern China in 2015–2017 to probe the timely feedback of the implementation of the green policies of the government. The effects of regional emissions and removals on the CO2 mole fraction were subsequently analysed to explore the primary processes and regional contributions driving the background CO2 concentration. Approximately 86.4% of the observed values were filtered as background events, with average CO2 concentrations of 395.9 ± 6.8 ppm. The curve-fitting CO2 mole fraction showed a slight short-term descending trend (0.6–2.2 p.m. y−1) that was rarely seen against the backdrop of a continuous rise of the global average over the years. In addition to the possible impacts of the changes in regional-scale CO2 sources and sinks, we inferred that the vigorously enforced sustainable development policies of the Chinese government should be accentuated to reduce CO2 emissions. Although the conclusion relies heavily on a relatively short dataset, this study may globally help the people to reduce carbon emissions.