China emits far less than thought

Contributing more than 26 percent of the world's total CO2 emissions, China does not appear to hold any advantage in climate change negotiations.

However, new scientific evidence published by UK-based scientific journal Nature shows a different picture: emissions from China only contribute 10 percent to global warming.

"If we want to know how much a country's total emission would influence the climate, we have to take all known climate forces into account, which include well-mixed greenhouse gases, short-lived atmospheric climate forces and land-use change," said Li Bengang , a professor at the College of Urban and Environmental Sciences of Peking University.

Li's research team surveyed all known climate forces and established complex mathematical models to calculate the country's global radiative force between 1750 and 2010. They found that despite the abrupt increase in China's contribution to world CO2 emissions, the country's relative contribution remained surprisingly stable (between 8 and 12 percent) over the past 150 years.

Global radiative forcing is defined by the Intergovernmental Panel on Climate Change to refer to the extent that a factor alters energy balance of the Earth-atmosphere system in troposphere for the present day relative to 1750. Positive radiative forcing leads to surface warming, negative radiative forcing leads to surface cooling.

In the case of China, the contribution is the sum of two terms with opposite signs. For example, positive radiative forcing from well-mixed greenhouse gases, tropospheric ozone and black carbon aerosols, and negative radiative forcing from land-use change induced surface albedo changes, stratospheric ozone, the effect of ozone precursors on CH4 lifetime, and sulfate, nitrate and particulate organic matter aerosols.