The Queensland floods are not related to anthropogenic global warming

The Queensland floods are a disaster that demands our sympathy and earnest attempts to prevent similar damage in future.  But to do this properly we need to see the floods in the perspective of time, and see the history of flooding.  This is best done by concentrating on the Brisbane region simply because it has the longest historical record.

This record has been admirably collated by the Bureau of Meteorology, and the details can be seen at this site, which gives a blow-by-blow summary of the floods.

http://www.bom.gov.au/hydro/flood/qld/fld_history/brisbane_history.shtml

Below are shown the records for Brisbane and the Bremer River at Ipswich.  The variation between the two is itself of interest, showing how different records can be at relatively close locations.

This history is a necessary background to the following discussion.

One of the sidelines of disasters like the Queensland floods is that the leaders of the Anthropogenic Global Warming Campaign will try to relate the disaster to Global Warming, caused by increasing man-made carbon dioxide. This has been done for the Queensland floods by, for example,  David Karoly  who for some reason gets a lot of coverage in the press and Television in Australia (though he has no expertise in this area), and Michael Steketee, the resident AGW specialist in The Australian.

There are at least three arguments against relating the Queensland floods to Anthropogenic Global Warming.

1.Even other people in the Global Warming game realize there is no relationship between broad disasters and carbon dioxide. The leading AGW institution is the IPCC (Intergovernmental Panel on Climate Change).

Christopher Monckton wrote of an article in The Australian in January 2011:

“Mr. Steketee’s short article makes two dozen questionable assertions, [I refer only to point 18] which either require heavy qualification or are downright false. His assertions will be printed in bold face: the truth will appear in Roman face.

18. EVEN CAUTIOUS SCIENTISTS TEND TO SAY WE CAN BLAME MANMADE CLIMATE CHANGE.
Cautious scientists say no such thing. Even the excitable and exaggeration-prone IPCC has repeatedly stated that individual extreme-weather events cannot be attributed to manmade “global warming; it would be particularly incautious of any scientist to blame the blocking highs that caused nearly all of the weather-related damage in 2010 on us when these are long-established, naturally-occurring phenomena.”

2. The second problem is that this is not an isolated event.  There was another flood of about the same dimensions in 1974.  There was no peak of CO2 at that time.  It was not an especially warm year, so Global Warming cannot be invoked (1998 was a hotter year, but no flood). 

But there were even greater floods in 1841 and 1893. This is well before any possible Anthropogenic Global Warming, which began, according to its adherents, in 1945.

And there were many other floods of lower magnitude, long before the supposed advent of Anthropogenic Global Warming as shown in the BoM graphs.

3. A third problem is that just a few years ago, global warming was blamed for causing droughts. This opinion was extolled during the last drought especially by Tim Flannery, another non-expert. 

In 2003 Professor Karoly  published, under the auspices of the World Wildlife Fund, a report that claimed that elevated air temperatures, due to CO2, exacerbated the drought.

 “...the higher temperatures caused a marked increase in evaporation rates, which sped up the loss of soil moisture and the drying of vegetation and watercourses. This is the first drought in Australia where the impact of human-induced global warming can be clearly observed...”

and

“This drought has had a more severe impact than any other drought since at least 1950.... This is the first drought in Australia where the impact of human-induced global warming can be clearly observed.”

So Anthropogenic Global Warming can apparently be used to explain any current disaster.  Any hypothesis (like AGW) that uses the same mechanism to explain opposite effects is untestable, and therefore not science.  Its models are totally useless for prediction.

In brief, there is no reason whatever to associate the Queensland floods with global warming (if it is occurring at all).  It is even more ridiculous to blame it on a trivial increase in atmospheric carbon dioxide.

Unfortunately the floods will come again.  You might like to look at the data on the BoM website and try to determine the return interval for yourself.  It is really a bit of a guess. 

But the citizens of Queensland would be well advised to implement adaptation policies that have a more realistic impact than trying to reduce CO2 production in the vain hope that it will, like repeating some magic spell, make the nasty problem go away.