23 April 2005

Emissions are not climate change

From the Economist:

Emissions trading is also taking off. America led the way with its sulphur-dioxide trading scheme, and today the EU is pioneering carbon-dioxide trading with the (albeit still controversial) goal of slowing down climate change. ... Here, politics merely sets the goal. How that goal is achieved is up to the traders.

Not quite. The goal is to mitigate climate change, not cut back on anthropogenic carbon dioxide emissions.

For sulphur dioxide, there is probably a strong correlation between amounts emitted by those (relatively few) polluters whose emissions can be accurately monitored and its adverse effects on social welfare. But this is not the case with carbon dioxide. What will emissions trading in CO2 achieve? It might put a cap on anthropogenic emissions of carbon dioxide - those at least that can be reliably monitored. It may or may not bring about a significant reduction in total anthropogenic greenhouse gas emissions. It might even limit total greenhouse gas emissions. But it does not target beneficial changes in the composition of the atmosphere. And it does nothing to encouarge those who find ways of mitigating climate change other than reduce CO2 emissions.

It is in short an indirect and tenuous way of cutting back one possible driver of climate change. If imposed in a way that will have any effect on emissions at all, it will be expensive, divisive and almost certainly ineffectual if its real goal is actually to mitigate climate change.

Here's another idea: instead of targeting anthropogenic CO2 emissions, reward people who mitigate climate change however they do so. Better still, offer market incentives, so that people not only to do the right thing, but do it efficiently. In other words: issue Climate Stability Bonds.

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