Climate change puts heat on ag

In 70 years, if humanity continues to pollute the atmosphere at the same rate, current climate zones may have shifted 900 kilometres south.

Even more difficult for agriculture, the new Feeding a Hungry Nation report observes, will be the rising number of very hot days as the climate changes.

“Dubbo, for example, which in today’s climate experiences 22 days per year above 35°C, could see a trebling of hot days to 65 per year by 2090 under a high emissions scenario,” the report’s Climate Council authors observe.

The Climate Council, initially appointed to provide independent advice to government and publicly funded to do so, had its funding withdrawn by the Abbott government but has continued to operate on private donations.

The Feeding the Hungry Nation report looks at the intersection of climate change and agriculture. Shifting climatic patterns are highly likely to affect Australian households “as food prices and food availability become more volatile”, and on the economies and social fabric of rural communities that depend on agricultural prosperity.

Climate has always been a natural constraint on farm productivity growth in Australia.

The 2015 wheat crop is now forecast to be about 24 million tonnes, well shy of the 27.4 mt record crop of 2010-11, after yield losses because of a dry spring and a record-breaking early October heatwave.

The Australian cattle herd is at a 20-year low after two years of high turnoff because of drought.

These knockbacks have occurred within the envelope of Australia’s natural climate variability. Climate change is introducing greater variability to a country where rainfall is already three times more variable than in the United States, and double the variability of New Zealand.

These changes will occur as global population soars, potentially inhibiting Australia’s ability to contribute to heightened demand for food, and to profit from it. Some analyses suggest that Australia’s ability to contribute to global food production will be even reduced.

For instance, the report observed, a projected doubling in the frequency of the “spring drought” that has plagued south-eastern Australia in the 21st Century could reduce national income $7.4 billion annually, equivalent to lowering GDP by one per cent per annum.

Small rises in average temperature can have subtle but costly effects - on yield of grain crops, sugar content of horticultural crops, the performance of dairy and beef cattle. The natural ranges of pests and diseases are changing, and will continue to change.

The report digs into some detail on all of these issues.

Australian agriculture can continue to adapt incrementally to these changes, as it has been doing. Over the past 15 years, in response to reduced rainfall and waterlogging, Victorian farmers have greatly expanded their cropping operations.

But incremental adaptation won’t be enough, the report’s author argue. “The present day match between suitable climate, and the requirements of some agricultural enterprises, will become progressively decoupled.”

Instead, “transformational adaptation” might be necessary - like the wine industry’s progressive migration to Tasmania as warming reduces grape quality in traditional wine-growing regions like South Australia.

But those changes are expensive and risky, and the financial hardship being experienced by many farmers limits their capacity to invest in adaptation.

And, the report’s authors wrote, “if the present rate of climate change is maintained, there will be many challenges to which adaptation is simply not possible”.

The only assuredly safe option, in the view of the Climate Council, is for a global switch to a “low carbon” world economy within the next decade, thus curtailing the emissions that are driving climate change.

“Achieving carbon neutrality in the land-based sector, including agriculture, will play a vital role in the transition we must embrace.”