Research on the carbon profit and loss correlation mechanism of sponge city construction life cycle in urban built up areas

Abstract

Climate change and rapid urbanization have changed the urban eco-hydrological cycle. Understanding the carbon profit and loss correlation mechanism of sponge city construction life cycle helps identify the eco-environmental benefits. This study constructs a set of carbon accounting methods under the concept of sponge city, which mainly consists of basic database, carbon emission accounting, carbon neutralization, uncertainty and sensitivity analysis module. Taking a typical urban built-up area in Xi'an City as an example, the main sources of carbon emissions from sponge transformation projects are material production and construction, and the sponge transformation project created a carbon source of 95 kg CO₂/m² during the two phases. Carbon neutrality mainly includes building energy saving and green space carbon sequestration, and the latent capacity is 219.92 kg CO₂/m²·year in 50-year accounting period, besides, the static investment payback period for carbon emissions is about 25 years in environmental economics. Based on the Analytic Hierarchy Process (AHP) + Data Quality Indicator (DQI) method combined with Monte Carlo simulation (MCs), the relative standard deviation (RSD)=0.17 is a relatively reliable result. The most significant influence on the results is the electricity factor in the parameters sensitivity analysis.