How Climate Change Is Shifting the Equation for Viticulture

Let’s face it: farming has always been difficult.

Since humans evolved from hunter/gatherers to agronomists, toiling in the soil has never been easy, given the reliance on favorable soil and weather conditions to ensure viable crop yields, year in and year out.

Viticulture, of course, is no exception. That perfect terroir we seek, encompasses, as the New Oxford American Dictionary says, “the complete natural environment in which a particular wine is produced, including factors such as the soil, topography, and climate.”

Ah, climate. Therein lies the rub.

While farmers and viticulturists have always been subject to the vagaries of nature, the undeniable warming of the planet is having sobering effects on vineyards around the globe, giving grape growers pause in a way that is unprecedented.

Consider this: climate science indicates that greenhouse gas emissions have warmed the earth by 1.1 degree Celsius, the equivalent of nearly 2 degrees Fahrenheit since the 1880’s, with warming happening twice as fast in this century as the last (climate.gov, 2023).

The effect of that warming, according to a recent study from Stanford University, means that global farming productivity has dropped 21 percent, since the 1960’s, the equivalent of losing about seven years of agricultural advances. (Stanford Woods Institute for the Environment, April, 2021).

Wil Franklin is the owner, vineyard manager and winemaker of Trinity River Vineyards (TRV), a boutique winery based out of Humboldt County, CA in Willow Creek, one of the smallest AVA’s in the state: https://www.trinityrivervineyards.com.

Franklin sources grapes from northern California’s coastal counties of Humboldt, Lake and Mendocino. Although TRV’s case production is relatively modest, Franklin cut his teeth on the wine industry in California’s Central Valley, so knows his way around the state’s viticulture issues, large and small.

While Franklin concedes that farming has always involved degrees of uncertainty in terms of what Mother Nature delivers, he believes the extremes of climate change are different, causing growers everywhere to scramble to meet its challenges.

“The variability (of climate conditions) is hard on farmers and hard on vineyard quality,” Franklin opines. “Water is a huge issue for most of California. The best vineyards have traditionally been in shallower soils using dry farming … but most high-end wines grown there aren’t sustainable in today’s world. 

“Viticulturists (now) need to make money and save water at the same time. That creates tension between those two very real forces.”

Franklin’s concerns about vineyard quality is shared by a host of other scientific experts. 

According to a recent article in Knowable Magazine, “warming, wildfires and unpredictable weather” are altering the chemistry and sensory profiles of grapes and wine around the world.

The authors, who researched the issue in two of the world’s most renowned wine regions, Bordeaux, France and Napa, CA, maintain that wine quality depends on three primary aspects of grape berries; sugar, acids, and secondary compounds. 

“When a region’s climate changes, that can disrupt the balance of sugar, acid and secondary compounds by changing the rate at which they develop over the growing season,“ explains Megan Bartlett, a plant biologist studying viticulture at UC Davis, who is quoted in the Knowable Magazine article. 

Bartlett points out that, “grapes, like most fruit, break down acids and accumulate sugar as they ripen. At warmer temperatures, ripening is supercharged, leading to sweet, raisin-like flavor ...” , which in turn, leads to higher alcohol wines, with lower amounts of acidity, resulting in “flabbier” wine texture. (Knowable Magazine, June 2022)

In short, climate change implications for the vineyards and for the bottle are profound in ways they have not been before.

And yet, if there’s anything farmers are known for, it’s resilience.

As the New York Times reports, “the accelerating effects of climate change are forcing the wine industry, especially those who see wine as an agricultural product rather than an industrial beverage, to take decisive steps to counter or adapt to the shifts.” (The NYT, 6/2023).

According to the Times, those steps are happening in five crucial ways:

1. Expanding the wine map to cooler climates. In the Northern Hemisphere, it means looking for sites further north and in the Southern Hemisphere, it’s the opposite. Places never before considered hospitable for grapes are now growing them, like England along its southern coast, Belgium, Denmark, Norway, Sweden and in the Canadian provinces of Ontario and British Columbia.
2. Producers are planting at higher altitudes. In Catalonia, Spain, vineyards are sprouting up at altitudes of 3,000 to 4,000 feet in the Pyrenees, which, according to the article “would have been impossible 25 years ago.” The increased diurnal shift – temperature changes over the course of 24 hours – stabilizes temperature swings and helps grapes ripen at a more even pace.
3. Curtailing sunlight and moving vineyards from south facing to north facing slopes, depending on which hemisphere in which the vineyards are located. For instance, in Australia, south facing slopes now benefit from a relatively cool climate and growers are orienting accordingly. The opposite is true in the U.S.
4. Different grape varieties. In Bordeaux and Napa where Cab is King, growers are beginning to experiment with different varieties less susceptible to climate change. In France, seven additional grapes have been selected, experimentally, for inclusion in Bordeaux blends; four reds (touriga nacional, marselan, castets and arinarnoa) and three whites (albarino, petit manseng, and liliorila).
5. Forest fire, floods and droughts are the result of weather that is no longer predictable. Therefore, growers know it’s imperative to find technological solutions to the irrigation shortages, smoke taint and storm damage that negatively impact their crops.

In California and Australia, growers are responding by grafting vines onto drought resistant rootstock, as well as selecting different grape varieties. And oversees, vintners are experimenting with a variety of methods to protect their vines from unseasonable hailstorms, ranging from cloud lacing to vine netting.

As Franklin points out, new technologies are supplying viticulture with irrigation tools for drought stricken areas, “just in time.”

“Water can be delivered straight down through tubes to the root stems, with sensors that measure saturation levels and give growers all kinds of critical information,” Franklin observes. “For small organic growers though, affordability might be an issue. “

However big or small the vineyards, and wherever they are located, it’s clear that contemporary viticulture will require all the grit and determination that growers have exhibited over the ages, along with all the cutting-edge technology possible.

With Canada experiencing its worst fire season in recorded history – to date, 17.5 million acres have burned, with no end in sight – it appears that our industry, and our environment depend on it.