Huge tracts of potential wine-producing country are expected to vanish from Australia over the next few decades as climate change bites, and winemakers may need to head for higher, cooler ground.
A new international study, published in the journal Proceedings of the National Academy of Science, estimates that up 74 per cent of the nation's potential vineyard country will become unsuitable for growing the right grapes.
But that figure comes with caveats, because most existing wine districts, such as the Hunter Valley in NSW and Western Australia's Margaret River, should be able to adapt their farming practices to cope with the change.
Vast areas of France, Italy, and other long-established wine-growing districts would also be affected.
''Global changes in suitability for wine production caused by climate change may result in substantial economic and conservation consequences,'' said the study, Climate change, wine, and conservation.
''Redistribution in wine production may occur within continents, moving from declining traditional wine-growing regions to areas of novel suitability, as well as from the Southern Hemisphere to large newly suitable areas in the Northern Hemisphere.''
The study used 17 global climate models to estimate temperature and moisture changes around the globe over the next four decades. Grapes are sensitive to minute changes in air temperature, water level and soil composition, so many growers might have to change the type of wine they produce, the study said.
International demand for wine is expected to increase along with temperatures, so vineyards may be forced to relocate or expand into areas not currently suited to grape growing, disturbing existing ecosystems.
In general, wine production would gradually be relocated to higher, cooler areas, the study said. While Australia should be able to adapt and experience little or no net loss of current wine production, New Zealand would benefit as more high-altitude, cooler areas opened up to viticulture.
Researchers at the CSIRO have also explored the question.
An earlier study, led by CSIRO researcher Leanne Webb, found that just under half of Australia's potential wine country could become unsuitable for future production by 2050 - though with the same caveat that winemakers could probably adapt with new management techniques and more dense vineyard development in the remaining suitable areas.
In one study, Dr Webb examined grape ripening times in 44 separate vineyards across the country. She found that all the areas, bar one, grapes were ripening earlier, and at a faster rate.
Long-established vineyards had seen grapes ripening 0.8 days earlier each year for many decades, but in the last 20 years that rate had increased to 1.7 days earlier each year.
''If you take it forward, by 2050, we found that grapes would be ripening a month earlier,'' Dr Webb said, though she added that this was probably an underestimate and that change would take place before 2050.
A five-year CSIRO study, involving anonymous interviews with dozens of winemakers, found that many were adapting fast to the changes.
Two of the participating wineries have already purchased properties in Tasmania, and others had begun sourcing grapes from there.
"I think that we're going to be able to cope with climate change because we've got a broad range of opportunity to go south," one winemaker told CSIRO researchers.