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Viticulture exploiting climate change

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What impact climate change has on viticulture worldwide and how can producers moderate the effects?

Forget what happened in 2012 and 2013. If you want to understand the impact of climate change on viticulture, simply observing yearly snapshots is misleading. Nigel Sneyd, director of International Winemaking at Gallo, argues that “climate change is a along-term phenomenon and people too readily take three-year or at best ten-year trends as unequivocal signs, they should be looking at centuries of data”.

Our climate is naturally variable (some regions getting colder and some hotter) and the change is so slow. Researchers at the University of Southern Oregon carried out extensive research and reported that the average temperature in thirty classic high quality wine producing regions worldwide has risen by 3 degrees in the last 50 years. They also predicted a rise of 2.5 to 4.7 degrees by 2050. Dr Richard Smart, an Australian viticulturist, claimed that just one degree of temperature rise can wipe out an entire grape growing region. However, there is strong evidence that growers are managing to moderate climate change effects successfully through careful vineyard management and location.

For several decades Chilean, Argentinean and South African producers have been taking advantage of unique coastal and altitude conditions that guarantee sustainable production of high quality wines in areas that would otherwise be too hot or arid. Cold ocean currents and cool air coming down from the Andes at night helps to stabilize temperatures and moderate very warm and dry climate with infrequent rainfall.

High temperatures have always been a reality in the Douro. However, Fernando Alves of the Association for the Development of Viticulture in the region warns that “intense exposure to sunlight and repeated periods of drought in recent years have put deep stress on the vine and soil”. One way of tackling this issue is to plant grapes at various elevations. Mr Alves suggests that “one variety that thrives now at 600 meters might be planted at a site 100 meters higher or situated with a different exposure to the sun, and so be coaxed to adapt to its new growing conditions”.

Awareness of climate change on vineyard location is key for sustainable viticulture. For example, on-going research by Prof. Silvia Guidoni of the University of Turin in the vineyards of G.D.Vajra in Piedmont discovered that south facing vineyards that used to have perfect exposure now are too hot in some years. It is west-southwest vineyards that now seem to be more successful as they benefit from the sun taking longer to warm them therefore avoiding reach high temperature exposure.

The way we interact with our environment is directly influenced by climate change. Producers may choose to modify row orientation in order to minimize sunburn. In regions that lack cloud cover, canopy management can be used for better protection and shade with the possibility of overhead trellising. Whereas in cooler climates, open canopy allows required sunlight to reach the grapes and allow full ripeness. For example, in Tasmania, Andrew Hanigan of Derwent Estate chooses to remove leaves at the bottom of the vine in order to reduce methoxypyrazine concentration in his Sauvignon Blanc.

Similarly, delayed pruning encourages delayed budburst, which decreases the risk of spring frost damage. In order to tackle this seasonal damage, Albert Bichot in Chablis uses electric wire in the vineyards and Hattingly Valley, UK sparkling wine producer is experimenting with Frost Guard that can create temperature fluctuation reducing ice crystal formation. In extreme cold temperatures such as in Ontario or Northern China, producers may choose to bury their vines mitigating their bud loss.

By careful selection of clones and rootstocks that are more resistant to extreme temperatures and saline soils, vines can better tackle heat waves or rain storms. Chris Williams of Meerlust in Stellenbosch is experimenting with Paulsen 1103 rootstock for their Merlot as it is better suited to drought conditions and has a very good tolerance to salt.

Adaptation of different grape varieties is also one of the solutions counteracting climate change. For example Touriga Nacional, known for ability to photosynthesize for a much longer period than many other grape varieties, could be planted more widely outside Portugal. Introducing new grape types however could result in a loss of regional character and it may be problematic since many Designated Origin wines are related to the type of grape used. Less restricted areas such as England are already taking an advantage of their freedom. A more Mediterranean climate in southern England has spurred a boom of new plantings of Chardonnay, Pinot Noir and Pinot Meunier which now account for more than 50% of all England’s plantings and are destined for sparkling wine production.

However, for some growers who are short of money following several bad vintages, it may now be too late to act. It is estimated that over 200 Beaujolais producers are in danger of bankruptcy after frost and hail affected the 2012 harvest particularly badly. As a consequence, many are lacking finances to move from the goblet to the trellis system in order to better manage the vines and rely less on chemical fertilizers and pest control.

The impact on the Champagne region is rather more controversial. There are those such as Arnaud Descôtes, environmental manager for the Comité Interprofessionnel du Vin de Champagne, that believe that global warming is a good thing. There is a higher number of released ‘great’ vintages as the average flowering is now earlier due to warmer climate, hence the grapes are ripening earlier (14 days earlier according to CIVC) and therefore they are less prone to poor weather at the end of the growing season. It also allows more vines to be planted in the region. On the other hand, both Chardonnay and Pinot Noir have a very narrow ideal average temperature band during the growing season (Pinot Noir 14-16°C/Chardonnay 14-18°C) and it is likely that any deviation from this range will produce less distinctive wines lacking full-body elegance.

The situation in Piedmont indicates a similar predicament. Whereas rising temperature had a positive effect overall with a string of good to outstanding vintages since 1996 (except 2002) and significant improvement of lower quality Barolo, unpredictable rainfall is causing significant soil erosion. Despite overall rainfall remaining fairly constant, its unpredictable distribution is creating more very dry and very wet periods, with the local silty soil crusts struggling to cope with the extremes.

Philippe Guigal, chief winemaker of Maison Guigal in Rhone is positive but cautious about climate change. He says that there is “a much better correlation between the physiological maturity and the phenolic ripeness of Syrah in the north of the region now”. 25 years ago chaptalisation was a regular procedure but now grapes have a natural potential strength of 13% to 13.5% that is perfectly satisfactory. However, recent research by Conservation International warns that production in the Rhone will decline as warming climate will make it harder to grow grapes here by 2050.

In Bordeaux many producers have also noticed a slow yet significant change in growing conditions. The shift to a compressed growing season is resulting in uneven grape ripening and sugar accumulation, reflecting in unbalanced yield and low-acid wines that lack complexity. It has been proven by recent research by the Grape and Wine Research and Development Corporation (GWRDC) supported by Treasury Wine Estate. Open-top chambers were designed where temperature was increased by 2°C above ambient to represent warming projections for wine growing regions under realistic vineyard conditions. The key finding was that there was a shorter harvest period, putting logistical pressure on producers and directly affecting wine quality.

Luckily, vines are much more resilient to climate change than we give them credit for. However, the recent rapid spread of new pests and disease is a visible sign of warmer temperatures according to Dr Richard Smart. The multi-coloured Asian ladybird that taints wines with methoxypyrazines is already causing problems in Canada, Italy, Spain, France and England now too.

Dr Smart also warns that Esca, a type of trunk disease linked to climate warming, could pose a far greater risk to our viticulture than phylloxera. It has been spreading rapidly in Burgundy, particularly affecting Sauvignon Blanc as the fungal pathogens affect a vine’s vigour and life span through delayed and stunted growth. Louis-Fabrice Latour of Maison Louis Latour confirms that Burgundy is producing less wine now than in the 80s and 90s as a result. However, climate change is only one factor blamed for spreading this disease. Sodium arsenite fungicides, historically used to kill trunk disease, were banned 10 years ago due to their destructive impact on soil. In addition, electric pruning shears are increasingly used which make bigger cuts when cutting the old wood, creating more infection.

To think that in 20 to 50 years, Champagne will be over-shadowed by sparkling wine production on the coast of Scandinavia or that Southern Rhone producers will grow pineapples and mangoes instead of their beloved Chateauneuf-du-pape, seems far-fetched. There is still no visible proof that countries such as Sweden, with its mere 50 hectares currently under vine, are benefiting from any of these changes. In fact, wine production in these countries is still very much in its infancy.

Of importance are increasingly extreme weather patterns and their unpredictability. Hail, frost, storms, snowballs the size of potatoes, sudden rainfalls, heat waves and prolonged droughts have a direct affect on vineyards worldwide. Whereas change of temperatures can create new opportunities while influencing vine physiology, berry composition and wine attributes, extreme weather conditions have severe consequences. Sudden hails storm can ruin a chateau’s annual production in a few minutes.

Burgundy’s new regional association (ARELFA) invested this year in a new technology to protect the region from devastating hailstorms. Spurred by continuous crop loss over the last 15 years, ground generators were developed in order to control weather patterns in the sky. Test already showed 50% success and is more affordable (€10 per hectare) than anti-hail rockets.

South African and Australian producers are used to heat waves and droughts and are very much aware that access to water will become increasingly important. Whereas South African growers lack the scope to move polewards, Australian growers are exploring cooler regions such as Tasmania, already showing great potential for sparkling wine production.

Soil salinity is also a threat in Australia and the use of saline tolerant vines that are able to absorb water will become significant. This problem, caused by imbalance of the hydrological cycle or irrigation, is particularly significant in Western Australia, South Australia and Murray-Darling Basin according to CSIRO, the national science agency.

Water management and the sustainability of water sources is on everyone’s mind. Permitting irrigation where currently appellation laws forbid it for the production of high quality wines (PDO and PGI) is an obvious change that producers are bound to fight for.

It has been estimated that in order to produce a bottle of wine, 1,500 litres of water is used, therefore conserving water for use in vineyards and cellars will be a key factor in water resource planning. Growers will be competing with another as well as (and arguably more importantly) other agricultural areas. Areas such as California are considering enforcing mandatory water restrictions due to 7 years of consecutive droughts and after experiencing one of the driest year’s on record in 2013. The price of irrigation water in Riverland, Riverina and Murray Valley has tripled in recent years and 40% of producers are struggling to afford it. But there are smart vineyard practices that help to balance the cost increase. Bryson Brothers at Morambro Creek in Australia use mulch cover which protects evaporation and saves 20-30% of water.

Dramatic and unpredictable vintage changes harm individual producers much more then the overall average temperature rise. As more extreme weather conditions occur greater vintage variations appear, highlighting the importance of innovative viticultural techniques. To become sustainable, producers will need to better understand their vineyard locations and their water sources. There is much work to be done in the vineyards and the emphasis will shift significantly towards the vigneron’s work alongside the winemaker’s. However, there will be plenty of new opportunities and plantings in new areas, that should hush any warnings of global wine shortages.

 
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Posted by on April 30, 2014 in Uncategorized

 

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