In an important new report, Sharing the effort under a global carbon budget (WWF’s announcement is here) Wildlife Fund International takes two important steps. First, it explicitly endorses the carbon budget approach as the best and most appropriate basis for setting a global emissions cap, and in so doing takes a clear step towards a scientifically defensible global climate accord. Second, it leverages this approach to do a rigorous comparison between the Greenhouse Development Right framework and two important per-capita approaches to effort sharing — Contraction and Convergence (C&C) and Common but Differentiated Convergence (CDC).
In the report, EcoFys, a widely-respected European energy research consultancy that authored it for WWF, shows exactly why GDRs more effectively protects the right to development than either of the per-capita approaches, and on this basis, WWF almost endorses GDR (which, strangely, it seems unable, even after years of debate, to remember the proper name of):
Although WWF has strong sympathy with the Greenhouse Gas Development Right Framework to distribute the allowable emissions in a social and equitable way in the next decades, at this point in time WWF is not promoting any particular approach to distribute the finite global greenhouse gas budget between 1990 and 2100. But whichever approach the world chooses in order to stay below 2°C, the cumulative greenhouse gas budget cannot change substantially. If we relax on the trajectory of one country, another country needs to pick up the bill. There is no carbon offset for Planet Earth as such.
It is important, here, to understand the difference between classical C&C and CDC. The first is a system in which ” The targets for individual countries are set in such a way that per capita emission allowances converge from the countries’ current levels to a level equal for all countries within a given period, here until 2050.” The second is a refinement of C&C in which, and in C&C, ” As above, targets are set so per capita emissions for all countries converge to an equal level over the period 2010 to 2050. For developed (Kyoto Protocol Annex I) countries’ per capita emission allowances convergence starts immediately. For individual non-Annex I countries’ per capita emissions convergence starts from the date when their per capita emissions reach a certain percentage threshold of the (gradually declining) global average.”
This is an important difference, at least in principle. In practice, however, the global emissions budget is so small that it makes little difference. So, that, in the context of an global carbon budget that is reasonably compatible with a 2C temperature cap, the two per-capita system define more or less identical emissions trajectories:
The difference makes a difference:
Developing countries in general and economies in transition (EITs) have more room to grow under GDRs than under the other approaches. The main reasons for this are the relatively low per capita emissions combined with limited financial capacity.
Least Developed Countries (LDCs) are almost all exempt from emission reduction requirements under GDRs, while under C&C they are granted little more allowances than their reference emissions until 2020 and face reduction obligations after 2025. Under CDC they face reductions after 2030.
Cumulative emissions per capita vary considerably under C&C and CDC for Annex I and non-Annex I. For GDRs some non-Annex I countries are even granted higher per capita cumulative emissions than some countries of Annex I.
Under GDRs, non-Annex I countries are allowed to increase their total emissions and peak until 2025 and then need to reduce them to roughly today’s level in 2050 (about 50% above 1990). Under C&C and CDC there is less room for growth and their emissions need to be at a third of today’s emissions (half of 1990’s emissions). This is particularly reflected in the case of China and India. Both countries would be entitled under GDR to grow their emissions by 10% and even 240%, respectively, by 2050 compared to 1990, while being required to reduce by more than 70% and about 2-7% in the same period under the other two models.
Finally, note that at the pre-Copenhagen seminar in which the report was released, WWF’s Richard Worthington, after noting that “A good outcome at the international climate change negotiations scheduled for December in Copenhagen, would be an agreement among parties that there is a need for a common carbon budget,” added that a responsibility and capability index of that shared budget would need to follow. In so doing, he made WWF’s near endorsement clear.
