Researchers: history of anthropogenic climate change has consequences for global equity

Two months ago, nations were negotiating in Bangkok over the wordings of the IPCC's report on how to mitigate climate change. Discussions did not go smoothly as rapidly developing nations, in particular China, India and Brazil, brought up the topic of global equity and the historic responsibilities of the highly industrialised countries. The developing nations, who used to be outside of the Kyoto Protocol's obligations, did so because they feared that a post-Kyoto agreement that is currently in the making might eventually threaten their economies, which are very energy intensive and largely rely on fossil fuels.

China just recently unveiled its own take on climate change mitigation, squarely putting economic growth first, and once again stressing that the highly developed economies - the EU, the US and to a lesser extent Japan and Russia - carry so large a burden of past greenhouse gas emissions, that they must be held responsible for the future effects of this past pollution. They have the obligation to reduce greenhouse gas emissions first.

To put the argument in other words: the Americans and the Europeans have had the privilege of being allowed to use massive amounts of climate destructive fossil fuels for more than 200 years, have deforested all their lands and gained so much prosperity in the process, that they are now so powerful and prosperous that they can 'green' their own economies with relative ease, while lecturing developing countries on which kind of industrialisation path (not) to follow. The developing countries ask for a more equitable approach.

This topic of historic responsibilities has always haunted negotiations on ways to mitigate climate change. A group of researchers from CSIRO's Global Carbon Project, the Carbon Dioxide Information Analysis Center of the Oak Ridge National Laboratory, the Commissariat à l’Energie Atomique of France's Laboratoire des Sciences du Climat et de l’Environnement, Germany's Kiel Institute for the World Economy and the Carnegie Institution's Department of Global Ecology now offer an interesting overview of the facts behind this debate. Their discussion is published as an open access article in the May 22 early edition of the Proceedings of the National Academy of Sciences.

Cumulative emissions
The researchers look at the global and regional drivers of accelerating CO2 emissions, with an eye on the past. To do so, they analyse trends of the carbon intensity of the economies of a series of regions and countries. What immediately strikes is the fact that (click graph 1 to enlarge):

the developing and least developed economies (China, India, D2, and D3), representing 80% of the world’s population, accounted for 73% of global emissions growth in 2004. However, they accounted for only 41% of global emissions in that year, and only 23% of global cumulative emissions since the start of the industrial revolution.

The researchers note that such "a long-term (multidecadal) perspective on emissions is essential because of the long atmospheric residence time of CO2". It is precisely this argument that countries like China, India and Brazil are increasingly using as the basis of their vision on how the international community should divide responsibilities for mitigating climate change:
bioenergy :: biofuels :: energy :: sustainability :: climate change :: greenhouse gas emissions :: fossil fuels :: energy intensity :: carbon intensity :: equity :: history ::

The researchers draw on the so-called 'Kaya-identity' of economies (which consists of a set of factors such as population growth, GDP growth, the carbon intensity of energy, the carbon intensity of GDP) to find a grim picture on global and regional emissions growth trends. Emissions from fossil-fuel burning and industrial processes have been accelerating at a global scale, with their growth rate increasing from 1.1% per year for 1990–1999 to 3% per year for 2000–2004. They find that the emissions growth rate since 2000 was greater than for the most fossil-fuel intensive of the Intergovernmental Panel on Climate Change (IPCC) emissions scenarios developed in the late 1990s.

To understand what this means, a quick overview of these IPCC emissions scenarios.

The Emission Scenarios of the IPCC Special Report on Emission Scenarios (SRES)

A1. The A1 storyline and scenario family describes a future world of very rapid economic growth, global population that peaks in mid-century and declines thereafter, and the rapid introduction of new and more efficient technologies. Major underlying themes are convergence among regions, capacity building and increased cultural and social interactions, with a substantial reduction in regional differences in per capita income. The A1 scenario family develops into three groups that describe alternative directions of technological change in the energy system. The three A1 groups are distinguished by their technological emphasis: fossil intensive (A1FI), non-fossil energy sources (A1T), or a balance across all sources (A1B) (where balanced is defined as not relying too heavily on one particular energy source, on the assumption that similar improvement rates apply to all energy supply and end use technologies).

A2. The A2 storyline and scenario family describes a very heterogeneous world. The underlying theme is self reliance and preservation of local identities. Fertility patterns across regions converge very slowly, which results in continuously increasing population. Economic development is primarily regionally oriented and per capita economic growth and technological change more fragmented and slower than other storylines.

B1. The B1 storyline and scenario family describes a convergent world with the same global population, that peaks in mid-century and declines thereafter, as in the A1 storyline, but with rapid change in economic structures toward a service and information economy, with reductions in material intensity and the introduction of clean and resource efficient technologies. The emphasis is on global solutions to economic, social and environmental sustainability, including improved equity, but without additional climate initiatives.

B2. The B2 storyline and scenario family describes a world in which the emphasis is on local solutions to economic, social and environmental sustainability. It is a world with continuously increasing global population, at a rate lower than A2, intermediate levels of economic development, and less rapid and more diverse technological change than in the B1 and A1 storylines. While the scenario is also oriented towards environmental protection and social equity, it focuses on local and regional levels.

As can be seen in graph 2 (click to enlarge), actual emissions in recent years have followed the worst-case scenario (A1FI), with rapid economic growth, an emphasis on fossil fuels and no major switch to low-carbon technologies:

Continuous decreases in both e [energy intensity of the world economy] and f [carbon-intensity of energy] are postulated in all IPCC emissions scenarios to 2100, so that the predicted rate of global emissions growth is less than the economic growth rate. Without these postulated decreases, predicted emissions over the coming century would be up to several times greater than those from current emissions scenarios. In the unfolding reality since 2000, the global average f has actually increased, and there has not been a compensating faster decrease in e. Consequently, there has been a cessation of the earlier declining trend in h [the carbon intensity of world GDP]. This has meant that even the more fossil-fuel-intensive IPCC scenarios underestimated actual emissions growth during this period.

No economy is decarbonising its energy supply
Global emissions growth since 2000 was driven by a cessation or reversal of earlier declining trends in the energy intensity of gross domestic product (GDP) (energy/GDP) and the carbon intensity of energy (emissions/energy), coupled with continuing increases in population and per-capita GDP. Nearly constant or slightly increasing trends in the carbon intensity of energy have been recently observed in both developed and developing regions. No region is really decarbonizing its energy supply.

More information:
Michael R. Raupach, Gregg Marland, Philippe Ciais, Corinne Le Quéré
, Josep G. Canadell, Gernot Klepper, and Christopher B. Field, "Global and regional drivers of accelerating CO2 emissions", Proc. Natl. Acad. Sci. USA, Published online before print May 22, 2007, DOI: 10.1073/pnas.0700609104