碳普惠制下市民乘坐地铁出行减碳量核算方法研究——以广州为例

碳普惠制是一种以城市居民为主体的温室气体自愿减排机制。将乘坐地铁出行作为低碳行为纳入碳普惠制，是建设全民参与型低碳社会的重要探索。本文提出了替代法和均值法两种市民乘坐地铁出行减碳量的核算方法，并以广州市为例，计算了2015年广州市民乘坐地铁出行的减碳量。结果显示：替代法下广州市民乘坐地铁出行的减碳量约为0.5419 kg CO₂/人次，均值法下约为0.5155 kg CO₂/人次，如果按2015年广州市地铁系统的客运量计算，替代法和均值法下全市地铁系统的年减碳量分别约为130万t CO₂和124万t CO₂。其中，替代法主要参考已有的CCER方法学设计，具有一定的理论基础，但其替代出行模式的确定受被调查对象的主观影响较大，而均值法以城市现有的机动化出行模式为基准线，较少受到人为因素的干扰，均值法被认为更适合于计算碳普惠制下市民乘坐地铁出行的碳减排量。

Study on Carbon Emission Reduction Calculation of Subway Travel-Take Guangzhou as an Example

Carbon Generalized System of Preferences (carbon GSP) is one kind of Voluntary GHG Emission Reduction Mechanisms, which take residents as the main objects. It is an important exploration for taking subway travel as a low-carbon behavior into carbon GSP to build a low carbon society. This paper proposes two different carbon emission reduction calculation methods of subway travel, based on CCER methodology “Mass Rapid Transit Projects”, combined with the availability of traffic data and the purpose of carbon GSP. Carbon emission reductions of Guangzhou subway travel in 2015, as an example, were calculated by using these two methods. Under substitution method, the carbon emission reductions of Guangzhou subway travel were about 0.5419 kg CO₂ per person, but under averaging method, this value was about 0.5155 kg CO₂ per person. According to the passenger traffic of Guangzhou subway in 2015, the annual carbon emission reductions of Guangzhou subway system were about 1.30 million t CO₂ under substitution method and 1.24 million t CO₂ under averaging method, respectively. In these two methods, substitution method is designed based on the existing CCER methodology, which has theoretical basis. But in the actual calculation process, the setting of alternative travel patterns will greatly rely on the subjectivity of survey objects. In contrast, the baseline of averaging method is the current urban motorized travel patterns, less subjected to human disturbance. By contrast, the averaging method is more suitable for calculating subway travel carbon emission reductions of carbon GSP.