The commitment, made by President Hu Jintao at the United Nations Climate Change Summit in September 2009, that China will reduce its carbon emission per unit GDP (carbon intensity) by a "notable margin" by 2020 compared with the 2005 levels, signals a qualitative change in China's policy on energy-saving and emission reduction.

China's 11th Five-Year Plan (2006-10) raised the goal of "energy intensity", requiring energy consumption per unit GDP to decline by 20 percent of the 2005 levels in a bid to deal with energy supply constraint and environment deterioration. Energy intensity is a measure of energy consumption efficiency per unit GDP of a country in a certain period. Energy saving, certainly, means emission reduction, which could mitigate the impact of energy consumption on the environment. While this policy mainly aims at maintaining stable and sustained energy supply to economic development, it is basically a problem about the quantity of energy consumption.

Carbon intensity is the ratio of greenhouse gas (GHG) emissions produced to per unit GDP. Although it is also influenced by energy efficiency, carbon intensity is mainly subjected to energy structure, so it is a problem about energy quality (the proportion of clean energy in energy structure).