Claims Of More Extreme Rain In Australia Disproved By Facts
By Paul Homewood
More rain on the horizon as climate change affects Australia, study finds
Australians will need to batten down the hatches with more intense rain storms predicted as a result of higher humidity driven by a rise in global temperatures.
New findings from the ARC Centre of Excellence for Climate System Science, published in Nature Climate Change on Tuesday, reveal that a two-degree rise in average global temperatures would lead to a 10-30 per cent increase in extreme downpours.
The study’s authors predict that while some parts of the continent will become wetter, others will experience increasing drought.
Steve Sherwood, a professor at the Climate Change Research Centre at the University of NSW who contributed to the research, said global warming would have a clear impact on rainfall.
“There is no chance that rainfall in Australia will remain the same as the climate warms,” he said.
“With two degrees of global warming, Australia is stuck with either more aridity, much heavier extreme rains, or some combination of the two.”
We had a good laugh at this latest piece of junk science earlier, but just what have been the trends in extreme precipitation in Australia?
The Australian BOM has some useful tools for analysing extreme trends (please take note, Met Office).
For instance, we can look at annual total precipitation when daily precipitation > 99th percentile:
Or the annual maximum 1-day precipitation total:
Both show a similar pattern with a peak in 1974, and no evidence at all of extreme rainfall increasing in recent years.
Of course, these only show the average for Australia as a whole, so could hide opposing trends in different parts of the country.
To get around this, the BOM also provide trend maps.
Using the same two categories, we can see that there are relatively few areas where extreme rainfall has been on the rise, and certainly none where the increase has been significant.
Moreover, there does not even seem to be any obvious regional pattern where extreme rainfall has been getting worse.
On the contrary, all of the evidence points to some places seeing less extreme rainfall.
We can also do the same with drought statistics:
Again, the evidence clearly points to drought becoming less of a problem across most of the country, something that is borne out by annual rainfall statistics:
Sherwood might have programmed his models to say that a warmer climate brings heavier rain/more drought, but history says otherwise.
Full analysis on extremes is available from BOM here;
BOM explanation on how they calculate is here: