Vines growing in the Barossa Valley, South Australia. The climate here is currently suited to produce ripe, bold wines, such as full-bodied shiraz. But climate change could soon render the conditions unsuitable.
Credit: AFP
The Hill of Grace vineyard lies in a quiet, out-of-the-way corner of Eden Valley, the hilly region to the east of the Barossa wine zone in South Australia. The vineyard produces what many consider to be Australia's greatest red: the Henschke Hill of Grace shiraz, a wine so revered that the latest vintage will cost you close to A$400 (US$330) a bottle.
The quality is due to a unique combination of factors: the vineyard's deep, sandy loam soils; the extreme old age of the vines (some planted as far back as the 1860s); and the climate — crucially, it's cooler here than down on the Barossa Valley floor.
Viticulturist Prue Henschke is doing her best to protect her priceless inheritance and improve it for her children. She has adopted organic practices in the vineyard — mulching under the vines, and planting native grasses between the rows to retain precious moisture. But there's one important factor she has no control over whatsoever, and that's the climate.
According to a growing body of evidence, in 50 years — perhaps as soon as 30 — the Hill of Grace vineyard may well be too hot to produce a wine worthy of its price tag. The inescapable fact is that grapes ripen earlier in warmer climates, and early ripened grapes simply don't have the chance to develop the extraordinary, subtle complexities of flavour.
"Scary, isn't it?" says Henschke. "This is a mammoth issue for us. The oldest vines at Hill of Grace have survived for 146 years, but now they're threatened by this man-made change," he says. "And I think, well, Hill of Grace is just nine hectares of the whole of Australia. I wonder how many other irreplaceable sites will be affected as things get warmer."
It's a question many others in the Australian, and worldwide, wine industry are asking. Over the last 12 months, the topic of climate change has become a major issue of concern among grape growers and winemakers.
A recent report from the University of Melbourne and Australian government research body CSIRO, unequivocally predicts that "climate change will dramatically alter the growing season for Australian grapes and affect the wine styles produced". It's a forecast that has resonated with grape growers already experiencing unprecedented drought conditions.
An inconvenient truth
"God bless Al Gore," says Richard Smart, a Tasmania-based viticultural consultant who dubs himself 'the flying vine doctor'. "Now, finally, we're starting to see the industry talking about global warming."
Smart has been talking about it for almost two decades; he gave his first paper on climate change and its possible impact on the New Zealand industry in 1988.
"In a lot of ways, you see, the wine industry is the canary in the mine of agriculture," says Smart. "Because wine is based on such a tight interaction between temperature and grape variety, even small changes in temperature can have immediate effects on wine style and quality."
One way of measuring the climate of Australia's 60-plus wine regions is by referring to their mean January temperature (MJT), a measurement which has a direct relationship to wine quality and style.
Coonawarra in South Australia, for example, is considered cool, with a mean January temperature (MJT) of 19.1°C. It is the region's long, cool growing season that is the key to its elegant cabernet and spicy shiraz. The Barossa Valley is warmer, with an MJT of 21.2°C, a climate perfectly suited to producing riper, bolder wines, particularly full-bodied shiraz. And the Riverland, further inland, is warmer still, with an MJT of 22.8°C. Here, the conditions are best for ripening large crops, but the short growing season means that the fruit is lower quality.
"You can see that implications of just a one or two degree change on these regions are bloody enormous," says Smart.
Glass half empty, glass half full
There's more to climate change, of course, than just a change in the weather. It could have knock-on effects, such as higher energy costs, says Jim Fortune, executive director of the Australian government's Grape and Wine Research and Development Corporation, which could seriously impact the cost of shipping wine.
And then there's perhaps the biggest concern of all: the current, deep, debilitating Australian drought, itself possibly exacerbated by climate change. "We haven't had decent winter rains since 1998," says Bruce Tyrrell, a fourth-generation winery owner from the Hunter Valley, New South Wales.
While these signs and predictions seem to cast an ominous shadow over the future of the industry, not everyone is completely negative about the prospects for wine in a warmer Australia.
In the latest edition of the Wine Atlas of Australia, leading wine writer James Halliday suggests that climate change "may not be bad news for the southern-hemisphere wine regions," which, he points out, will probably experience less extreme temperature increases than their northern-hemisphere counterparts.
Halliday argues that global warming could, in the short term, actually benefit Australian grape growers, because higher levels of atmospheric carbon dioxide might "increase the absolute intensity of fruit flavour and colour" in the grapes.
And Tasmania viticulturalist, Smart, is also optimistic. "I don't think it's a crisis," he says. "I'd say it was an opportunity for the industry because the southern-hemisphere producers are going to be affected least, while much of our competition in Europe — particularly Spain and Portugal — will be the producers who will be affected most."
Shocked into action
Prue Henschke sees the threat of climate change as an opportunity for the wine industry to take a leadership role in the community: "We can't just wait for the government to address the issue. I think we can help change attitudes by being a good example ourselves."
Several Australian wine producers have already begun to do that. The large Barossa-based wine company, Yalumba, has been developing its environmental policy for nine years, and in 1999 was the first wine producer — and one of the first agricultural companies in the country — to join the federal government's Greenhouse Challenge program to cut carbon emissions. Cullen Wines, in Western Australia's Margaret River region, has gone even further and claims to be the first carbon-neutral vineyard and winery in the country.
But even if the entire wine industry — or, indeed, the entire country — became carbon neutral overnight, the climate would still continue to get warmer. And as the CSIRO report bluntly warns, "Grape growers will need to adapt."
Some in the industry have been anticipating this for a while. Chalmers Nurseries near Mildura, Victoria, supplies grapevine cuttings to the industry, and has chosen to specialise in so-called 'alternative' varieties — which means anything, essentially, except the 'classic', well-known cultivars such as cabernet, sauvignon blanc and shiraz.
"We've particularly been focussing on grapes from southern Italy, from places like Campania and Sicily," says Rod Capon, nursery manager at Chalmers. "If and when climate change happens, the industry will need vine varieties that can grow well in a hot climate, that need less water and still ripen grapes with good flavour, that hold good acidity.
All of which sounds fine on paper, but could be difficult in reality. "The problem," says Yalumba's chief winemaker, Brian Walsh, "is that while these obscure, strange-sounding grapes might be more appropriate, they could be very hard to sell to essentially conservative wine drinkers. But it's a challenge we're prepared to have a crack at."
Should I stay or should I go?
According to Richard Smart, staying put won't be an option for some, such as the huge vineyards along the Murray River near Mildura and known as the 'engine room' of the industry because it supplies so much wine.
"It's particularly here in the hot regions of Australia where we're going to have real problems," says Smart. "Some of those regions already have an MJT of 24.5°C. You add two degrees on top of that and it goes over 26°C. You can only grow table grapes or raisins at that kind of temperature. The mind boggles." The answer may be to move, he says.
Prue Henschke doesn't intend to move, though. Instead, she's adapting to anticipated changes. This process started in the early 1980s, when she established another vineyard at Lenswood, in the much cooler Adelaide Hills — a far-sighted move that could well pay off handsomely in the near future.
More recently, Henschke has also planted late-ripening, heat-loving red grape varieties such as grenache and mourvèdre at her other Eden Valley vineyards, something she wouldn't have dreamed of doing 10 years ago.
At Hill of Grace, though, it's a different story. "We've done all we can do," says Henschke. "Now we just have to wait and see how long those old vines can survive."
Max Allen is a celebrated wine writer and author, and a contributor to COSMOS's sister title, G, Australia's green lifestyle magazine, where this article first appeared.
