Viticulture and water woes

Wednesday, 13. December 2017 - 16:00

Nevil Dilmen/Wikicommons

In late October, the Tasting Climate Change conference  - Canada’s first wine conference on the impact of climate change - took place in Montreal. Organised and moderated by myself, it brought five experts from five different fields together to share their insights on the state of the health of the planet. The challenges specific to the wine industry were discussed, with water management high on the priority list. Should vines be planted if they need to be irrigated was a key question. 

No irrigation?
Climatologist Dr Gregory Jones, a specialist on the impact of climate on viticulture and the director of wine education at Linfield College in McMinnville, Ore. started the debate. If there was no more irrigation of vines, most New World wine regions would simply not exist.  “They correspond to 40% of the world acreage right now,” he says. “In Europe the climate is different. The Atlantic and Mediterranean oceans bring moisture in the atmosphere and more water during summer.” Dr Jones says that Bordeaux gets 45% to 55% of rain during the growing season where Napa gets 5% to 10%. “If we stopped irrigating we would remove most of the New World viticulture,” he says.   

Dr Pedro Parra, world-renowned terroir expert and consultant who holds a PhD from the Institut National Agronomique de Paris Grignon and a Master degree on Precision Agriculture from the same Institut, didn’t completely agree. He thinks that the need for irrigation would be much less and in many cases not necessary if quantity and money were not driving decisions. 

“In many places, I think you can plant without irrigation,” he says. “The problem is that you might not have grapes in the first six years. Is the producer prepared to wait for that amount of time?” He went on to say that, “with irrigation you can get 2.5 kg of grapes per vine. If you don’t irrigate you produce four hundred grams. I am convinced that in Chile we can do dry farming all around – we just need proper rootstocks, good viticulturists and another economical model.”

Dr Parra asked rhetorically if the market would be prepared to pay more for Chilean wine. “It looks like the answer is ‘no’. So people produce 10,000 kg per ha to 20,0000 kg per ha, then we hire a winemaker and we make a $5.00 bottle of wine. The real problem is money.” Dr Parra added that some of his Sonoma clients do not irrigate, proving the point that it is possible and viable.  “Personally, I believe that when money drive decisions, it rarely finishes in a happy ending,” he says.

Renowned oenologist and consultant Alberto Antonini, who also collaborates with Dr Parra, shares the same philosophy. He says that the conventional viticulture developed over the past 40 years “does not help to reduce the water needed in a vineyard”. Indeed, soils damaged by “no soil cultivation” and the use of herbicides need more water, because they do not “allow the rain to penetrate and to be available to vines. The roots cannot penetrate deep down and most of them are developed in the topsoil where there isn’t much water available, as it evaporates quickly.”  

Antonini says other  viticulture practices also pose problems. He says that, in many cases, the rootstock selected is not the most appropriate for a dry environment, making the vines more water stressed. Vine density is another issue. “Vine density and trellising systems are often not appropriate for dry environment,” he says. “Traditionally, growers were planting at low density and developing small vines (bush vines or guyot) as opposed to many ‘modern vineyards’ today which are planted with high density and therefore are more water demanding.”  To Antonini, good soil management will save water. Such measures include creating a soft soil with good porosity and drainage for air and water; a deep root system and the use of appropriate rootstock; as well as low density planting and small vines. “People don’t take advantage of all of the little rain they can get in some areas because they know they can irrigate” he says. “Let’s think of irrigation last. First, think of what you can do to optimise water availability.”

But even if dry farming becomes more widespread, the use of irrigation is growing – even in European regions where irrigation was once prohibited. Appellations like Châteauneuf-du-Pape are increasingly able to use irrigation during heat spikes. “I am very traditionalist,” says Thomas Perrin of Château Beaucastel. “The only reason I would irrigate is if there would be a danger for the vine’s life.  But it would be a very difficult decision. If less water means that we would reduce the crop by 40% or 50% I would not irrigate.” But even if winemakers are reluctant to use irrigation, they may have to, as heat events become more extreme.

Water as luxury good
This raises a crucial question: Is wine, a luxury product, worth all the water that goes into it? In a 2011 document published by the Food and Agriculture Organization of the United Nations called “The State of the World’s Land and Water Resources for Food and Agriculture,” research shows that the world’s cultivated area has grown by 12% over the last 50 years. The net increase in cultivated land is the result of irrigation. Agriculture uses 11% of the world’s land surface for crop production and makes use of 70% of all water used from aquifers, streams and lakes. As 2050 approaches and the global population increases by 2bn people, global food production is predicted to rise by 70%, relative to 2009. With such a rapidly growing demand for food, water access will become an even bigger problem. So which crop will be left behind? Should the wine industry stop irrigating its vines altogether?

Steven Guilbeault, the co-founder and CEO of Montreal-based Équiterre, took the stage to discuss this issue. Previously, Guilbeault worked for Greenpeace Canada and Greenpeace International for 10 years and has co-chaired Climate Action Network International and attended many UN climate meetings. “In a world where access to water will become more difficult, no matter which form of agriculture we perform,” he says, “I think that we seriously need to ask ourselves: Is the form of agriculture I practice viable in the long term? The past is no longer telling the story for the future.”

However, vineyards don’t require as much water as crops such as almond, rice and cotton. “A growing issue today is cannabis,” says Dr Jones. “I think it is the largest water hog in the US and it is not getting addressed at all. Nobody is managing or controlling [it]. In a growing season, cannabis uses between 378 to 757 litres of water per 0.45 kg of processed flowers. Three point five grams of cannabis requires seven and a half  litres of water.” Other crops like rice are also much more of a problem than vines; a May 2015 TakePart article said that rice is the most water-intensive crop and the fourth-biggest user of water. In addition, it generates only $374.00 per acre-foot of water (the amount of water needed to flood an acre to a depth of one foot). Vineyards use less water and have a bigger return with $2,470.00 generated for every acre foot. 

So how much water is used to produce a glass of wine? It’s hard to tell. The Water Footprint Network (WFN), a non-profit foundation in the Netherlands, has stated that it takes 110 litres. But Dr Larry Williams from the Department of Viticulture and Enology at UC-Davis disagrees. He says the data compiled by the WFN was based on European vineyards, which tend to have lower yields than many vineyards elsewhere. The calculation is complex because there are many elements to take into consideration, including the method of irrigation, rootstock, spacing of row, type of trellising, water retention capability of the soil, water use for frost protection, and wind speed, just to name a few. Water utilised for production of wine also includes the water used in the winery. 

Dr Williams presented an eight-year study done of the water profile and usage of Chardonnay grown in Carneros. One site he studied was irrigated, while the other was not. In the end, 53.7 litres of water was used for the dry-farm parcel to produce one glass of wine versus 57.9 litres for the irrigated block. Irrigation alone accounted for 24.6 litres of water per glass. Studies he conducted in other Californian regions, with other types of grapes, produced similar results.

Alberto Antonini thinks that indigenous grapes are part of the solution. Dr José Vouillamoz, a Swiss botanist and grape geneticist, agrees. “Indigenous grape varieties have survived various climatic changes over the last centuries,” he says. “The empirical selection by the hand of man of the best suited clones for a given terroir, and the adaptation to abiotic stress by the permanent modification of the expression of DNA (epigenetics) have resulted in indigenous varieties being the most in tune with local pedo-climatic conditions.”

He goes on to say, “With respect to irrigation, indigenous varieties could potentially require less watering than recently introduced varieties, as long as we take enough time to identify the best adapted clones for drought resistance.” Vouillamoz adds that the “combination of indigenous varieties with the right rootstock has recently shown a decrease in water needs of up to 40%.” 

There are still many of these old grapes to be found. Winemaker Miguel Torres has invested more than €12m ($14.2m) since 2008 on research to reduce his carbon footprint. He admits, however, that his ancestral grape varieties project in the Penedès region was not originally linked to climate change. “It was more of a lucky side result, when we found out that some of these forgotten grapes varieties, especially Moneu, were very resistant to drought and heat,” he says.

Final thoughts
As the conference came to a close, participants and audience members agreed that the topic was important and timely. Water is precious and I firmly believe that humans should adapt to nature, rather than ask the planet to adjust for us. Every time I take a glass of water from my tap I feel privileged. Water is precious. If something cannot naturally grow and survive, should we really plant it? It’s a difficult question -- but it’s one that we must debate.
Michelle Bouffard

This article first appeared in Issue 6, 2017 of Meininger's Wine Business International. For more great articles, subscribe to the magazine or sign up for the free newsletter.