The 2020 vintage was one of the most difficult for winemakers in recent years. The devastating bushfires wreaked havoc throughout south-eastern Australia, with harvest volumes reduced by hundreds of thousands of tonnes. Smoke also played its part, but the underlying cause was more fundamental.
Drought had not only left vineyards ripe for the danger posed by bushfires but also reduced the amount of fruit that grapevines could carry to harvest. At Henschke’s Lenswood property, the ground was parched thanks to only 700ml of rain in 2019 turning the usually plush green scrub a sunburnt brown. When the fires came, there was nothing to stop them decimating the vineyard. For areas not hit by fires or smoke, yields were also sharply down across many regions.
Water shortages will not only reduce yields and increase fire risk over the short-term, they will also make some wine regions unsustainable, forever changing the global wine landscape. Most Australian regions are already dry by global standards. While Bordeaux, Burgundy and Barolo regularly receive more than 400ml of rain during their growing seasons, the long-term averages for the Barossa, Frankland River and Swan Hill are close to half that figure.
Combined with unpredictable flows in the Murray-Darling system and with rising salinity issues, drought and water supply are potentially the biggest challenges facing the Australian wine industry. Compared with other agricultural industries, the wine trade is particularly susceptible to the impacts of a hotter, drier climate. Livestock can be moved to chase better pastures, as can annual crops, however, this is not an option for grapevines. Vines need at least 10 years in the ground for the production of premium wines.
While drought-resistant varieties can be grafted onto old rootstocks, it still takes years before the vines are producing at full capacity. Meanwhile, some varieties, such as pinot noir, have high water requirements that may curb where they can be grown.
It is clear that the local wine industry needs to prepare for a world with lower and less predictable rainfall. Already winemakers and viticulturists have a range of tricks to collect, recycle and protect water. For winemakers in Western Australia’s Great Southern region, water supply has always been a challenge, and vineyards are sometimes matched by vast areas of land solely used for water catchment. Taylors Wines in the Clare Valley is one of many wineries working hard to be more efficient in its water use. The winery recycles 100% of waste water, which, with stormwater capture, helps minimise use of the local supply.
But recycling in the winery is only part of the picture with great gains to be made in the vineyard. The choice of variety and rootstock can make a significant difference, with the traditional French grape varieties native to high rainfall regions not always best suited to the drier Australian climate. Grenache and mourvèdre are generally better choices in drier conditions than, say, pinot noir and cabernet sauvignon.
Annual operations in the vineyard can also have a significant effect on water retention. Mildura’s Duxton Vineyards use a number of strategies to preserve soil moisture. Cover crops are employed to reduce evaporation and overall water use. In addition, soils are kept healthy through the addition of composts that also provide better water retention. Inventive irrigation strategies, such as partial root zone drying, can help reduce irrigation use as well as help protect wine quality and volumes.
Vintage 2020 was in some ways another wake-up call to illustrate the long-term impacts of a drier climate on wine volume and quality around Australia. Water issues will change
not only wine production and how fruit is grown, but also what is on our kitchen tables. Phylloxera changed the wine industry forever. Water challenges brought on by climate change will likely do the same again.