Contraction and convergence

The interim version of the Garnaut Review (mentioned earlier) includes a numberless graph illustrating what the principle of contraction and convergence in per capita greenhouse gas emissions would resemble:

Contraction and convergence graph from the Garnaut Review

A few features are especially notable. The first is the relative trajectories in the opening years. States with very high per capita emissions, like Australia and Canada, would have to reduce emissions sharply right from the outset. Rapidly growing poor states like China would be allowed to grow until per capita emissions are comparable to those in relatively low emission developed states, such as the EU. Gradually, everybody’s per capita emissions become lower and more similar.

This approach becomes a lot more politically feasible when you take these lines to represent emission allocations rather than actual emissions. Developing states would have a choice about how to use the extra space allocated for their development. They could opt to use the allocation for their own emissions, allowing the growth of GHG emitting industry; alternatively, they could sell the allocations to more developed states at a globally established market price. That way, poverty reduction and development goals could be served at the same time as total GHG emissions trend towards a sustainable level. The big advantage of allowing global trading is that it should equalize the international marginal cost of abatement. In simple terms, that means that it will ensure that the emissions that can be avoided at the lowest cost will be addressed first, minimizing the overall cost of mitigation.

The Garnaut Review rightly highlights that it would be incredibly politically difficult to establish such an international regime. At the same time, it is probably also right to say that a general approach that embraces contraction and convergence has the best chance of stabilizing global greenhouse gas emissions at a level that avoids dangerous anthropogenic interference in the climate system, and does so in a way that minimizes total costs and manages the distribution of costs and benefits in an acceptably fair manner.

Author: Milan

In the spring of 2005, I graduated from the University of British Columbia with a degree in International Relations and a general focus in the area of environmental politics. In the fall of 2005, I began reading for an M.Phil in IR at Wadham College, Oxford. Outside school, I am very interested in photography, writing, and the outdoors. I am writing this blog to keep in touch with friends and family around the world, provide a more personal view of graduate student life in Oxford, and pass on some lessons I've learned here.

23 thoughts on “Contraction and convergence”

  1. That does look like a fair sort of progression. The biggest question that jumps out of that graph is “will it be politically acceptable to force Americans to follow their downward-sloping line during the period when people in China are still trending upward?”

  2. R.K.

    Political acceptability is certainly a big problem. That said, contraction and convergence has some hope of (a) solving the problem (b) being feasible and (c) seeming fair.

  3. ‘Stabilizing climate requires near-zero emissions’
    A new climate science paper calls for dramatic action

    Avoiding climate catastrophe will probably require going to near-zero net emissions of greenhouse gases this century. That is the conclusion of a new paper in Geophysical Research Letters (subs. req’d) co-authored by one of my favorite climate scientists, Ken Caldeira, whose papers always merit attention. Here is the abstract:

    Current international climate mitigation efforts aim to stabilize levels of greenhouse gases in the atmosphere. However, human-induced climate warming will continue for many centuries, even after atmospheric CO2 levels are stabilized. In this paper, we assess the CO2 emissions requirements for global temperature stabilization within the next several centuries, using an Earth system model of intermediate complexity. We show first that a single pulse of carbon released into the atmosphere increases globally averaged surface temperature by an amount that remains approximately constant for several centuries, even in the absence of additional emissions. We then show that to hold climate constant at a given global temperature requires near-zero future carbon emissions. Our results suggest that future anthropogenic emissions would need to be eliminated in order to stabilize global-mean temperatures. As a consequence, any future anthropogenic emissions will commit the climate system to warming that is essentially irreversible on centennial timescales.

  4. Pingback: The Age of Stupid
  5. China’s greenhouse gas emissions will peak between 2030 and 2040, the country’s science and technology minister said Monday, as crunch talks on climate change were getting under way in Copenhagen.

    Wan Gang said the precise timing of the level would depend on China’s economic growth, rate of urbanization, and level of scientific development.

    “There are some uncertainties here, so it is difficult to say whether it will be in the beginning, the end, or the middle, but I can say for sure it will be within that range (of 2030-2040),” he told the Guardian.

    China, the world’s largest carbon gas polluter, has promised to make gains in energy efficiency, but has yet to announce a peak date for emissions.”

  6. Hans Rosling and the magic washing machine

    What was the greatest invention of the industrial revolution? Hans Rosling makes the case for the washing machine. With newly designed graphics from Gapminder, Rosling shows us the magic that pops up when economic growth and electricity turn a boring wash day into an intellectual day of reading.

  7. The LMDC argued that its member countries should not be forced onto the same timeline to cut emissions as the industrialized world when they have done little to contribute to historic emissions and may want to use fossil fuels in their own economic development, as wealthier nations have.

    This argument is not new. The recognition that different countries have different responsibilities for and capabilities to address climate change is at the heart of the U.N. negotiation process. It was also embedded in the 2015 Paris Agreement, which says that emissions should peak sooner in developed countries than elsewhere. And yet rich countries have delayed taking action to cut their own emissions for more than a decade, and now are demanding that the whole world commit to net-zero. In September, U.S. climate envoy John Kerry went to India to urge Prime Minister Narendra Modi to set a net-zero target. A few weeks ago, U.K. politician and COP26 president Alok Sharma called on G20 countries, some of which are members of the LMDC, like China, Indonesia, and Saudi Arabia, to step up now and set a net-zero target.

    The LMDC put forward a different framework. The bloc proposed that rich countries get on the fast track, fully decarbonize by the end of this decade, and “leave the remaining atmospheric space” for carbon emissions to the developing world.

  8. One way to look at the problem, which has long been popular with Indian climate negotiators, is through carbon budgets. To a close approximation the level at which carbon dioxide will peak, and thus the amount of anthropogenic warming the world will undergo, depends on the total amount dumped in the atmosphere. According to the latest ipcc report, a 50% chance of keeping temperatures below 2°C requires keeping total emissions below 3.7trn tonnes. The report also reckons that, all told, 2.4trn of those tonnes have already been emitted through industrialisation and deforestation, mostly to the benefit of the 1bn or so people who live in the rich world. This means that only 1.3trn tonnes of emissions are left in the 2°C budget for more than 6bn other people, 4bn or so of them Asian, who might reasonably aspire to reach similar standards of living, or to want them for their children.

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