Anthony Albanese has made a simple and common mistake in his understanding of the flood events that deluged large parts of Australia in recent months.
Mr Albanese did not blame climate change explicitly for the floods but said one-in-100-year events were happening more regularly. In reality, a one-in-100-year event does not mean it will happen once every 100 years.
Rather, it means that there is a 1 per cent chance it will happen in any given year.
Mr Albanese can be excused for getting a distorted view of what’s happening given his travel demands, having visited Tasmania, Victoria, NSW, South Australia and now Western Australia since becoming prime minister, to inspect the damage.
The meteorological processes at play are well understood. Three consecutive La Nina weather patters have left the eastern seaboard soaked and prone to flooding. Triple La Ninas have happened four times in the Bureau of Meteorology’s 120-year record.
The other weather systems at play have been a negative Indian Ocean Dipole in winter and spring, and a persistently positive phase of the Southern Annular Mode from mid-autumn.
The IOD is the difference in ocean temperatures between the west and east tropical Indian Ocean. A positive IOD in 1982 coupled with an El Nino weather system in the Pacific produced southeast Australia’s driest year on record. With a La Nina and negative IOD, we have been experiencing the opposite to that.
The Southern Annular Mode, or SAM, is a climate driver that can influence rainfall and temperature. Although wet, the latest BoM figures show that 2022 was the ninth-wettest year on record.
Wet conditions helped make 2022 the 22nd-warmest year since national temperature records began in 1910.
The scientific reality remains that no single weather event can by definitively attributed to a warming climate.
And given the high level of natural variability in Australia’s weather record, it will be some time before the evidence of this happening becomes unmistakably apparent.