Abstract:
Annual net greenhouse gas emissions, which measure the degree of carbon neutrality of a catchment, are the sum of the carbon dioxide (CO
2) equivalent of net emissions of CO
2, methane, nitrous oxide and other greenhouse gases, of which the magnitude of ne tO
2 emissions indicates the catchmen tarbon balance. Therefore, in order to achieve China's ambitious goal of peaking carbon emissions by 2030 and become "carbon neutral" by 2060 (the "double carbon" goal), it is important to have a comprehensive understanding of the carbon balance of each catchment. This paper estimates the carbon balance of Jinjing River Catchment in Changsha County, Hunan Province, based on survey data, MODIS datasets and previous studies, and using the reference method provided by the Intergovernmental Panel on Climate Change (IPCC) Greenhouse Gas Inventory Guidelines. The results showed that total annual carbon sequestration (in terms of pure carbon) in the catchment ranged from 12.89 thousand to 19.82 thousand t/a from 2011 to 2020, with forest, tea paddy and paddy field ecosystems carbon uptake accounting for 83.4%, 2.6%, and 14.0% of the total uptake, respectively. The total carbon emissions in the catchment range from 3.73 thousand to 13.42 thousand t/a with the main emission contributors being transportation and industrial production, which account for 57.1% and 28.8% of the total carbon emission from 2011 to 2020, respectively. The carbon balance index of the Jinjing River Catchment was less than 1, indicating that the catchment is an atmospheric carbon sink. This study provides a typical case for the inventory of carbon sources and sinks at the catchment scale, and provides a useful reference for the study area in formulating the implementation path of the "dual carbon" target.