Archives For twisting the dragon’s tail

With the NSW Rural Fire Service fighting more than 50 fires across the state and the unprecedented hellish conditions set to deteriorate even further with the arrival of strong winds the question of the day is, exactly how bad could this get? The answer is unfortunately, a whole lot worse. That’s because we have difficulty as human beings in thinking about and dealing with extreme events… To quote from this post written in the aftermath of the 2009 Victorian Black Saturday fires.

So how unthinkable could it get? The likelihood of a fire versus it’s severity can be credibly modelled as a power law a particular type of heavy tailed distribution (Clauset et al. 2007). This means that extreme events in the tail of the distribution are far more likely than predicted by a gaussian (the classic bell curve) distribution. So while a mega fire ten times the size of the Black Saturday fires is far less likely it is not completely improbable as our intuitive availability heuristic would indicate. In fact it’s much worse than we might think, in heavy tail distributions you need to apply what’s called the mean excess heuristic which really translates to the next worst event is almost always going to be much worse…

So how did we get to this?  Simply put the extreme weather we’ve been experiencing is a tangible, current day effect of climate change. Climate change is not something we can leave to our children to really worry about, it’s happening now. That half a degree rise in global temperature? Well it turns out it supercharges the occurrence rate of extremely dry conditions and the heavy tail of bushfire severity. Yes we’ve been twisting the dragon’s tail and now it’s woken up…

2019 Postscript: Monday 11 November 2019 – NSW

And here we are in 2019 two years down the track from the fires of 2017 and tomorrow looks like being a beyond catastrophic fire day. Firestorms are predicted.