Trade-driven black carbon climate forcing and environmental equality under China's west-east energy transmission

Abstract Given abundant energy and mineral resources in northwestern China, the west-east energy and mineral product transmission program play an increasingly important role in China's energy supply and consumption since the 2000s. Rapid growing energy and mineral products under this program might release increasing carbon emissions, causing climate and environmental consequences in northwestern China, which seems to be overlooked before. Here, a multiregional input-output analysis (MRIO) was conducted to investigate the temporal and spatial changes in black carbon (BC) emissions embodied in west-east energy and mineral product transmission from 2007 to 2012. Results were used to estimate BC's climate and environmental impact on China, focusing on northwestern China. The results show that BC emission flow patterns have been altered dramatically in China's domestic trade from 2007 through 2012. By 2012, 48%–77% of the consumption-based BC emissions from well-developed Beijing-Tianjin metropolises, East Coast, and South Coast regions were outsourced to other, primarily less-developed regions, of which northwestern China was the largest net BC emission outflow region at 48.8 Gg. The BC radiative forcing over China embodied in the west-east energy transmission was quantified using a compact Earth system model OSCAR. Model estimation shows that more than 30% of BC radiative forcing in northwestern China was related to the consumption from other regions across China. Central and eastern China were two significant contributors to the BC radiative forcing in northwestern China. Severe BC environmental inequality embodied in interprovincial trade was also identified in northwestern and central China provinces among 30 Chinese provinces. Inner Mongolia, Shaanxi, Ningxia, and Xinjiang in northwestern China experienced the most prominent climate and environmental losses via trade with well-developed provinces. These results provide references to alleviate trade-related pollution and climate impacts and to promote BC environmental equality in China.