Developing countries’ contributions to climate change approach 50%

Discussions at the UN climate negotiations tend to focus on which countries have contributed most to climate change. In a recent article, researchers of PBL, Ecofys and JRC argue that there are several ways to calculate countries’ contributions to climate change, with widely varying outcomes.

In the article, which was published in the international journal Climatic Change and is now available in print, the authors compare several ways of calculating historical emissions and assess the effect of these different approaches on countries’ relative contributions to cumulative global emissions.

Discounting historical emissions for technological progress, for example, reduces the relative contributions of some developed countries and increases those of some developing countries, in total to 52%. This variant takes into account that emerging economies benefit from technologies that have been developed earlier elsewhere. Another variant, one that is often used by experts from developing countries, excludes recent emissions (2000-2010), non-CO₂ greenhouse gases, and land-use change and forestry CO₂. This increases the relative contribution of developed countries as a group to as high as 80%. From a scientific perspective, however, it is preferable to include all greenhouse gases, as well as the most recent emission trends, as was done in the reference calculations in this paper.

The results presented in this paper show the importance of the choices made when calculating historical contributions of countries. Such choices have to be made by the policy makers when negotiating a future international climate agreement. Providing the transparency in this paper on the implications of such choices can help governments to do so.