Towards low-carbon cities through building-stock-level carbon emission analysis: a calculating and mapping method

Abstract

• A bottom-up method is proposed to calculate and map carbon emissions from urban building stock. • Building types and geometry are extracted to derive life cycle carbon emission inventories. • The calculation result is verified with a modified top-down method. • The method improves calculation accuracy and facilitates low-carbon urban planning. Building stock represents the primary source of urban carbon emissions. However, the amount and spatial distribution of building-stock-level carbon emissions remain unclear when formulating detailed carbon emission reduction goals for cities. In present study, a bottom-up method was established for calculating and mapping carbon emissions from urban building stock, which involves: (1) using inventory data to derive an aggregated reference model for calculating urban building carbon emissions and sinks with a building life cycle assessment model and a building archetype method; and (2) mapping and assessing carbon emissions from building stock to support low-carbon urban planning. The method was applied in Xi'an, China. The embodied carbon emissions from building stock in Xi'an were calculated as 4.13 million tCO 2 e·a –1 , the operational emissions as 20.45 million tCO 2 e·a –1 , building and natural carbon sinks as 0.067 million tCO 2 e·a –1 and 0.014 million tCO 2 e·a –1 , respectively. The method was validated with municipal statistical data for Xi'an. In addition, carbon emissions from urban building stock were mapped to identify carbon reduction hot spots. The proposed method allows municipalities to assess the environmental performance of urban building stock and urban planning schemes, thereby supports the sustainable development of cities.