Princeton: new method allocates nations’ carbon emissions

A research team has developed a new way to allocate carbon emissions responsibility among nations. The method uses a new fairness principle based on the “common but differentiated responsibilities” of individuals rather than nations.

The team, led by Princeton University scientists, has outlined their new method in a paper titled “Sharing Global CO2 Emissions among 1 Billion High Emitter” published online in the Proceedings of the National Academy of Sciences.

"Our proposal moves beyond per capita considerations to identify the world's high-emitting individuals, who are present in all countries," the team says in the introduction.

The authors hope that it will win support from both developed and developing nations which are often at odds over perceived inequalities in previous proposals of allocating carbon emissions responsibility.

Some present strategies that employ averages of energy use in a country are widely regarded as unfair, the authors say, because such efforts mask the emissions of wealthy, high polluters. The authors noted that in 2008, half of the world’s emissions came from 700 million people whose lifestyles involved high emitting behaviors such as frequent airplane flights, car use, and the heating and cooling of large homes.

The proposal would use individual emissions as the best, fairest way of calculating a nation’s responsibility to curb its output of carbon dioxide. The method does not mean that individuals would be singled out, only that these calculations would form the basis of a more equitable formula.

The researchers calculated the emission reduction targets for a country using a multi-step method. First, they used a strong correlation between income and emissions to estimate the emissions of individuals in every country. Next, they combined these factors to see how individual emissions are distributed globally.

The researchers believe their new framework is useful in that it establishes a uniform “cap” on emissions that individuals should not exceed. By counting the emissions of all the individuals who are projected to exceed that level, the world leaders could provide emissions reductions for every country.

At present, the world average for tons of carbon dioxide emitted a year per individual is about five. Each European produces about 10 tons a year, with each American producing twice that amount.
The new research paper also shows that it is possible to reduce poverty while cutting carbon emissions. The authors calculate that addressing extreme poverty by allowing almost three billion people to satisfy their basic energy needs with fossil fuels does not interfere with the goal of fossil fuel emissions reduction. The cap would need to be somewhat lower, and high emitters would need to reduce their energy consumption by a slightly larger percentage to make up the difference.

The work is part of the Carbon Mitigation Initiative, which is based at Princeton. Launched in 2000, the project has produced new practical approaches to managing the carbon dioxide emissions that contribute to global warming. The initiative is aimed at supporting fundamental scientific, technological, and environmental research that would lead to safe, effective, and affordable solutions to climate change.

World leaders are expected to meet in Copenhagen in December 2009 for a conference to negotiate a treaty on global emissions reductions to address climate change. The 1992 United Nations Framework Convention on Climate Change called upon the developed nations to reduce carbon emissions and provided the impetus for the binding 1997 Kyoto Protocol, but established no time frame for developing countries to follow.

- Katrice R. Jalbuena