Climate Witness: Derek Newton, Australia
My family has always maintained detailed weather records and I am a keen observer of the weather and climate.
The major change to the climate we’ve noticed is a change in the pattern of rainfall.
The average amount of rain has not changed considerably but the way in which it falls has changed. There are fewer wet days with longer periods of dry weather between the wet periods. The wet periods are shorter and more intense. Just as the country is getting wet and is about to run water, the rain stops and the following long dry period allows the country to dry out again. We haven’t had a good wet period since the early 1990’s. In this country, from a perspective of pasture growth and runoff, if we don’t get a good wet spring we start the summer dry and never seem to catch up. From 1990 until last year we have had dry springs and the winters have been getting drier.
We built our irrigation dam in 1984 and from then until 1994 it was mostly full and frequently over flowing. When we put that dam in we thought we would use another dam near the house as a supplementary dam, just in case. Now we rely on our supplementary dam almost 100 percent – it has a very big water collection area and we’re just not getting the runoff to fill the irrigation dam.
Until last year we have had a steady decline in the number of frosts recorded. The lowest temperature for the winter is about average but the winters, overall, are getting milder. This winter is a good example we have only had a few frosts and the apricots are moving now, in July!
These changes have had a number of impacts on our operations here. The stocking rates on Bendee have declined by about 1000 dry stock equivalent. There is more regrowth, part of that is because there are not enough sheep to keep the regrowth down. Until the 1990s we used to breed here. After that it just became uneconomic to breed – inconsistent seasons result in lowered reproductive rates. We now lease out the sheep area and concentrate on the orchard.
We haven’t had a good wet period since the 1990s.
From 1990 until last year we have had dry springs and the winters have been getting drier. In the 1990s we used to breed sheep here. We now lease out the sheep area and concentrate on the orchard. We’ve changed from being woolgrowers to orchardists.
Trial and error to deal with the drought
In the orchard we have had to totally change our irrigation management to deal with the longer dry periods. The trees struggle for moisture with long periods of no rain, so we are now using more drippers per tree and attempting to wet a larger area with each watering. We are using more frequent waterings and now irrigate almost all the time during summer. Rain is best for the trees and when it doesn’t happen we have to simulate it in the best way we can.
We are also using mulch under the trees. We have grassed up between the trees and use a side delivery mower to throw the mowings under the trees. We mulch the prunings and put the mulch under the trees. The grass and the mulched prunings the under the trees conserve moisture and also help to control weeds without using chemicals.
Over the last 15 years we have changed from being wool growers to orchardists and that has required a lot of research and trial and error. I get my information from reading, from attending workshops and talking to neighbours. Rural people are generous with their knowledge.
I farm because I enjoy it. It gives me a lot of satisfaction. I was born here and I know this country very well, I only wish it would pay the bills. The winters, overall, are getting milder. This winter is a good example – we have only had a few frosts and the apricots are moving now – in July!
Scientific reviewReviewed by: Dr Barrie Pittock, CSIRO Marine and Atmospheric Research, Australia
Derek describes the impact of prolonged drought in south-eastern Queensland on his agricultural business. His story is consistent with events generally for southeast Queensland up to the 2007-8 summer, but it has been wet in the area this summer.
The situation is that there has been a long-term drying trend probably due to global warming, but this is interrupted by natural variability mainly due to the El Nino-Southern Oscillation phenomenon. This alternates between dry El Nino years and wetter La Nina years. 2007-8 has so far been a wetter La Nina time in Stan’s area.
The generally warmer conditions means that the dry times have tended to be drier due to greater evaporation, and that has made droughts worse.
Pittock, A.B., 2007: The Enhanced Greenhouse Effect: Threats to Australia’s Water Resources, Part 1: Scenarios for the Future, Water (Journal of the Australian Water Association), June 2007, pp.48-54.
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