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:
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.