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In 2090, will northern Australia be the best place to grow mangoes? - ABC

Northern Australia is synonymous with mangoes and for decades the Kensington Pride variety has dominated orchards and supermarket shelves.

But with a changing climate, does the industry's future lie further to the south and with different varieties?

At the National Mango Conference in Darwin this week, growers have been shown long-range climate projections, which suggest the north's mango growing regions will get a lot warmer in the coming decades.

Mangoes are quite sensitive to temperature, requiring a certain minimum temperature for a number of nights to trigger flowering and then avoiding extreme heats which can affect production.

David Karoly, who heads up the Government's Earth Systems and Climate Change Hub within the CSIRO, said over the last 10 years the mango industry "had already seen temperature changes that were impacting mangoes".

"When we look into the future we seen even bigger [temperature] changes for the next 20 to 30 years," Dr Karoly said.

"What happens beyond that depends on what Australia and the rest of the world does to limit climate change, but in a worst-case scenario what we see is that in 30 to 50 years from now, we would see temperature changes of two to three degrees warming and that would put at risk much of the mango industry in the Northern Territory [and other parts of northern Australia].

"Mangoes may not be viable in 30 to 40 years time [in these regions] unless the world acts on climate change".

The Kununurra example

Kununurra in Western Australia's far north has the highest average temperature of any mango-growing region in Australia, and over the last 10 years Kensington Pride (KP) yields have been on the decline.

A report by Earth Systems and Climate Change Hub concluded the region's mango industry "will need to change varieties in order to remain viable".

"Kensington Pride is struggling physiologically under Kununurra conditions to accumulate enough carbohydrates to support a crop," it said.

"The variety is under high stress for most of the growing season.

"Any increases in average temperature will only exacerbate the problem, and more irregular wet season patterns will severely limit the variety's ability to accumulate carbohydrates".

Kununurra grower Quentin Parker has seen the demise of KP yields first-hand and has decided to rip some trees out and replace them with a new variety, currently named NMBP 4069.

"It was bred in Kununurra and I feel this is where we need to be looking, something that's bred locally and might be more assimilated with our climate and our changing climate," he said.

"I had some 30 year old [KP mango trees] on a property I recently purchased and got 150 boxes of mangoes, off 200 trees, two years in a row and thought 'this is not good, this has to stop'.

"So these new ones are in the ground and they're looking very promising."

Should the mango industry abandon the north?

Growing mangoes in Victoria might sound crazy, but it is already happening.

There is also a growing list of farmers who are making investments based largely on climate change concerns — the Brown Brothers wine company perhaps the most famous case.

NT Department of Primary Industry mango researcher, Cameron McConchie, said looking at the climate data, it would seem areas further south such as Carnarvon, WA, could be a great place to invest in future plantations.

Mr McConchie said he was confident though, that the industry could find other solutions to cope with a changing climate, other than just moving production down south.

Options include:

  • Select existing adapted cultivars (such as the NMBP 4069)
  • Develop new cultivars
  • New chemicals that disconnect flowering from climate
  • Develop cost effective structures that modify weather extremes to improve cropping
  • "In my opinion [the mango industry] has to be worried about climate change," he said.

    "I mean the number of cold nights will decrease and the number of hot days will go up, both of which will limit production.

    "There's a really nice tool that CSIRO has developed [to look at climate projections] for mango regions, and you can see that by 2040, the Darwin region will become like Kununurra is now, and if they're struggling, then we will struggle.

    "But I do believe that if the industry has a long term interest in growing mangoes then there are solutions to these problems."

    ABC