Guest Post by Willis Eschenbach
Having spent a reasonable amount of time there, I have the highest regard for Australia and Australians. In general they are good, level-headed folks.
Unfortunately, the same can’t be said for the people who wrote the Waxman-Markey website page on Australia. I discussed the first of their “Impact Zones” here, please read it for an overview of the Waxman Markey site. This thread discusses why you need to be very careful with the Waxman Markey “facts” about Australia – they bite.
Figure 1. An Australian example of what we surfers call “the man in the gray suit”.
The website says:
Drought
Global warming is a major contributor to Australian drought. Record high temperatures are increasing evaporation, damaging vegetation and reducing water for irrigation in the continent’s agricultural basin. Sustained high temperatures are as hazardous for people as they are for plants. The average annual death toll from heat waves is over 1,100 people in Australia and that number only stands to increase.
In 2006, Australia experienced its worst drought in the last millennium. The Murray-Darling River System, which produces well over half of the country’s water supply, dropped 54 percent below its record low.
BZZZZT! Bad website, no cookies! Another factual error, and another big lie.
First, the factual error. The website links the claim of the “worst drought in the last millennium” to that noted scientific journal, the Guardian newspaper. It in turn says:
Australia suffers worst drought in 1,000 years
Australia’s blistering summer has only just begun but reservoir levels are dropping fast, crop forecasts have been slashed, and great swaths of the continent are entering what scientists yesterday called a “one in a thousand years drought”.
With many regions in their fifth year of drought, the government yesterday called an emergency water summit in Canberra. The meeting between the prime minister, John Howard, and the leaders of New South Wales, Victoria, South Australia, and Queensland was told that more than half of Australia’s farmland was experiencing drought.
David Dreverman, head of the Murray-Darling river basin commission, said: “This is more typical of a one in a 1,000-year drought, or possibly even drier, than it is of a one in 100-year event.”
What’s wrong with their statement? A number of things. First, “scientists” didn’t say anything about a one in a thousand year drought. That was said by David Dreverman, who is the head of the local Murray-Darling river commission.
Second, Mr. Dreverman did not base that statement on a thousand years of drought records preserved in tree rings, or on other proxies, or on any observations at all. It was simply a mathematical estimate of what is called a “return period” based on a probability distribution, not a scientific statement of historical fact. Here is a link (PDF) to how it was calculated.
Third, his statement was only peripherally connected to the drought. He was actually talking, not about the drought, but about the return period of the flow of the Murray River.
Fourth, he either didn’t notice or didn’t want to comment on the other reasons why the Murray River is so low. Here (PDF) are some of the reasons:
So why is there less water?
The amount of water that ends up in the Murray river has changed because:
• More farm dams have reduced run-off by between 660 and 2,400 gigalitres (Gl) per year
• Groundwater pumping has reduced run-off by 327 gigalitres per year
• regrowth from the bushfires in early 2003, when over a million hectares of
native forest was burnt, could reduce run-off by 430 gigalitres by 2020
• new plantations could have further reduced inflows by 1,100-1,400 gigalitres per year
• farmers have increased the water holding capacity of their soil by adopting minimum tillage.
So that’s the factual error. The 2006 drought was serious, there’s no question about that. But there is no scientific evidence that it was the biggest drought in a thousand years. That’s just alarmist hype.
If that’s the factual error, where’s the big lie?
The big lie is that global warming is making Australia drier. Or as the website says:
Global warming is a major contributor to Australian drought. Record high temperatures are … reducing water for irrigation in the continent’s agricultural basin.
Why is that a big lie? Because Australia has has been getting wetter as the globe warmed over the last century.
How do I know that? Well, that’s what the Australian Bureau of Meteorology says. Here’s their information about Australian rainfall, from their website.
Figure 2. Changes in rainfall, Australia, 1900-2009
No sign of a problem there, rainfall is increasing. It has increased by about 80 mm (3″) over the last century. Note that (as has been true for millennia), the rainfall in Australia comes in fits and starts. It is not uncommon for a year to have twice the rain of an adjacent year.
Now I can hear you thinking “But what about the places that were hit by the drought? The Murray-Darling River basin (of “1,000 year drought” fame) and West Australia and South Australia were all hit very hard in 2006. They must be drying out.”
We are nothing if not a full service website:
Figure 3. Changes in rainfall, Murray Darling Basin
Figure 4. Changes in rainfall, South Australia.
Figure 5. Changes in rainfall, West Australia.
No reduction in rainfall there either. Yes, there was very little rainfall in 2006 in South Australia and the Murray Darling Basin and West Australia … but in all cases, there have been worse years in the historical record.
Finally, there must be some areas of Australia that are getting dryer, aren’t there? Of course. It’s a big place. Here’s an overview of the country, showing the changes since 1900:
The overwhelming majority of the country has gotten wetter. A few places have dried slightly.
SUMMARY: Their web page contains one misrepresentation of fact about droughts, and one big lie.
Misrepresentation of fact: the 2006 drought was not the biggest in a thousand years. Most places it was not even the biggest drought in the historical record.
THE BIG LIE: When you look at the full record for Australia, it is evident that as the globe warms, Australia is not drying out. It is getting wetter.
The big lie is that “global warming” is reducing the rainfall in Australia. In fact, it is increasing the rainfall … go figure.
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Comprehensive debunking of some utter rubbish – well done Willis! W-M ought to be ashamed of themselves for peddling such ill-informed bullsh!t.
You have to look at the weather from the perspective of the University educated activists of today, if it hasn’t been on television, it hasn’t happened. In 1956 we could walk across the Murray at Echuca, in mid-May 1968 , Melbourne had less than a months supply of water, Droughts and floods.
The front page story in this morning’s (01 July) Adelaide Advertiser states:
“INTERSTATE farmers have diverted enough floodwater to private dams from the Murray-Darling floodplain to more than fill the dying Lower Lakes.” http://www.adelaidenow.com.au/
The lack of June rainfall in Adelaide had been the subject of most weather forecasts in the nightly news until rain on the 30th pushed us over the June average (no mention of what period the ‘average’ referred to).
The comment then changed from “we are still below the June average” to “we are still below the 6 month average”.
It seems that, unless we receive the ‘average’ of some metric, there must be a problem and it MUST be caused by us dastardly humans.
Baa Humbug – I’m not sure why when describing two opposing scientific papers you feel the need to question the motives of one and not the other. In any case, that a strong drought would be correlated with increased sunshine is almost self-evident. What matters is the long-term trend. Interestingly, the decrease in pan-evaporation over Australia (pan evap over the MDB has increased) some have noted has been attributed to _decreasing_ sunlight due to increased cloud cover and aerosol loading by by Roderick & Farquar, Science, 2002. I’m not fully convinced of this, however, the decrease in sunlight has been observed elsewhere and may be some reason for the skepticism of the claims of the Lockhart paper you cite.
Additionally, the trend in mean evaporation is less important than the trend in evaporation under dry, drought conditions. There is some evidence (as Baa Humbug cited) that, at least for 2002, the evaporation was higher in the MDB that other similar periods.
That a drought in a higher background temperature, all else being equal, is worse than one in in which the temperature is not elevated doesn’t appear to be all that controversial to me. Although I would again object to it being a ‘major contributor’. Attributing this sort of thing to greenhouse gases (or aerosols or anything else) is another matter, although people do try.
Dave Springer – there must be a global balance between rainfall and evaporation, not necessarily at local or even continental level. The point I am making is that given the same circulation conditions in a drought, the higher temperature one will be “worse”. There is also a lot of modelling and theoretical work that suggests a warmed world would have an increased (in magnitude) value of evap – precip in most regions (see Held & Soden 2006, Journal of Climate, Held & Soden 2000, Ann. Rev. Energy and the Environment). That is, the circulation changes will tend to make the subtropics dryer. I know those that frequent this website like obs rather than models, but they are nice papers nonetheless.
Anthony, don’t worry about being blamed for the cold weather down here Down Under. We Aussies figured out long ago that it is due to Al Gore.
Never let a good crisis, true or false, go to waste.
I thought the scientists figured out that the monsoons in the Indian Ocean were responsible for most of the changes.
http://earthobservatory.nasa.gov/IOTD/view.php?id=43673
Carl Chapman says: June 29, 2010 at 11:09 pm
The rule is simple: if a country has low rainfall then Global Warming will make it worse with less rain; if a country has high rainfall then Global Warming will make it worse with m[o]re rain. If you run the models enough times, you can pick whatever answer you want for each country.
Succinct and accurate. Well done for a first post.
Marty Singh says:June 30, 2010 at 8:32 pm
Baa Humbug – I’m not sure why when describing two opposing scientific papers you feel the need to question the motives of one and not the other. In any case, that a strong drought would be correlated with increased sunshine is almost self-evident.
Gee, I thought wet and dry periods were correlated with precipitation . And precipitation was associated with atsmospheric humidity. And atsmospheric humidity was associated with evaporation from water surfaces. And the biggest water surfaces are oceanic. And the surface temp of the water is associated with increased evaporation. And the surface temp in that area is collectively called the SOI, which is associated with wet and dry periods. But silly me.
Total grain production from Australia :
2001/2002 – 38.01 mmt (best evah record at that date)
http://www.fas.usda.gov/wap/circular/2003/03-02/wldsum.pdf
02/03 – 17.08 mmt
03/04 – 41.42 mmt (best evah record)
http://www.fas.usda.gov/wap/circular/2005/05-01/WldSum.pdf
04/05 – 35.42 mmt
05/06 – 32.87 mmt
http://www.fas.usda.gov/wap/circular/2005/05-09/WldSum.pdf
07/08 – 25.4 mmt
08/09 – 33.7 mmt
http://www.fas.usda.gov/wap/circular/2009/09-05/productionfull05-09.pdf
2009/2010 34.2 mmt
http://www.fas.usda.gov/wap/circular/2010/10-06/production_full06-10.pdf
Australian wheat production 1998-2008:
03/04 – 26 mmt (best evah record)
9 years above 20 mmt; 2 years bad crops 02/02 – 8.86 mmt, 03/04 14.81 mmt
http://www.fas.usda.gov/wap/circular/2007/07-09/wapfull0907.pdf
Where the heck is this massive drought, alledged increased evapotranspiration, doom and gloom, etc., etc., show up in the data? Good crops getting better, with a few drought years inbetween. The bad years only reduced exports. The Aussies will adapt and survive as they have before, if the government doesn’t take capital away from the innovative private sector to build Don Quixote amalgamations.
Tim Clark – droughts are periods of low rainfall. To the extent that clouds are correlated with rainfall this is also a period of low average cloud cover, and hence high sunshine. Obviously drought is also correlated with precipitation as you state. Precip also has a relationship (although more complicated in the mid-latitudes than the tropics) with atmospheric humidity. In the subtropics/mid-latitudes total column humidity doesn’t really have a very tight relationship with evaporation, as most of the water vapour is advected into the column rather than evaporated from the surface beneath. The SOI is a measure of the pressure differential between Darwin and Tahiti. The sea surface temperature indicies related to ENSO are the ‘Nino’ indicies (there are a few) which mostly measure Eastern pacific sea surface temperature. The effect of El-nino on Australian rainfall is a remote effect and is not simply due to warmer water having the ability to contain more water vapour.
Desptie all that, you do have one thing right – rainfall in Australia has a strong relationship with ENSO. The question I was addressing was really about whether a given drought (related to El-nino, IOD, or anything else) might be worsened by a warmer background state.
Since you mention it however, a lot of the IPCC models predict a more ‘El-nino’ like state of the pacific in the late 21st century given increasing greenhouse emissions. I was rather sceptical of this result, as models have a hard time simulating a decent El-nino at all. However, the Held & Soden 2006 paper I already mentioned has a very interesting take on why the models might produce a weakening Walker circulation, which gives a little more confidence that the result is not too dependent on the complex dynamics of El-nino itself. Still, I’m not betting my house on it just yet.
Marty Singh says: July 1, 2010 at 5:14 pm
Desptie all that, you do have one thing right – rainfall in Australia has a strong relationship with ENSO. The question I was addressing was really about whether a given drought (related to El-nino, IOD, or anything else) might be worsened by a warmer background state.
Since you mention it however, a lot of the IPCC models predict a more ‘El-nino’ like state of the pacific in the late 21st century given increasing greenhouse emissions. I was rather sceptical of this result, as models have a hard time simulating a decent El-nino at all.
And the point I was making is that warmer global average temperatures are highly associated (1997-8, 2009-10)) with a positive El Nino. A positive El Nino is highly associated with increasing precipitation in many areas, namely S. Cal, Az, Co. Ks. Nm and parts of other us states and portions of Aus as moderated by the SOI. And specifically, under these conditions, higher temperature in Australia would generally occur in combination with increased precipitation. We both probably do not have time to correlate the absolute temperature – precip relationship that occurred during the recent drought in Aus. But I would be interested in seeing it.
But consider that plants do not transpire much above a certain temperature, about 92F for c-3 plants, and plant response to any absolute temperature above about 95 F is subject to exponential diminishing damage from heat alone, provided sufficent moisture is available. So in regards to a warmer environmental equilibrium, the plant doesn’t care much if the temperature is 95 or 105. It’s also critically important at what stage of growth this occurs. Also, under dessicating conditions, more damage can be done by wind that by drought. Plants are more damaged by elevated nightime absolute temperature inhibiting dark respiration than by absolute daytime temp, if sufficient water is available. I believe it’s more complicated than just saying that warmer initial conditions would increase drought severity. It depends on what the normal is relative to warmer, nightime temps, and whether the wind blows more during an Aus drought.
Tim Clark says:
July 2, 2010 at 8:37 am
Tim, thanks for the comments. Being the naturally skeptical SOB that I am, I thought I’d check your claim. El Niño/La Niña are defined as a temperature excursion of greater than 0.4°C in the El Niño 3.4 area (5S-5N, 170W-120W). Here is that long-term record, along with the running average for both conditions:
I don’t see a whole lot of correlation between El Niño and global temperatures. It seems to be correlated with the PDO, but not with the global temperatures.