The NSW coast is burning in winter. Is the end nigh? No. It’s happened before. Australia has about 50,000 bushfires a year. Very few are killers. The best predictor of a bad bushfire year is drought. One wet winter won’t end this severe drought, but it will help. It’s been very wet in WA, good in SA and western Victoria, but not so wet around Melbourne. All eyes are on the spring rains, which have failed abysmally in recent years. Runoff is still pathetic in many regions. Queensland is laughing, but southern dams are years away from filling.
But maybe the southern drought is permanent.
Reading the Sunday Age in a Sunday daze, my gob was smacked by the following revelation: “Scientists studying Victoria’s crippling drought have, for the first time, proved the link between rising levels of greenhouse gases and the state’s dramatic decline in rainfall.” So said Melissa Fyffe in The Sunday Age on August 30. The “proof” is that climate modelling shows that the continental high-pressure systems that have blocked the wet westerly fronts for the past 13 years are intensifying. Rain fronts are thus forced south, missing the Australian coast. This happens in every drought, of course, but models suggest that anthropogenic greenhouse gases are the cause, therefore the change is permanent.
Fyffe’s adamantine conclusion is not supported by the very Bureau of Meteorology source she quotes. He says “it’s reasonable” to believe that anthropogenic global warming is causing most of the problem. Hardly proof. Fyffe then retreats to “not all experts agree”, quoting one who rejects the argument.
Scientists cringe at the epidemic of tabloid climatic hyperbole. The Queensland and NSW north coasts were deluged several times earlier this year. One priceless report told us it was “the third time in six months the region had experienced once-in-a-hundred-year floods”. With a welcome touch of satire, a smirking ABC Landline reporter said another district had its “second once-in-a-century flood in a few weeks”.
The great drama of our time is climate change. It is bedevilled by three confusions: weather versus climate, local versus region versus global, and short memories.
Climate change deniers in WA, SA and Victoria are chortling. It’s been a wet winter. In Tasmania, they’re manic. The state’s been swamped. Record rainfall in some places. Those puny westerly fronts have smashed the “AGW intensified continental high-pressure thugs.
Alas, one swallow doesn’t make a pub crawl.
Cherry-picking extreme weather events weakens your case. Both sides do it shamelessly.
Australia is a continent. Recorded history is very short in climatic terms. Long droughts are normal. We just don’t know the deeper rhythms of the country, if there are any. Local records are broken all the time, somewhere. Different regions suffer drought or flood or fire simultaneously. The Dorothea Mackellar syndrome. Just like now. Tasmania floods while NSW burns. Unprecedented? No. Neither was Black Saturday. People forget. Officials feign amnesia. Why are there no fire historians and journalists? Don’t answer that. Just listen to the trams.
Climate science is in its infancy and may never grow up. We have little idea what drives climate variability, apart from vague awareness of oceanic temperatures. Regional variations are huge and opaque. We don’t know how the 0.4 degrees of global warming since 1970 is affecting continental, let alone regional climate. Global warming has levelled off in the past decade, fuelling increasingly shrill polemic from AGW deniers and believers. But whether the global temperature rises or falls in future tells us little about regional Australian climates in the medium term. Therefore long-term bushfire prediction remains guesswork.
Just look at official long-term weather predictions. The current spring forecast for most of the country is numbing: “the chance of a wetter-than-average season is between 40% and 50%. In other words the chances of above-normal falls are about the same as the chances of below normal.” For most of the SW the odds are a bit higher and for the SE a tad lower. But last April and June the bureau was predicting lower rainfall in Tasmania, SA and Western Victoria. They were wrong.
Well, are we going to burn again this summer? The drought continues. A dry spring and hot summer will produce severe bushfire risk. Last summer’s rainfall map is salutary. Great rain in the north, mostly average elsewhere. But look at the hills north and east of Melbourne…