sitive, the fundamental problem of how to divide up necessary greenhouse gas reductions between developed and developing countries remains. And with the Copenhagen UN climate summit less than two months away, breaking this deadlock between the major developed and developing economic powers will be essential for progress towards the goal of forging a comprehensive global climate treaty.
The 2C target requires that cumulative greenhouse gas emissions, expressed as carbon dioxide equivalents, do not exceed about 1,600bn tons over the next four decades. Developing countries want national emissions allowances to be allocated on the basis of equity of per capita emissions. Developed countries argue that this approach would subject them to politically and economically unacceptable emissions restrictions, and that the lack of binding emissions targets for developing countries would frustrate efforts to meet the 2C climate goal.
A realistic compromise that can break the deadlock is possible, based on a less strict version of the per capita emissions equity principle. The compromise, which we term “progressive convergence”, would involve developed countries agreeing to make an early start on emissions reductions and developing countries committing never to exceed the average per capita emissions of developed countries – a commitment that India in fact has indicated that it would be willing to make.
The net result will be a progressive convergence of nations to a declining per capita emission rate. To meet the 2C goal, the developed countries’ reduction targets must be sufficiently stringent, but not so stringent as to be politically or economically unacceptable.
Consider, for example, carbon dioxide emissions from the consumption of fossil fuels. If the G8 countries as a bloc were to adopt the emissions targets similar to those in the Waxman-Markey bill that was passed by the US House of Representatives in June, their average annual per capita energy-related carbon dioxide emissions would decline from about 13 tons currently to less than two tons by 2050.
Under the progressive convergence principle, other countries would be allowed to increase their emissions until their per capita emissions equalled that of the G8 bloc, and thereafter be required to mirror the declining per capita emissions of the G8 bloc.
Our calculations, using emission projections by the US Energy Information Agency, indicate that the non-G8 European OECD bloc would hit the per capita emissions of the G8 bloc and have to commence emissions reductions around 2025. Developing economies such as Mexico and Brazil would commence reductions around 2040-2045. Per capita emissions in China would converge with the G8 around 2030, while India’s per capita emissions would not converge until around 2050, owing to its much lower per capita emissions today and projections of smaller emission growth rate and continued increase in population through 2050.
In this scenario, cumulative energy-related carbon dioxide emissions between 2010 and 2050 would total about 1,200bn tons, leaving about 400bn tons for non-energy-related greenhouse gas emissions. To keep these emissions below 400bn tons, complementary reductions in emissions from deforestation and land use change, as well as other greenhouse gases, will also be necessary. After 2050, emissions reductions will still be needed, but with all the major nations now on an equal per capita carbon footing.
The common perception that climate goals can be met only if large developing economies such as China and India commit to immediate emissions reductions, or if developed countries adopt draconian measures, is incorrect. Early action by developed countries to reduce greenhouse gas emissions, coupled with a commitment by developing countries to adhere to the progressive convergence framework, can be the basis of an agreement that is consistent with both the “common but differentiated responsibility” principle of the UN Framework Convention on Climate Change and the goal of not exceeding a 2C increase in global temperatures above pre-industrial levels.