Sunday, February 17, 2019

Australia’s Record Hot January: Mostly Weather, Not Climate Change

February 4th, 2019 by Roy W. Spencer, Ph. D.
The Australian Bureau of Meteorology (BOM) claims January, 2019 was record-hot. There is no doubt it was very hot — but just how hot… and why?
The BOM announcement mentions “record” no less than 28 times… but nowhere (that I can find) in the report does it say just how long the historical record is. My understanding is that it is since 1910. So, of course, we have no idea what previous centuries might have shown for unusually hot summers.
The assumption is, of course, that anthropogenic global warming is to blame. But there is too much blaming of humans going on out there these days, when we know that natural weather fluctuations also cause record high (and low) temperatures, rainfall, etc.
But how is one to know what records are due to the human-component of global warming versus Mother Nature? (Even the UN IPCC admits some of the warming since the 1950s could be natural. Certainly, the warming from the Little Ice Age until 1940 was mostly natural.)
One characteristic of global warming is that it is (as the name implies) global— or nearly so (maybe not over Antarctica). In contrast, natural weather variations are regional, tied to natural variations and movements in atmospheric circulation systems.
That “weather” was strongly involved in the hot Australian January can be seen by the cooler than normal temperatures in coastal areas centered near Townsville in the northeast, and Perth in the southwest:  



The extreme heat was caused by sinking air, which caused clear skies and record-low rainfall in some areas.
But why was the air sinking? It was being forced to sink by rising air in precipitation systems off-shore. All rising air must be exactly matched by an equal amount of sinking air, and places like Australia and the Sahara are naturally preferred for this — thus the arid and semi-arid environment. The heat originates from the latent heat release due to rain formation in those precipitation systems.
If we look at the area surrounding Australia in January, we can see just how localized the “record” warmth was. The snarky labels reflect my annoyance at people not thinking critically about the difference between ‘weather’ and ‘climate change’: 



January 2019 surface temperature anomalies (deg. C, relative to the 1981-2010 average) from NOAA’s Global Forecast System (GFS) analysis fields. Unlabeled graphic courtesy of WeatherBell.com.

So, the claims of the usual suspects such as “Australia’s Extreme Heat is a Sign of Things to Come” is just one more example of the blind leading the blind.

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