Swapping grape varieties can significantly offset damage that would be inflicted on some wine regions by higher temperatures linked to climate change, says a study published in the Proceedings of the National Academy of Sciences (PNAS) this month.
Up to 56% of current wine growing land may no longer be suitable for vineyards if the planet warms by two degrees Celsius – the upper limit set by the Paris Climate Agreement – says the study.
That figure rises to 85% if warming hits four degrees, says the study, which used historical growing season data for 11 grape varieties, including Cabernet Sauvignon, Pinot Noir and Chardonnay, to create its model.
It is one of the starkest warnings so far about the size of the climate challenge facing vineyards.
But, it says there’s still time to adapt and that switching grape varieties could reduce losses by more than half in some cases.
However, the research acknowledges the financial, cultural and legal hurdles to, say, replacing Pinot Noir with Grenache in Burgundy or uprooting Cabernet Sauvignon for Mourvèdre in Bordeaux – even if expanding the number of varieties allowed in certain Bordeaux appellation wines was approved by winemakers last year.
The PNAS study authors said they had taken previous studies further by using more comprehensive data and looking at several grape varieties simultaneously.
Dr Elizabeth Wolkovich, one of the lead authors and from the University of British Columbia in Vancouver, told Decanter.com that extensive adaptation of vineyards might prevent the worst scenario in some cases, perhaps with fewer good vintages.
But she added, ‘We’ve only seen to date roughly a quarter of the warming we expect by the end of the century given the current emissions, so growers need strategies that will work for much greater warming; or an aggressive global strategy to limit further warming.’
Paris Agreement targets
The Paris Climate Agreement set a goal of limiting warming to, at most, two degrees above pre-industrial levels this century.
Cooler wine regions, such as New Zealand, the Pacific Northwest and Germany, would be relatively unaffected in this scenario, says the PNAS study.
However, the world was on-course to overshoot the Paris target last year, according to the United Nations Intergovernmental Panel on Climate Change.
More about the study
The PNAS study, led by Dr Ignacio Morales-Castilla at the University of Alcalá in Spain alongside Dr Wolkovich, looked at 11 varieties: Cabernet Sauvignon, Chasselas, Chardonnay, Grenache, Merlot, Monastrell/Mourvèdre, Pinot noir, Riesling, Sauvignon Blanc, Syrah/Shiraz, and Ugni Blanc.
They mainly drew on French records for bud break, veraison and harvest dates going back to 1956.
They used existing data on warming scenarios to help build models for how the 11 different wine grapes would perform in future and produce forecasts for wine growing regions.
Researchers said they hoped the study would also be of use to other agricultural sectors.
‘In some ways, wine is like the canary in the coal mine for climate change impacts on agriculture, because these grapes are so climate-sensitive,’ said study co-author Benjamin Cook, from Columbia University’s Lamont-Doherty Earth Observatory and the NASA Goddard Institute for Space Studies.
‘The key is that there are still opportunities to adapt viticulture to a warmer world,’ said Cook. ‘It just requires taking the problem of climate change seriously.’
Look out for Tim Atkin MW’s feature on climate change in Burgundy in the March issue of Decanter – on sale 5th February 2020.
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