Wine lovers take note: the celebrated diversity of your favorite tipple could also be the key to its survival under climate change.
A new study, published in PNAS, finds that under future temperature increases of 2 °C, up to 56% of wine-producing land across the planet will no longer be suitable for that purpose. And if global temperatures increase by 4 °C, the loss rises to 85%. Yet, if wine farmers embrace grape diversity and reshuffle their crops accordingly to suit climate stresses in decades to come, it could save more than half those lands from loss, under a 2 °C increase, and one-third of winelands under 4 °C.
The study, which was produced by an international team of researchers, including scientists from NASA, emphasizes that a degree of wineland loss under climate change will be unavoidable, especially under the higher temperature scenario. But substituting in more resilient grapes in years to come—a process called ‘turnover’—offers a unique, oven-ready solution to this threat, thanks to the long history of grape-breeding that has resulted in over 1100 varieties for farmers to fall back on.
The researchers revealed the richness and potential of this genetic resource when they traced back through extensive historical records and more recent academic research on 11 grape varieties, including Cabernet Sauvignon, Chardonnay, and Pinot noir. From this body of data they extracted information on when each variety would bud and ripen, and under which optimal weather conditions. (It’s thought that shifts in temperature play a larger role than rainfall in altering the level of acids and sugars in grapes—thus influencing the quality of wine and viability of production.)
When they plugged this growth data into a climate model, it revealed which grape varieties would fare better in different parts of the world, under the two different projected climate scenarios. That showed how effectively switching grape types could change the fate of wine-growing regions: for instance, heat-sensitive Pinot noir in parts of France could be replaced with more heat-tolerant varieties like Grenache, a type of grape that ripens late, and so requires hot, dry conditions.
Losses and gains won’t unfold uniformly around the world, however. Warmer regions will go on to suffer the most in the future; in some countries like Spain, greater crop diversity won’t be enough to stave off losses of almost 70%, the researchers found. On the other hand, currently cooler parts of the world—like the Pacific Northwest of America and parts of New Zealand—will experience an expansion in suitable wine-growing habitat as temperatures warm.
Intriguingly, the 11 grape varieties the researchers included in their analysis only covered about 1% of wine grape diversity—highlighting how much more potential there could be for different grape types to shore up vulnerable wine-growing regions against climate change. Having this huge repository of information could cue farmers on which types will fare best on their land in coming years.
Wine producers are lucky to have a plethora of crops to draw on in the future. And this underscores why diversity is so crucial in adapting to climate change: it’s a lesson that could be applied to many other types of agriculture, such as rice farming, wheat, or banana production, where an eager hunt for new crop varieties is now on.
But at the same time, the researchers on the new study are at pains to stress that diversity isn’t a cure-all: even with more varieties to rely on, some wine-growing regions of the world will unquestionably fade away if we have unchecked climate change. That’s why capping global temperature increases at 2 °C or below is still the most powerful solution, they say.
On both these fronts—changing farming methods and capping emissions—the researchers emphasize “the critical role that human decisions play in building agricultural systems resilient to climate change.”
Source: Morales-Castilla, et. al. “Diversity buffers winegrowing regions from climate change losses.” Proceedings of the National Academy of Sciences
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