Spatial-temporal differentiation of carbon efficiency and coupling coordination degree of Chinese county territory and obstacles analysis

Carbon efficiency (CE) and coordination of productive-living-ecological (PLE) functions are two criteria often used to assess low-carbon and sustainable development status. Previous research lacked attention on county level in PLE perspective. The study established carbon efficiency evaluation index system from PLE dimensions used grey correlation analysis to calculate carbon efficiency index (CEI) and coupling coordination degree (CCD) of 4 typical counties: Changxing, Qingcheng, Jintang and Wu'an. The study proposed an obstacle classification to screen out not only obstacles led to CE decrease, but also potential ones caused sensitive changes of CE. The results showed that: 4 counties all stayed in bad condition of CE. CEI and CCD of Qingcheng was highest followed by Jintang, Wu'an, and Changxing was lowest. From 2012, CEI and CCD of Changxing began to decline with fluctuation. The other three had rising tendency with different gradients. PLE efficiencies were all unbalanced with characteristic that productive efficiency was low while high in living efficiency or ecological efficiency correspondingly. Indicators represented development level and construction situation, like urbanization rate, growth rate of GDP and road density also played role of obstacles in study counties. Water consumption, SO2 emission reduction and sewage processing had obvious effect on CE changes.