11 March 2008

Carbon targets to manage climate change

This is a follow-up to an earlier posting (see "Prevention of climate change without binding targets?" posted on 12 December 2007) where I said that the only way forward is a strategy based on uniform carbon emission allowances per person. In some countries the principle is making its way into government policy. Here are two figures from the Interim Report to the Commonwealth, State and Territory Governments of Australia (the first draft of the so-called Garnaut Climate Change Review).

The first figure shows the total CO2 emissions, including those from land-use, for 2004; units are gigatons, the scale is on the left. Squares show per capita emissions, in tons on the right-hand scale. I added the yellow line to the figure; it shows the acceptable per capita emission if we assume that the world has to return to the total emissions it produced in 1990.

The second figure is a sketch (the Garnaut report calls it "a stylised, illustrative scenario") of what has to happen if we want to stabilize the climate. The y-axis gives per capita emissions, the x-axis time, both without units. The figure demonstrates the huge change in lifestyle the USA and Australia have to undergo if they are to reach their per capita targets. The European Union and Japan are under far less pressure but have to reduce their per capital consumption, too. With the numbers adopted by the Garnaut report China has not quite reached the maximum acceptable per capita consumption (which means that my yellow line in the first figure was drawn somewhat too far down on the scale) but will reach it soon, while India is not in such a tight situation.

The Garnaut report was commissioned to form the basis for Australia's climate change policy. Hopefully the Australian government will adopt it in full. Any delay in adoption of the percapita emission principle will cause more damage to the environment.