Australian Heat Waves: Ode to Adelaide

What with Australia’s record-breaking multiple-heat-waves January, amidst talk of frying eggs on the sidewalk and melting asphalt and bats dropping dead because their brains cooked in the afternoon heat, we’ve looked at temperatures down under. We’ve noted overall warming, and the increase in the number of hot days. But we haven’t specifically looked at heat waves, which require multiple hot days in a row — usually, 3 or more, which is what we’ll go with.

The city of Adelaide, capitol of South Australia, has been in the news for setting a new record: hottest temperature in Australia ever recorded in a major city, at 46.6°C (115.9°F). It sounds a bit iffy to say “in a major city,” but I’ll let Adelaide have its day and look at its past heat waves.

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Climate Forcing

Readers have recently discussed the correlation through time between global temperature on the one hand, and CO₂ concentration on the other. Close examination shows that the correlation is stronger during some time intervals, weaker during others, and although it’s strong overall, there seems to be a lot happening to temperature other than mimicry of the CO₂ changes.

One suggestion was to study the relationship, not with CO₂ concentration, but with its logarithm. This is because climate forcing — a measure of the ultimate climate-changing impact — is proportional to the logarithm of the CO₂ concentration, not to the concentration itself. The idea is to look for correlation between temperature and climate forcing — and it makes sense.

The fascinating thing is: there are many different climate forcings. A lot more than just CO₂.