Queensland’s Premier, Peter Beattie, has been telling the 2 million or so people who live in the south east of Queensland that “we have a water crisis and the worst drought on record”.
We are dependent on three dams to the north-west of the city of Brisbane and it has not rained in that catchment for some time. But is it the worst drought on record?
Most reporters have just been repeating the Premier’s claims that it is the worst drought on record; which in Australia only takes us back a hundred or so years.
But this morning there was a piece in local paper the Courier Mail explaining that: “a computer simulation showed if the Wivenhoe and Somerset dams had been built earlier this century they would have been empty during the federation drought and close to current levels in the 1940s. …hit low levels in the 1920s, late 1980s and late 1990s.”
William Kinnimonth in a piece for the IPA titled ‘Predictions of Drought Lack Credibility’ writing last June, in a whole of Australia context, identified the following drought years:
1885-1902 (the federation drought)
1914-15*
1937-45
1965-68
1982-83*
1991-95.
Kinnimonth links all of these droughts to either major El Nino events (1914-15 & 192-83) or to years when their was “El Nino-like sea surface temperature patterns across the equatorial Pacific Ocean” (those years not marked with an asterisk).
There is much speculation that the Premier will announce an early election for perhaps 9th September and make water a feature of his re-election campaign. This is perhaps a risky strategy as he is perhaps responsible for the ‘water crisis’ in so much as his government has invested very little in water infrastructure over the years. Alternativley he could hope it storms over summer? He doesn’t have to hold an election until February.
Is it likely to rain this summer potentially taking the pressure off south east Queensland water supplies?
My reading of the following advice from the Bureau of Meteorology is ‘perhaps’:
“The overall ENSO status remains neutral. Generally weak trends have been observed in the main Pacific climate indicators during the past few weeks, and the potential for an El Niño event to develop this year is still relatively low. … The main concern remains the Southern Oscillation Index (SOI), which is still hovering around the −10 mark, indicating a general weakness in the Pacific Walker Circulation. In addition, the Trade Winds have been weaker than average across much of the Pacific during July, so this situation will be monitored closely for any sustained trends. However, with the exception of the far eastern Pacific, ocean temperatures are only marginally above average, both on and below the surface. Therefore, there is only a slight risk that the Pacific will warm to levels high enough for an El Niño event to develop.”
Given the importance of ocean temperatures as a driver of weather and climate it is interesting that climatologists don’t have a better understanding of how it all works. There is an interesting article titled ‘El Niño and Global Warming’ at www.realclimate.org exploring some of these issues.
But tell me, will it rain this summer in south east Queensland?
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
Simple. It will rain more than enough to fill a decent sized water tank but is unlikely to fall in events of more than 100mm each and consequently, no water will make it to the dams.
Curiously, the map that was shown to indicate prolonged rainfall deficit in southern Queensland failed to show those parts of Brisbane that have had above average rainfall for the past 12 months. I guess this data has been “smoothed” as the current scientific standard allows and condones.
But there is one element of good news in all this. When rainfall is bad for dams and the people who are silly enough to rely on them, it is good for vegetation and the wildlife who depend on it.
The worst years for biodiversity are those with major rainfall events which fill dams because they are then followed by 2 or 3 month dry spells that kill off the newly emerged young.
The best years can actually have below average falls but have a lot of small events that keep the soil moisture profiles topped up and vegetation continually growing. These are the only years that get the adolescents right through to adulthood.
And ironically, the years that are good for wildlife are also good for farmers for the same reasons. Another instance of the urban community being out of step with nature.
Actually.. climate change pundits predict more weather “events” such as storms and storms can fill dams more than gentle soaking rain ever could.
So climate change is good for dams oui?
Today in the Courier Mail I’m suggesting desal and recycling so a crisis can be averted whether it rains or not: http://www.news.com.au/couriermail/story/0,23739,20061298-27197,00.html .
But noting Ian’s comments here and at other threads I will write something on water tanks down the track.
The problem with the desal and some of the recycling options is that they are concieved as short term fixes but once in place must remain fully operational to cover their capital costs.
And that means that when the dams are full again there will be less sales from them to cover their overheads.
Instead of the big ticket items they should simply be increasing extractions from the aquifer projects because these can be depleted in the short term to be replenished in later wet years.