Sour grapes: ‘Warmer days could threaten your wine'
Don’t take that chilled glass of wine on a warm day for granted, hotter temperatures could be threatening the grape.
Multiple studies suggest many of the world’s regions that are suitable for planting wine grapes could be lost to climate change.
However, new research indicates that swapping out the pound-sized fruit for more drought and heat tolerant varieties can offer a way forward for winemakers.
Senior author Elizabeth Wolkovich, a professor of forest and conservation sciences at the University of British Columbia, said: “Substituting Grenache or Cabernet Sauvignon for Pinot Noir, planting Trebbiano where Riesling is grown – these aren’t painless shifts to make, but they can ease winegrowers’ transition to a new and warmer world.”
Combining long-term records with global data, researchers suggest that if temperatures rise by 2C, the regions of the world that are suitable for growing wine grapes could shrink by as much as 56%, according to a new study.
And with 4C of warming, 85% of those lands would no longer be able to produce good wines, researchers say.
Prof Wolkovic added: “These estimates, however, ignore important changes that growers can make.
“We found that by switching to different varieties, vintners can lessen the damage, to just 24% of areas lost.”
The researchers focused on 11 varieties of wine grape, based on their diversity in development timing, a key trait for climate adaptation.
They selected cabernet sauvignon, chasselas, chardonnay, grenache, merlot, monastrell (also known as mourvedre), pinot noir, riesling, sauvignon blanc, syrah and ugni blanc.
Using vinter and archives they built a model for when each would bud, flower, and ripen in winegrowing regions around the world under three different warming scenarios: 0, 2, and 4 degrees of warming.
Then they used climate change projections to see where those varieties would be viable in the future.
Losses were unavoidable in both warming scenarios, due to shifting temperatures and seasonal changes that would affect conditions while the varieties were ripening.
However, the scientists discovered that by switching the varieties around “you can reduce losses by a significant amount”.
They suggest, that for example in France’s Burgundy region, heat-loving mourvedre and grenache could replace current varieties such as pinot noir.
In Bordeaux, cabernet sauvignon and merlot could be replaced with mourvedre.
According to the study, cooler winegrowing regions such as Germany, New Zealand and the US Pacific Northwest would be relatively unscathed in the 2C scenario.
Published in the Proceedings of the National Academy of Sciences, it sets out these areas could become suitable for warmer varieties like merlot and grenache.
While varieties that prefer cooler temperatures, such as pinot noir, could expand northward.
However, the researchers acknowledge there are legal and cultural hurdles in shuffling grape varieties around.
Prof Wolkovich said: “The effectiveness of any strategy depends on both the grape growers and people in general.
“Consumers who are willing to try new varieties can play a big part in helping save the regions people love.
“Legislation can encourage growers to test out new varieties. And ultimately, people can make the largest impact through work to reduce emissions globally.”
Researchers say that regions which are already limited to planting the warmest varieties – such as Italy, Spain, and Australia – face the largest losses.
They also found that variety-swapping was less effective at higher amounts of global warming.
With 4C of warming planting climate-specific varieties reduced losses from 85% to 58%.
The researchers note that management practices like increased irrigation and using shade cloths can also help to protect grapevines, but only at lower levels of warming.