South Pole Warming: Natural Variability Vs Computer Models

Have you noticed that in many scientific papers there is often a change of direction somewhere in the text when the obvious conclusion emerging from the data is ambushed by an idea the authors just can’t leave out?

It happens often in climate change papers when messy real world data that might not be playing out as expected is tortured to confess that it’s consistent with what could be expected from computer models.According to a recent paper in Nature Climate Change over the past three decades the air temperature at the south pole has warmed by 0.61 +/- 0.34°C per decade or about three times faster than the rest of the world. The researchers say this lies within the upper bound of natural variability for the region. That may be so but they are also determined to show a significant anthropogenic influence in the data by using computer modelling.

Natural and anthropogenic climate variability in Antarctica is complex. Although many consider that grounded ice sheets control the weather patterns of much of the southern hemisphere, little is known about the drivers of climate variability in Antarctica. According to the researchers climate models “do a poor job.”They find the south pole warmed by 1.8°C between 1989 - 2018, and that warming in western Antarctica stopped whilst warming in the Antarctica peninsula also stopped. They suggest that warm air responsible for the warming at the south pole itself has been sent up to the Antarctic plateau by stronger low-pressure systems and stormier weather east of the Antarctic Peninsula in the Weddell Sea.

This is interesting research into decadal changes at the south pole certainly and with the data being explainable by natural variability. The researchers then examine some 200 climate model simulations to see how many of them can reproduce the data. They find that the observations exceed 99.9 per cent of the computer models without human influence. Their conclusion is that the warming seen at the south pole is anthropogenic. An alternative viewpoint and one that would be consistent with the researcher’s comments about models doing a poor job would be to discard the models as wrong. But no, this time they are correct!To summarise. The observations of south pole warming suggest they are at the high end of natural variability. Antarctic climate models are poor. However, in this instance they are good enough to verify that the data has an overwhelming anthropogenic influence. There is a certain self-serving use of logic here.

To put this research into context it should be noted that of the ten coastal weather stations in Antarctica none have warmed in the past decade. Satellite data shows that as a whole the Antarctic hasn’t warmed since 1979 even though some researchers suggest that over the past 60 years East Antarctica has cooled whilst the much smaller West Antarctic has warmed. I said it was complicated.

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