While this is a bit dated, from late last year, given all the attention given to the floods in Queensland supposedly being caused by global warming aka climate change, this seemed relevant to review. h/t to reader Baa Humbug and Andrew Bolt
“Ongoing research is examining whether increased temperatures linked to climate change in the future will alter the frequency, intensity, and duration of drought. We are also investigating if the rising temperature due to climate change has played a part in the unprecedented low water storage level of the recent drought and how climate change will impact on climate variability.”
The study centred on the contribution to rainfall by naturally occurring events such as El Niño and La Niña, as well as a longer-lasting feature called the Interdecadal Pacific Oscillation (IPO), and how these events may be influenced by future climate change.
SEQ is one of the wetter regions in Australia due to its proximity to the world’s most intensive rainfall-band, located in the Western Pacific. The rain-band, which is powered by the warmest ocean surface temperature on the globe, moves eastward during El Nino tending to decrease SEQ rainfall. During La Nina, the rain-band moves westward leading to increased rainfall in SEQ. Many of the wettest years for the region occurred in La Nina years such as 1956, 1971, and 1974.
Much of the regional annual rainfall is recorded in summer. In recent decades, SEQ summer rainfall has been significantly reduced. Up until the drought breaking 2010 La Niña event, the SEQ water storage level dropped to below 20 per cent, the lowest level on record since data collection began in 1890.
The El Niño-La Niña relationship oscillates over several decades, in tandem with the IPO, which has a somewhat similar pattern to the El Niño-La Niña cycle but on a longer time scale.
“Since 1980, the IPO has been in a phase similar to El Niño – limiting the rainfall that La Niña brings to SEQ as a major rain-generating mechanism,” Dr Cai said.
“This is largely responsible for the recent drought.”
As of 2010, the IPO appears to be moving to a phase similar to La Niña.
Taking the average of results from a set of climate models is the most effective way of ‘distilling’ a climate change signal. The science team assessed the role of climate change by using the same 24 models used by the Intergovernmental Panel on Climate Change.
Their results show that the recent drought in SEQ is not consistent with climate change projected by the models.
Funded by the SEQ Urban Water Security Research Alliance, the study’s findings were published recently in the American Meteorological Society’s Journal of Climate.
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Here’s the paper:
Cai, Wenju, Peter van Rensch, Tim Cowan, Arnold Sullivan, 2010: Asymmetry in ENSO Teleconnection with Regional Rainfall, Its Multidecadal Variability, and Impact. J. Climate, 23, 4944–4955.
doi: 10.1175/2010JCLI3501.1
Asymmetry in ENSO Teleconnection with Regional Rainfall, Its Multidecadal Variability, and Impact
Wenju Cai, Peter van Rensch, Tim Cowan, and Arnold Sullivan
CSIRO Marine and Atmospheric Research, Aspendale, Victoria, Australia
Abstract An asymmetry, and its multidecadal variability, in a rainfall teleconnection with the El Niño–Southern Oscillation (ENSO) are described. Further, the breakdown of this relationship since 1980 is offered as a cause for a rainfall reduction in an ENSO-affected region, southeast Queensland (SEQ). There, austral summer rainfall has been declining since around the 1980s, but the associated process is not understood.
It is demonstrated that the rainfall reduction is not simulated by the majority of current climate models forced with anthropogenic forcing factors. Examination shows that ENSO is a rainfall-generating mechanism for the region because of an asymmetry in its impact: the La Niña–rainfall relationship is statistically significant, as SEQ summer rainfall increases with La Niña amplitude; by contrast, the El Niño–induced rainfall reductions do not have a statistically significant relationship with El Niño amplitude. Since 1980, this asymmetry no longer operates, and La Niña events no longer induce a rainfall increase, leading to the observed SEQ rainfall reduction. A similar asymmetric rainfall teleconnection with ENSO Modoki exists and shares the same temporal evolutions.
This breakdown is caused by an eastward shift in the Walker circulation and the convection center near Australia’s east coast, in association with a post-1980 positive phase of the interdecadal Pacific oscillation (IPO). Such a breakdown occurred before 1950, indicating that multidecadal variability alone could potentially be responsible for the recent SEQ rainfall decline. An aggregation of outputs from climate models to distill the impact of climate change suggests that the asymmetry and the breakdown may not be generated by climate change, although most models do not perform well in simulating the ENSO–rainfall teleconnection over the SEQ region.
“Is it due to global warning?”
Can this question ever be answered honestly by someone who has not completely lost all integrity and neglected all good scientific virtues?
My dictionary defines ‘variable’ as ‘changeable’ and thus ‘variability’ (noun) as ‘change’. The same dictionary defines ‘change’ as to ‘undergo a variation’. Hence climate variability IS climate change! I’m reminded of Humpty Dumpty who made words mean whatever he wanted them to mean.
Proof of man made climate change is like hunting elk.
You can hunt elk even when there is no elk although you may not know there are no elk but you cannot shoot an elk, and eat an elk until you have actually found at least one. And if you shoot a rancher’s cow by mistake you still have not found an elk. Also don’t let the rancher or game warden catch you with an elk tag on a cow.
Scientists have looked for man made climate change proof and so far have all the proof of the existence of big foot. It seems to me until absolute proof of the existence of disastrous climate change is found any change in the weather should not be first considered to be the result of climate change. That is like tagging the cow with an elk tag.
I probably used the wrong animal, we know there are elk but and if no one had ever seen one before we would not know it existed until someone produced one and the species would not continue until all the conditions for that were met.
In other words calling harsh weather the result of man made climate change does not make it so anymore than putting an elk tag on a cow meets the requirements of the elk license.
We should be thankful for ranchers and game wardens that can identify mistakes in hunting. And for scientists who do the same in research and reporting.
“Climate change” cannot be the “cause” of anything. A virtually meaningless and void concept such as “climate change” is not a tangible phenomenon, it is a human projection. The same goes for “climate variability”. This can never be the “cause” of anything, even “la Nina” or “el Nino” cannot be the “cause” of anything they happen to coïncide with. I appreciate that it is difficult to phrase meaningfull thesis relating to an ill defined concept such as “climate” which is an inherently variable concept but that is no excuse.
David Stockwell at Niche Modeling evaluated CSIRO’s Drought Exceptional Circumstances Report:
Stockwell, David R.B., 2010. Critique of Drought Models in the Australian Drought Exceptional Circumstances Report (DECR), Energy & Environment, 21:5, 425-436, DOI:10.1260/0958-305X.21.5.425, Link:http://multi-science.metapress.com/content/L4870G0N8Q064377
Stockwell lists further studies showing AGW is wanting.
Discredited AGW
Yes, but I distinctly remember a Senior Australian AGW official saying global warming is unequivocal, and Australia will get drier. Flannery said SE Qld will get drier, but like the weather they can just change their mind, but I do wish they would stop being so certain each time they change it.
Everyone knows that the SEQ Urban Water Security Research Alliance is funded by Big Oil!
/sarc off
Of course the CSIRO had to say that. A couple of years ago they were saying that global warming would bring endless droughts.
Thanks tty and Baa Humbug.
They really must keep their story consistent.
Otherwise, people start asking awkward questions.
If global warming is going to be blamed for anything to do with the Queensland floods in 2011 then perhaps it should be blamed for the 2011 flood series being less extravagant than those of 1974. 1974 was toward the end of a period of cooling.
The Period of “Climate Variability” (transition) can last as long as (or longer than) “Warm Climate”(MWP) and “Cold Climate”(LIA). The transition between “Warm” and “Cold” can be as disruptive (or more so) as the two ‘Titled’ phases themselves. Me thinks we be transitioning now.
http://www.climate4you.com/ClimateAndHistory.htm
Link to the CSIRO report:
http://www.csiro.au/news/SEQ-Drought.html
There is a sentence that is remarkable:
“We found that, unlike in South-West Western Australia, climate change plays little part in the SEQ rainfall reduction, but cannot be ruled out,” Dr Cai said
So in South-Western Australia the drought IS probably related to Global Warming. And last year was the region worst drought on on record:
“Driest year on record for southwest WA”
http://www.bom.gov.au/climate/drought/drought.shtml
On the other side, the recent Queensland floods are almost certain the result of a strong La Niña PLUS a warming trend in Sea Surface Temperatures:
“Annual Australian Climate Statement 2010”
http://www.bom.gov.au/announcements/media_releases/climate/change/20110105.shtml
See the last graph: 2010 Australian SST in 2010 were the warmest on record. With record warm water, there is a lot of evaporation. If the conditions are right (i.e. strong La Niña) this extra water vapor will cause record or near-record flooding.
““We found that, unlike in South-West Western Australia, climate change plays little part in the SEQ rainfall reduction, but cannot be ruled out,” Dr Cai said”
I also found this statment to be rather odd.
Finally! Some summer temperatures in Sydney, Australia. 35c in the city, about 36c out in the west. Australia Day is predicted to be between 36-4c in the West. All being blown out of all proportion in the MSM, and about 5 weeks of “summer” to go.