From 2000 to 2009, researchers in Tianjin observed factors affecting carbon emission in three industries using a specific calculation method. They found that economic growth and certain energy factors increased carbon emission, while energy efficiency, structure, and economic setup helped reduce it. Among these, improving energy efficiency was crucial in cutting carbon emission. By breaking down energy intensity, they discovered that efficiency improvements played a big role in decreasing energy use. Particularly, the better energy services in the third industry made a significant impact on energy intensity reduction from 1999 to 2009.