Climate Justice Economy Policy

Can the World Reduce CO2 Emissions Fairly? Contraction and Convergence

Our personal CO2 emissions might be produced anywhere in the world, with the modern world’s globalised supply chains. Contraction and Convergence (of CO2 emissions) was until 2010 the basis of climate negotiations to make a fair deal between all nations for CO2 emissions reduction. It may well be again soon while the “best effort” approach of the Paris Accord’s Nationally Determined Contributions system fails to show significant progress.

If a supply chain includes both the consumer countries like the UK or the USA and the countries with cheap labour like China or India, the global carbon ration budget pie can be divided up fairly and equitably by nations to reflect this. This graph shows how – from a year 2000 perspective when it was considered the necessary basis of any future UNFCCC agreement.

Contraction and convergence: gigatonnes of historical carbon emissions and future carbon rationing, allocated on an internationally negotiated basis, as of the year 2000 - carbon rationing explained, via Carbon Watchdog
Graphic © Global Commons Institute

Contraction and Convergence (of CO2 Emissions)

The Global Commons Institute Contraction and Convergence framework is the essence of years of international climate diplomacy, as used by UNFCCC, UK Government, the Brazilian, Russian, Indian, and Chinese delegations and as a basis for proposals by various organisations and political parties ever since.

In essence, climate negotiating teams agree on a total global annual CO2 emissions figure. This is amount is then decreased year on year. This is the “Contraction” part of the framework.

Obviously the OECD countries which account for the greatest emissions start reduction immediately (the green and white swathes in the chart above, and illustrated in tonnes per capita in the upper graph).

Other countries however are allowed to carry on expanding their CO2 emissions (e.g. the blue swathe) until an agreed cut-off date. This allows for technology transfer, infrastructure build, and generally a slower, less expensive energy transition for those countries with less resources.

After the agreed cut-off date (the pale blue column) all countries are then bound to reduce their CO2 emissions to zero by the agreed end date – this is the “Convergence”.

This chart was created with climate data from the year 2000 but now in 2021 the numbers on the axes look very different. The principle remains the same though.


Cutting back the supply of fossil fuels can be done in several ways. Obviously a government can simply restrict production and import. However a system of Universal Carbon Credits backed by a Carbon Currency AKA Total Carbon Rationing would be a flexible and fair policy.

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