Contraction and convergence

February 27, 2008

in Economics, Politics, Science, The environment

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.

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{ 9 comments… read them below or add one }

R.K. February 28, 2008 at 9:54 am

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?”

R.K. February 28, 2008 at 9:57 am

This comic will probably serve as a funny reminder of your student days

Milan February 28, 2008 at 11:08 am

The comic is accurate and amusing. Anything about the biochemistry of caffeine has appeal to me.

Milan February 28, 2008 at 11:09 am

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.

. February 29, 2008 at 11:34 am

‘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.

. October 29, 2009 at 12:05 pm

World carbon emissions, by country: new data released

The US is no longer number one emitter of carbon dioxide, having been overtaken by China in these latest figures. But when did it happen?

. December 9, 2009 at 3:21 pm

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.”

Aubrey Meyer May 17, 2010 at 11:55 am

Here is a presentation/animation that relates to the [mis]handling of C&C at COP-15 last December: –
http://www.tangentfilms.com/AF.swf

As Ross Garnaut correctly said, “the rate of convergence is the main equity-lever [in C&C].”

. April 19, 2011 at 8:35 pm

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.

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