As reported in The Age http://www.theage.com.au/news/national/a-onein1000year-drought/2006/11/07/1162661662965.html the Murray Darling Basin Commissioner, Wendy Craik,or perhaps someone else, says that current drought is the worst in 1,000 years.

How would they know? They didn't have rain gauges 1,000 years ago http://en.wikipedia.org/wiki/Rain_gauge and although the Greeks were measuring rain fall in 500 BC, it's a pretty sure bet that Australian aborigines weren't, or if they were didn't pass the records on.

This headline and story is typical of the alarmism and plain stupidity being pedalled as fact about climate by bodies anxious to escape any blame for not preparing for an entirely predictable occurrence. Yesterday I heard Mike Young (no relation) from the Wentworth Group tell Fran Kelly http://www.abc.net.au/rn/breakfast/stories/2006/1781870.htm that what we are experiencing is a "step change" back to the rainfall of the 40s and 50s.

At least he's making a point about the cyclic nature of weather, but how does he know it is a "step change" (whatever that means)? It's only 50 years back to the 50s (it's not that long ago, think Chuck Berry and "Rollover Beethoven" for example), so why wouldn't you say it was just a part of the cycle?

In the development industry we are asked to plan for once-in-a-hundred year occurrences. I've often wondered how we'd know what a once-in-a-hundred year occurrence was, because with only around one hundred years of records, our sample is too small to make a statistical assessment of the frequency of weather events.

But statistical rigour appears to be the last thing that the "experts" are worried about.

GrahamY,

How would they know indeed! I am not expert in the field, but one means of determining this may be with the aid of dendrochronological studies (tree ring growth records). I have seen no reference to this field made in support of climatic variation claims. Of course, the studies would have to relate to different regions throughout Australia to be definitive, but such could provide some insight.

An interesting aspect of dendrochronology, at least so far as Tasmania is concerned, is the peculiar characteristic of Huon pine, which contains a natural preservative. Apparently, tree ring sequences going back thousands, even tens of thousands, of years have been compiled. One would have thought that such studies would have been advanced at the forefront of this 'debate'. Whether in former millenia Huon pine grew on the offshore island of Australia, and if it did, whether any fallen log sequences lie buried in swamp or riverside locations, I do not know. But someone might.

More worrying to me is the fact that the last time I heard the term "step change" used in public discussion was in July 1987. It was used in relation to the sudden change in the election count trends on election night after there had been an interruption to the operation of TENIS (the election night information system) operated by the Australian Electoral Commission. Malcolm Mackerras had made a prediction on the basis of the early trends of a Coalition victory. Then there was the computer failure. Then there occurred the reversal of the trend. Malcolm got egg on his face. There had been a "step change" in the data. There was significant public comment by professional statisticians in following days. No definitive conclusion was reached.

Could all this "alarmism and plain stupidity" be nothing more than a backdrop being set in place to make believable dramatic changes in voting patterns at upcoming elections in Australia, and perhaps elsewhere? Dendrochronologists! To the front, quick march!

the structure of our political society precludes longterm planning. if environmental questions force themselves onto the agenda, these questions will be dealt with by buckpassing and ad hoc 'solutions'.

it is very amusing to watch politicians attempting to survive and prosper in situations they are utterly unfit to cope with, but dont laugh too loud- it's your nation they are buggering up. i say 'your' in the relational sense, as a sheep to it's paddock. in the possessive sense, it's not yours at all, it's theirs.

since australians are a subject race, unable to direct the destiny of their nation, or even conceive of the utility of doing so, all discussion of this question, and every other, will in the end be no more than "somebody (else) should do something."

Calling the current lack of water a 1000 year drought assumes that normal rainfall will resume some time soon. In the last 60 years we have changed the face of Australia by

- deforestation eg in 1939 95% of Victoria was forested

- hydroelectricity, irrigation and flood mitigation schemes

- syphoning Darling River water into Cubby station.

In primary school we all learnt the rain cycle of
- water vapour forms over the ocean
- moves over land and collects more water vapour from the CO2 given off by the trees
- moves over the mountians and falls as rain.

In the last 60 years the population has trebled, houses have got bigger and each dwelling houses less people - so the land devoted to housing might be 10 times as much as 60 years ago.

Urban areas are warmer than rural areas. Rain forests are 5 degrees cooler than cleared farmland.

By deforestation and urbanisation we have made Australia hotter and drier.

We, the Australian people - not the market - need to decide what crops need to be grown under irrigation, which land should be taken out of agriculture and do it fast.

Forrest, my understanding is that reconstructions of climate using cores in the Great Barrier Reef suggest that we have seen worse droughts before we Anglos settled here than since. Not that this provides evidence of what may have happened in the Murray Darling.

But you don't have to go back that far to check the MDBC claims. Jennifer Marohasy has kindly placed a graph on her site using Bureau of Meteorology figures which show Murray River flows haven't changed too much in the last 100 years, and in fact on a rolling average appear to have been trending upwards. You can view the whole of her post at http://www.jennifermarohasy.com/blog/archives/001719.html

What I can't understand is why journalists, who are normally quick to sniff a conspiracy, have lost their sense of smell on this one.

Graham_Y are you suggesting the the shortage of water in the Murray_Darling Basin isn't so much attributable to drier weather but more to increased irrigation extracting more water from the system?

Does this mean we really do have to compulsorily acquire Cubby Station, and ban rice and cotton farming in the Murray-Darling?

Or do we decide to allow our dairy product, orchard fruit and market garden vegtables to be imported from New Zealand, China and Thailand.

The body language of the Victorian minister for the Environment standing behind the Premier suggested he was not happy

Hi Billie

As regards irrigation. Well not many rice or cotton growers will be planting this year. They have very low or zero water allocations.
Much of the hand wringing is because farmers with perennial crops, eg. wine grapes, need and expect a water allocation every year. They use less water but have what is called a 'higher security allocation'. Indeed during this drought South Australia has been receiving fully 80 percent of its total water allocation because most of the perennial crop are down there ... while upstream farmers have gone without.

It begs the question why do some many academics promote wine grape growing and campaign against rice... when in a land of 'drought and floods' it is better to just grow crops when there is water and perhaps let rivers run dry when there is drought?

On the issue of this being a one in 100 or 1,000 year event. Well the rainfall record for the MDB doesn't support such a proposition. But inflows have been very low. Here are some possible reasons why:
salt interception schemes evaporating water, drainage management plans designed to keep water tables low artificially dehydrating the landscape, more plantation, more regrowth in the top of the catchment from the January 2003 bushfires, more water recycling ... and also the low rainfall

Here's a link to the presentation at the summit by the MDBC and the guy who apparently suggested this was a 1 in 1,000 year event: http://www.mdbc.gov.au/__data/page/54/First_Ministers_Briefing_7Nov06_MDBC.pdf .
There is no mention in the presentation of this being a 1 in 1,000 year event.
But have a look at how he slips from discussion of low rainfall to discussion of low inflows! Its potentially very misleading. They are different issues.
Clearly the MDB has a low inflow problem. Clearly there is a need for an audit of the different factors that may have contributed to this.

In relation to the MDB, this year has been exceptionally dry. Why don’t you look at this graph from the BOM http://www.bom.gov.au/cgi-bin/silo/rain_maps.cgi which shows the rainfall anomalies for the past 9 months. The chart given by Jennifer does not show 2006 data. You can see that the Snowy Mountains and the SW slopes of NSW, both major feeders of the Murray have recorded their lowest rainfall on record. Low rain means low inflow. The low rainfall was caused by a lack of cold fronts intruding into Victoria and NSW, thanks largely to blocking high pressure ridges in the Tasman Sea.

So, a one in a hundred year drought? Yes. One in a 1000? We don’t know

GrahamY,

To suggest the direction in which an answer may be found to your puzzlement as to the ' loss of journalistic sense of smell' in reporting on the great climate change debate. (I'll use the word 'debate', although I am sorely tempted to use the term 'beat up'.)

Is it too much to suggest that we in Australia are in a situation where the resources of this country (and I specifically exclude the human ones) are seen as being of relative significance in a major realigning of energy and environmental impact policy in the US and EU? Given this significance, are we nationwide being subjected at every level to an already agreed upon editorial line from the top down, an editorial line of assertion of the fact of climate change? Would not this international editorial line be capable of being especially well tailored to the shibboleths and articles of faith of Australian politics, as well as the natural sensitivity of Australians to the vagaries of climate, by a native born expert on the Australian scene?

With a line already determined in some detail, and the 'science' selectively harnessed ready in its cause, would it not be easy to assign truly competent journalists to backwater issues, and weed out run-of-the-mill journalists seen to be deviating from the predetermined line before any reporting of significance is done? This may not be a case of the media reporting the issue as it develops, this could be the media deciding what is the issue and reporting it accordingly.

If I'm right about overseas perceptions as to the significance of Australian resources in this policy realignment, it will be desirable to those interests to maintain a relatively weak and distracted national government in Australia. To do this they may need a new political presence in Canberra. I think they have rightly assessed a genuine public concern with respect to sustainability issues, and are simply building credibility for a change that may be already within their power to realize electorally. That way, when the change happens, we'll all believe it.

Hi Jennifer, the presentation talked about the Murray River system, and I always thought that the system was the Murray Darling system.

I note your comment about the lack of information on inflows and as an ignorant layperson note that Cubby Station is at the top of the Darling River so although it has a licence for 25% of Queenslands water, this could translate to 5% of the MurrayDarling irrigation allocation.

Part of the complaint about cotton is the amount of chemicals sprayed on the crop and suggest that cotton really ought to be grown in Kunnunura.

Misunderstanding about the cotton industry is widespread and ingrained. Cotton farmers tend to be very efficient water users, constantly seeking to keep their water efficiencies as high as possible. Water is a large part of their production costs, and as such most have complex recycling systems and experiment with different methods of water delivery and water use by plants. Yes they have a relatively high incidence of sprays on conventially grown cotton. However GM cotton seeks to reduce the number of insecticide sprays and also to simplify the weed spraying process. Roundup Ready cotton is resistant to the use of roundup herbicide (the glyphosate chemical that you use at home for spraying your garden edges), so this can be sprayed to combat weed compitition, rather than using more complex and expensive chemicals. INsecticides are the nasties that most people have a problem with. However it seems that the same people are against GM cotton, which seeks to reduce the requirement for insect sprays by gene manipulation. Other methods of insect control include shelter wheat, where a twin row wheat crop is planted on top of the furrows, and then sprayed out when the stubble reaches a certain height. Cotton is then planted in the middle of the twin rows and the wheat acts as a shield against insects until the cotton reaches the top of the wheat. I have seen it save up to 5 insect sprays.

Note that cotton is a very expensive crop to grow, so the cotton industry has had to be at the forefront of farming technology. Most of the technology and methods developed by cotton farmers eventually flow onto other farming sectors, who dont have as much at risk as cotton farmers, so tend not to invest as much in research as the cotton industry.

Country Gal, the other "villain" is rice, and it does seem to me as a layman that anything requiring that level of water shouldn't be grown in a dry country like Australia. However, I heard Graham Blight http://www.google.com.au/search?sourceid=navclient&ie=UTF-8&rls=GGLG,GGLG:2005-33,GGLG:en&q=graham+blight on radio yesterday suggesting that rice is the most efficient converter of water into carbohydrate.

If that's true, and I'd love someone to give me some information on that, then growing rice probably isn't a stupid thing to do at all.

Is there a comparable efficiency argument about cotton?

Billie, I don't have a problem with Cubby having 25% of the Queensland allocation (if that is what it is), because they presumably had to buy it from someone else who put less value on the water. If Cubby goes broke or scales down (and you'd have to wonder about how it is travelling given its dam is all but empty), then that water will presumably be purchased by someone else.

http://www.ancid.org.au/pdf/mildura_pdfs/DriversinWaterValue/NihalJayawardane_ancid.pdf

The tables in this research paper show a comparison of the efficiencies of various food crops, both in yields and water usage. Rice is on the higher end of the water usage scale, and uses much more irrigation water, but this is because it has to be grown in areas of Australia that are winter-rain based. The winter rain (and snow melt) is collected and then used in the irrigation of these summer crops. Evaporation rates are higher as the crop is a summer crop, and thus more heat = more evaporation. However, rice is a very high yield crop and thus despite its high mg/ha count, its tonne/ml count is quite reasonable. Whats more the soils in the vast majority of the rice growing areas are more suited to rice growing than other types of crops.In the above paper it shows that barley is a very efficient water user. However barley needs a certain type of soil to perform well, as does rice.

There are no water-carb production details for cotton, as it is a fibre crop, not a food crop. Cotton is pretty unique in that it has no commercial cropped competitor (its competitors are wool and nylon - grazed and manufactured). Cotton is a crop that has more than one use. The fibre itself is used for clothing, the seed (seperated from the fibre at harvest) is used for cottonseed oil (cooking) and cottonseed meal (stock feed) and the plant remains are ploughed back in as compost to improve soil nutrients and structure

As for water use, cotton is a desert plant. However to produce well it needs a regular water supply. Its does better under irrigation methods than grown in wet climates. This is because too much moisture in the plant structure and around the plant leads to boll rot (the boll is the part of the plant holding the cotton). When boll rot occurs the cotton is rotten and yield destroyed. Cotton grown in argentina (for example) faces this problem of boll rot. They have enough rainfall to grow the crop without irrigation, but lose a large percentage to rot, particularly if the rain falls at the wrong time of the season (when the bolls are developing). Northern NSW and southern QLD are good cotton growing areas, as they have the daily heat requirements to eoncourage good growth, and whilst they are subject to summer storms (which helps reduce irrigation requirements), the storms are not often enough ro large enough to give a large risk of boll rot. The soils of these areas are also well suited to cotton requirements.

Therein lies the difficulty in farming in australia. We have very few areas where we have all 3 requirements (soil, climate and water). So the solution so far has been to find the right soil and climate for a particular crop and try to get the water to where it is needed.

I dont think that the answer is to stop farming here. Climate change may be happening and may end up having a huge effect on farming in this country. I am suspect of this though, as I grew up in a rice growing area where rising water tables were the evil of the day. Now we find that perhaps too much effort has gone into trying to lower these water tables, with the result that the land is drying out too much. Science at the moment is doing a pretty big backflip on this one, and on other environmental issues.