A fourth edition on climate change

The Economist reports on the release of the 12 page summary of the fourth assessment report of the Intergovernmental Panel on Climate Change (IPCC). This release has been material for widespread headlines in the MSM to the effect of long term, unstoppable, human caused global warming. The full report may not come out for a few months as it is being ‘adjusted’ to make sure it is at least politically or ideologically correct or doesn’t offend too many of the hard core activist types.

One part of the report’s job is to consider studies of the speed of change so far. This looks omnious until you look at how small the changes really are over how short a time span.

The other part of the report’s job is to make predictions about what will happen to the climate. In this, it illustrates a curious aspect of the science of climate change. Studying the climate reveals new, little-understood, mechanisms: as temperatures warm, they set off feedback effects that may increase, or decrease, warming. So predictions may become less, rather than more, certain. Thus the IPCC’s range of predictions of the rise in the temperature by 2100 has increased from 1.4-5.8C in the 2001 report to 1.1-6.4C in this report.

That the IPCC should end up with a range that vast is not surprising given the climate’s complexity. But it leaves plenty of scope for argument about whether it’s worth trying to do anything about climate change.

This points out some improvements being made supporting a more honest discussion. There is the fact that what we know is rather incomplete and the uncertainty in prediction is quite large. Good science deals with levels of confidence in matters of precision and accuracy and much of the ‘debate’ on climate in recent years has tended to ignore them.

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