When it comes to rainfall, south-west Western Australia has been hit by climate change harder than almost anywhere on earth, according to climatologist Pandora Hope from the Bureau of Meteorology.
- South-west WA has seen a 20 per cent reduction in winter rain since 1970
- The declining rainfall has seen up to 80 per cent declines in runoff into dams
- Farmers are adapting to the changing conditions, shifting from livestock to crops as needed
“South-west Western Australia was very much one of the first places to really see the shift that we expect with global warming, so it’s had one of the biggest changes compared to many places in the world,” she said.
Pandora Hope said there had been about a 16 per cent decline in the region’s rainfall since 1970.
“But if you look at the cool season — so winter through spring — the declines are in the order of 20 per cent,” she said.
“And if you actually look since about 2000, those declines intensify to about 30 per cent.”
Farmers adapt to dry
From drinking water to bushfires, few parts of life in the west have been left untouched by a drying and warming climate — and the south-west region’s farmers are adapting.
The summer in Varley, a community four-and-a-half hours drive east of Perth, is typically dry, but Ms Newman can’t recall a time when it was looking quite so parched.
“This is our third dry summer, and they incrementally build on each other,” she said.
“So at this point, now most of our dams are dry.”
Streamflow to decline
Streamflow and runoff into dams are extremely sensitive to reductions in rainfall, according to the West Australian Department of Primary Industry, which predicts median streamflow to decline by nearly a quarter in the south-west by 2030.
This comes on top of huge declines in runoff over the past 50 years.
“Since the 1970s, we’ve had a 20 per cent reduction in rainfall in this part of the state,” said Tom Hatton, the former Chair of WA’s Environmental Protection Agency.
“Now, that doesn’t sound like a lot, but it results in an 80 per cent reduction in streamflow. So, in the past (with) the catchments around Perth we could rely on something like 400 gigalitres of water a year to be replenished.
“Now we’re lucky if we get 70 gigalitres and we don’t even rely on that.”
For sheep and cropping farmers like Anna-Lisa Newman, dry dams mean difficult decisions.
“We’re not at the critical stage of, say, east coast farmers where you can gradually reduce your flock and then have to step away altogether,” she said.
“We’re not near that point.
The dry years also provide an opportunity to adapt.
“Going forward, on the cropping side of things, we’ve really advanced in our ability to maximise returns for the lower rainfall that we can get,” Ms Newman said.
“So I’d like to think we could do something like that with our stock. And I think there’s technology in terms of desalination.”
Despite the challenges posed by a drying climate, the changes are bringing opportunity as well. Many areas of Western Australia once considered too wet for cropping, are now major producers of grain.
From livestock to crops
Tim Tresize, a farmer from Jingalup in the south-west, said when he first moved to the district 20 years ago, it was a very different place.
“You would drive around and mainly see pasture and sheep and cattle whereas now when you drive around you mostly see crop,” he said.
Mr Tresize said economics also played a big part in the shift.
“Sheep weren’t going that well, so people dabbled in cropping,” he said.
“And they started getting good at it and getting some success. So they’ve run with it.”
Mr Tresize said the last four dry seasons have been good for them.
“That’s when we have really good production years because water-logging costs us a lot of money in a wet season,” he said.
With projections rainfall will continue to decline, Mr Trezise is backing farmers to adjust.
“They just sort problems out and they keep going,” he said.
“So, you know, I back a farmer every day of the week … to adapt and get on with it.”