How climate change is affecting what we grow and eat

Updated

Farmers and scientists are finding new ways to keep food on the table as rainfall patterns move and heatwaves increase.

Longreach grazier Peter Whip runs cattle on country that neighbours the desert.

The climate there has always been variable. Dry times are a familiar foe and big variations in rainfall are all too common.

That makes it hard to pinpoint how climate change is directly affecting him.

But there is one measurement that illustrates it all too well — days over 35 degrees Celsius.

"There's a noticeable increase in days over 35," Mr Whip says.

"And the reason that's important is because once you get over 35 degrees, that's when the temperature starts to make an impact on cattle."

At that temperature cattle don't want to eat as much. By 40 degrees, their intake of dry matter can drop by up to 50 per cent.

Mr Whip says it really hit home during a heatwave in 2014 when the temperature recorded on his property was between 46–50 degrees for 12 days straight.

"I think we lost probably two or three in that time, which were, you know, unexplainable.

"They weren't poor, they just sort of stopped. I think they stopped eating and just gave up the ghost a bit."

It is something Mr Whip is trying to get to the bottom of and he is working with researchers from the University of Southern Queensland to find ways to keep cattle going through extreme heat.

He has destocked his farm, changed breeding and put other measures in place. For example, he is ready with high-energy supplements to feed his animals.

"It's now ready to go, if we get back into those extreme conditions again, we'd look at trying to feed [cattle] that, just as a … bit of an energy boost, a bit of a kickalong just for that period."

Adapting to a changing climate

Farmers are intimately connected to the land and dependent on the climate to produce food, but the unpredictable nature of the climate is changing things.

Professor Richard Eckard from the University of Melbourne says agriculture relies on a predictable local climate.

"Every crop exists where it does because we know the distribution of rainfall and we know the distribution of temperature," he says.

"Climate change threatens those, it threatens the rainfall and it threatens the temperature regimes that a crop or a system is adapted to."

Generally there is a southward movement in weather systems, with both temperatures and rainfall zones on the move.

"And so, it affects almost everything we can grow in the future," Professor Eckard says.

But from cattle to wheat and fruit, he says farmers across the country are adapting.

"We think a lot of adaptation taking place amongst farmers even if they're not overtly acknowledging that it is climate change, we're just seeing them responding to the environment.

"I guess that's what farming is, it is adaptive management to your environment and if those changes are taking place, they adapt."

When grain farmer Mark Adams first started out 30 years ago, his biggest challenge to growing crops was waterlogging.

But on his property at Mt Barker in the Great Southern region of WA, rainfall patterns have changed drastically.

"Our annual rainfall has declined about 15 per cent, but probably the biggest change has been the distribution of rainfall, so our rainfall now occurs outside of our traditional winter months," Mr Adams says.

The declining rainfall is challenging many farmers but for others their once too-wet land is now perfect for growing crops, and cropping regions across the country are moving south.

The combination of lower rainfall and better farming techniques has helped Mr Adams increase his productivity by 25 per cent.

"We've been adapting for the last 30 years and I don't think we're going to stop adapting to what the climate throws at us," he says.

"I don't have a fear in regards to climate change. We've managed with the changes to date and we've increased our production."

Farming scallops in warming seas

In Port Phillip bay overlooking Melbourne, Andrew Zapantis is preparing his boat for the opening of the scallop season.

On the back of his boat is a harvester that goes down 50 metres to retrieve the scallops.

"It's a fishery that goes from one extreme to the other. So you could be riding a really high wave and then not, that's just the way the scallop industry is," Mr Zapantis says.

Right now, he says, the industry is riding a high, with all signs pointing to a good season, which runs from July to December every year.

But that won't last forever. Seas off south-east Australia are some of the fastest warming waters in the world.

A report from the University of Melbourne warns together with changes in oxygen and food, this could mean Southern scallops could disappear entirely.

On top of that, increasing acidity in the water thins their shells, reduces their growth, survival and reproductive success.

"That is a concern. I'm not sure where it's all going to head but obviously you won't have much of an industry left. It's not a good feeling that's for sure," Mr Zapantis says.

Extreme heat takes toll on fruit, nuts

On the edge of the Gawler River in South Australia, farmer Annmarie Brookman has been ripping up pistachio, walnut and apple trees.

She planted the pistachios 30 years ago because they grow with relatively little water and tolerate high temperatures, but they rely on winter chill to regenerate.

"So warmer night temperatures in winter have affected us in terms of pollination. And the way that happens is that if you do not reach enough winter chill, then the synchronisation of bud burst in spring doesn't happen," Mrs Brookman says.

Apples also rely on winter chill and on top of that Mrs Brookman's apples weren't coping with extreme heatwaves.

Despite not being in a traditional apple-growing region, she said the first 15 years went well, but that all changed with record-breaking heatwaves that saw multiple days over 42 degrees and overnight temperatures in the high 20s.

"Nothing had a chance to recover overnight and start the next day off fresh, we just found that it completely cooked the apples and the nashis on the sides that were exposed," Mrs Brookman says.

Harder than pulling out the apples, she says, was the decision to pull out the walnut trees.

"The sad thing is pulling them out but the good thing is seeing how other things cope and you know, we've already had good crops of pomegranates and we've had good crops of jujubes so I guess all is not lost."

The right time and place for carrots

Angelo Lamattina's family has been growing carrots in the north-west corner of Victoria since 1991.

"The reason why we chose the area we're in is because it had plenty of water and the soil was perfect for growing carrots and the climate conditions were also perfect."

But in recent years it's been getting too hot.

After hard times during drought in the early 2000s they decided to buy another property in Kaniva, 300 kilometres south of the family farm. And a few years ago, they bought a third property at St George in southern Queensland.

They grow carrots in Queensland for 10 weeks of the year, at Kaniva for six months, and four months at Wemen.

"That gives us the opportunity to grow the carrots at the exact right time of the year with no risks, having the best soil at the time and economically using the water," Mr Lamattina says.

"If you're growing your product at the right time of the year, it's not too hot, not too cold. The amount of water you need to grow [carrots] is a lot less."

Mr Lamattina says climate change is a big issue for a lot of farmers.

"The point is actually the climate is changing and so we need to adapt, we have done that.

"We sort of feel that we're nearly, not say droughtproof, but droughts then can come and go and not affect the business as much as it would have 20 years ago."

But Professor Eckard warns that as climate change accelerates, it's getting harder for food producers, and there needs to be more investment from both state and federal governments.

"A lot of research is still needed to understand what are the adaptation options and to progress some of the adaptation options," he says.

"Because if they are about breeding shorter-season varieties, well we actually need quite a long lead time to get there. It doesn't happen tomorrow."

Grazier Peter Whip says the political discussion about climate change is hampering that progress.

"Generally, most farmers are good at adapting. They have to be to survive, to manage drought," he says.

"I guess my hope for the future would be that rather than government using agriculture as a bit of a political football, that we would all get on the same page — environmentalists, farmers, government."

Data sources

Cattle, apples and carrots: Bureau of Meteorology's closest available station with sufficient historical record

Wheat: Bureau of Meteorology Climate Change — trends and extremes

Scallops: Supplied by Andrew Lenton, CSIRO

Topics: climate-change, rural, horticulture, grain, fruit, fishing-aquaculture, vegetables, weather, beef-cattle, longreach-4730, kaniva-3419, gawler-5118, melbourne-3000, st-george-4487, mount-barker-6324

First posted