Warning to winemakers: grow new grapes or perish

Climate change is creating myriad challenges for the world’s farmers, including wine-grape growers. Vignerons may be able to overcome some obstacles by planting grape varieties that are better suited to altered vineyard conditions but, before this can happen, according to a new study published in Nature Climate Change, scientists and winemakers alike need to better understand the wide diversity of grapes and their suitability to different climates.

A significant stumbling block in convincing wine producers to try different grape varieties is the cherished concept of terroir, says the report’s author, climate-change biologist Elizabeth Wolkovich from Harvard University in the United States.

Terroir is the belief that a wine’s character is a reflection of where and how the specific varieties of grapes were grown. Thus, only certain traditional or existing varieties are part of each terroir, leaving little room for change.

“There’s a real issue in the premier wine-growing regions, that historical terroir is what makes great wine, and if you acknowledge in any way that you have climate change, you acknowledge that your terroir is changing,” Wolkovich says. “So in many of those regions there is not much of an appetite to talk about changing varieties.”

She believes wine producers now face a choice: proactively experiment with new varieties, or risk suffering the negative consequences of climate change: “With continued climate change, certain varieties in certain regions will start to fail – that’s my expectation.” 

In February 2017 Wolkovich told a Harvard-organised conference called Global Food + that research from 2014 indicates global warming would see wine-grape production move into northern Europe and locations along the Canadian-US border, but that “we don’t expect to be able to grow wine grapes by the end of the century in large parts of Italy, much of Spain, and some of our favourite regions of France, including Bordeaux, Cotes du Rhone and Burgundy.”

In this latest report, she challenges wine producers to start thinking of varietal diversity. “Maybe the grapes grown widely today were the ones that are easiest to grow and tasted the best in historical climates, but I think we’re missing a lot of great grapes better suited for the future,” she says

However, even if an appetite for change existed, she adds, researchers don’t yet have enough data to say whether other varieties would be able to adapt to climate change.

“Part of what this paper sets up is the question of how much more do we need to know if we want to understand whether there is enough diversity in this crop to adapt wine regions to climate change in place,” says study co-author Ignacio Morales-Castilla, a Fellow at Harvard’s Arnold Arboretum, who investigates wine-grape varieties and their adaptability under climate change. 

“Right now we know we have this diversity, but we have little information on how to use it,” he says. “One of our other suggestions is for growers to start setting aside parts of vineyards to grow some other varieties to see which ones are working.”

In Europe, Wolkovich says, growers have the advantage of tremendous diversity. They have more than 1000 grape varieties to choose from, research repositories such as the French National Institute for Agricultural Research, and expertise in how to grow different varieties. Yet strict labelling laws have created restrictions on their ability to take advantage of this diversity.

For example, just three varieties of grapes can be labelled as wine from Champagne and four for Burgundy. Similar restrictions have been enacted in many European regions – all of which force growers to focus on a small handful of grape varieties.

“The more you are locked into what you have to grow, the less room you have to adapt to climate change,” Wolkovich says. “So there’s this big pool of knowledge, and massive diversity, growers have maintained an amazing amount of genetic and climatic response diversity … but if they changed those laws in any way in relation to climate change, that’s acknowledging that the terroir of the region is changing, and many growers don’t want to do that.”

Winegrowers in other parts of the world, meanwhile, must grapple with the opposite problem: there are few, if any, restrictions on which grape varieties may be grown in a given region, but growers have little experience with the diverse – and potentially more adaptable – varieties of grapes available.

Just 12 varieties account for more than 80% of the grapes grown in Australian vineyards, Wolkovich says, and  cabernet sauvignon comprises more than 75% of all the wine grapes grown in China, chiefly because these are the wines consumers want to buy. {%recommended 847%}

Cameron Leith, a second-generation Australian winemaker from the Passing Clouds winery, near Daylesford in western Victoria, helped his father move their original operation almost 120 kilometres south, from north-west Victoria to its present location, about seven years ago.

Drought and climate change were major factors, he says, leading to commercially unsustainable crop yields.

Leith believes Australia is well placed to experiment with new or different grape varietals. “We have the freedom here to plant whatever varieties we think will work best for our sites, both now and in the future,” he says. 

“I believe there are many Australian grape growers already doing this, and we have plenty more that are well placed to do so. Perhaps all it would take is an extra push, such as further research – particularly into the costs to growers of the wrong varieties in the wrong place – as well as education by our grape and wine organisations.”

Wolkovich adds: “They have all the freedom in the world to import new varieties and think about how to make great wines from a grape variety you’ve never heard of, but they’re not doing it because the consumer hasn’t heard of it. We’ve been taught to recognise the varieties we think we like.”