I’m sure everyone’s seen the pictures on the news of the dramatic and distressing floods in Queensland, north-eastern Australia. As expected, global warming was blamed for the floods by some, though most news outlets have so far resisted the temptation. Heavy and sustained rainfall is not uncommon in north-eastern Australia, though the recent increase in rainfall is remarkable.
So what was the IPCC regional impact prediction for the area – more rainfall and subsequent flooding? Of course not. Remember, when the last report was compiled, there was a drought, so strangely enough, the IPCC found that droughts would become more frequent as “a change in climate toward drier conditions” took hold there:
Using a transient simulation with the NCAR CCMO GCM at coarse resolution (R15) (Meehl and Washington, 1996), Kothavala (1999) found for northeastern and southeastern Australia that the Palmer Drought Severity Index indicated longer and more severe droughts in the transient simulation at about 2xCO2 conditions than in the control simulation. This is consistent with a more El Niño-like average climate in the enhanced greenhouse simulation; it contrasts with a more ambivalent result by Whetton et al. (1993), who used results from several slab-ocean GCMs and a simple soil water balance model. Similar but less extreme results were found by Walsh et al. (2000) for estimates of meteorological drought in Queensland, based on simulations with the CSIRO RCM at 60-km resolution, nested in the CSIRO Mk2 GCM.
That’s right – the IPCC prediction for north-east Australia (Queensland) was less rainfall, more droughts, and a generally drier climate. In fact, the regional impact report speculates on the effect that “A change in climate toward drier conditions as a result of lower rainfall and higher evaporative demand” would have on Queensland.
And what about the possibility of flooding caused by increased rainfall? Nothing. Not one word.