A conversation
In the wake of our 2025 floods (Jan 28 – Feb 12), North Queensland Conservation Council posted a call to action on facebook. I agreed with it and then tried to say why the “1-in-100-year event” label has become so obviously misleading.
NQCC: Floods and heatwaves are the new normal.
North Queensland has been hit hard again, and these so-called “1-in-100-year events” are happening way too often. Climate change is making extreme weather more frequent and intense, yet our leaders still aren’t taking the urgent action we need. …Malcolm Tattersall: “1-in-100-years” is a (sort of) average and what it really means is that there is one chance in one hundred of such a flood occurring in any given year. But that measure is purely statistical and historical. As such, it relies on the future being like the past, and climate change has completely undermined its validity.
The calculation is really very simple – too simple, in fact, to include any of the changes (e.g. urbanisation, dam construction, climate change) which might make nonsense of the prediction.
That was enough for facebook but pursuing the science further seems worthwhile.
Continue reading “Too many 1-in-100-year floods”