Wine

How climate change is changing our wine

In 2012, a leading Coonawarra viticulturist looked out upon a vineyard in the northern part of the region, a place of shallow soils, home to 25-year-old Cabernet Sauvignon vines. It was a good site, had been a strong performer for his employer Wynns Coonawarra Estate, but now, viticulturist Allen Jenkins decided to see just how robust it really was.

He divided the block in half. For one set of vines it was business as usual. For the other, a harsher new reality was about to set in as he deliberately reduced the amount of irrigated water it would receive for the next three years, just 10 per cent of its normal allowance. When the results were collated, there was nothing but sad news for those parched Cabernet vines.

“Yield dropped for each of those three years by 40 per cent, on average,” says Allen.

“The berry number also dropped, berries were much smaller, there was an increase in colour and tannin, but the problem was you lost some of that Cabernet varietal character.”

Recovery for the vines once water was returned was another big hurdle, it was far from immediate and they continue to struggle to this day.

Cabernet Sauvignon is the flagship grape for Coonawarra, a symbol of its national and international standing in the world of wine, and here it was being stripped of its noble character by a deliberate man-managed climate intended to mimic global warming in all of its nastiness.

Allen had made his point. Climate change was capable of treating even the most celebrated of grapes with disdain.

Now, he’s learning to adapt.

He’s not the only one in the Australian wine industry.

A harsh reality

Between now and the year 2030 the annual average temperature is expected to rise between 0.2ºC and 1.1ºC in many of Australia’s grape growing regions.

By 2050, the projected increase is 0.4ºC to 2.6ºC. A warmer future will go hand in hand with a drier one and one, it is believed, that will be increasingly erratic, throwing up unpredictable extreme weather conditions.

Under this scenario, the annual Australian wine grape harvest will be earlier; grapes coming into full ripeness during the hottest parts of summer, stressing vines.

Some suggest it’s already here.

“Vintage 2015 was our 35th in the region,” says Jeffrey Grosset of Jeffrey Grosset Wines in the Clare Valley.

“We commenced harvest for our two Rieslings (Polish Hill and Springvale) 35 days, almost to the day in both cases, earlier than we did 35 years ago. The suggestion of a (earlier vintage) trend to around roughly one day earlier each year, seems compelling.”

His Clare colleagues at Jim Barry Wines, to the north of his vineyard, had already picked and were fermenting their 2015 Riesling, Shiraz and Cabernet by mid February, a first for them.

What does climate change mean for my wine?

In a warmer climate, vintage will probably be shorter and more compact, which might suit earlier ripeners like Chardonnay, but won’t go down well with late season starters such as Cabernet. The heat that drives sugars up will also force acids down.

A drier season scenario similar to what Allen Jenkins found  with smaller yields and lack of varietal flavour may become a widespread problem. The effect will be more noticeable in inland regions that are expected to be hotter than coastal areas. Australian research suggests grape quality will be reduced nationally by seven to 23 per cent by 2030, and 12 to 57 per cent by 2050.

The fact that climate change is real and not some annoying trend that will eventually cycle off and bring certainty back into our lives, would appear to now be acknowledged by Australian winemakers. And it’s not exclusively about heat.

“Climate change to me is both heat and rain,” says Peter Barry at Jim Barry Wines. “Yes, it’s the unpredictability of the weather, all that is puzzling and a little terrifying.”

Dr Leanne Webb, Climate Projections Liaison Manager at the CSIRO and an academic with more than a decade’s research into the subject, chooses her language carefully when describing the causes behind our changing climate.

“Increasing emissions of carbon dioxide and other greenhouse gases are altering the composition of the atmosphere,” she wrote in her seminal paper, Modelled Impact of Future Climate Change on the Phenology of Winegrapes in Australia (2007). 

“It is very likely that most of the global warming since the mid-20th Century is due to increases in greenhouse gases from human activities.”

For the first time in recorded history, the earth’s temperature is clearly more than 1.0ºC above the 1850-1900 average. Since 1997, which at the time was the warmest year on record, 16 of the subsequent 18 years have been warmer still.

What to do?

Dr Webb suggests Australian wine producers do three things to address its impact on their vineyards: 1. Look to grapevine management techniques, 2. Shift vineyard sites and 3. Think about different grape varieties.

In the Yarra Valley, winemaker Dan Buckle at Domaine Chandon, one of Australia’s leading sparkling winemakers may be locked into the classic Champagne trio – Chardonnay, Pinot Noir, Pinot Meunier – but he is still free to look at different sites.

“I think that by focusing on altitude in vineyard selection we can avoid risks of climate change,” he says. “Certainly the results we see from our Whitlands vineyard are exciting.”

Whitlands is one of the highest vineyards in Victoria, around 800 metres on a high point in the King Valley, and was planted by Brown Brothers in 1982. In 2010, Brown Brothers went in search of parts potentially cooler, buying the extensive Tasmanian vineyards of troubled forestery giant, Gunns Ltd. for $32.5 million. It was an expensive commitment to a changing climate, ironically, coming at a cost: the forced sale of Whitlands.

But not everyone can change vineyard location. It’s far easier and cheaper to change the grape variety.

McLaren Vale boasts a sunny, Mediterranean-style climate. With that in mind, Coriole winemaker Mark Lloyd thought it obvious to look to Italian varieties. Some didn’t work. Nebbiolo and Barbera are real sooks in the heat, as he discovered during the January heat wave of 2009. Fruit all but disappeared on the vine.

However, grape varieties sourced from Southern Italy are a different story. Fiano has become possibly his greatest success story, an inspiration to others. It is already being hailed as making the region’s best white wine. Nero d’Avola, a late maturing red variety, is also performing well. And this year, he has Apulia’s dark-hearted Negroamaro planted.

In the Clare Valley, one of the most surprising alternative grape stars is an unpronounceable Greek variety that originally hails from the fabulous volcanic soils of Santorini. Assyrtiko was brought into Australia by Jim Barry Wines and from its first vintage in 2014, its crisp acid personality was a delight. The grape absolutely thrives in the dry and the hot.

Still, new grape varieties, many with difficult-to-pronounce names, may be trending, but there are others who simply look to adapt what they’ve got. Maybe they’ve read the controversial new book from pioneering Western Australian viticultural scientist, John Gladstones, Wine, Terroir and Climate Change (Wakefield Press) which doesn’t want to be too doom and gloomy about the future. His message? Terroir is resilient.

Others may see hope in new varieties being developed by the CSIRO. Brown Brothers had moderate success with Cienna some years back and are now backing Project Enigma, another first in the wine world, a totally new grape variety that laps up the heat.

Climate change means change. But, if handled with thought and positive action, it could signal an exciting future for winemakers and drinkers alike.