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bushfires near a vineyard in Victoria
If Australia’s hot summers are coupled with bushfires, winegrowers face the prospect of their crop being tainted by smoke. Photograph: Matthew Smithwick/AAP
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Climate change
Australian
wine under threat from climate change, as grapes ripen early
Wine
grapes ripening up to two days earlier each year, as viticultural
experts warn some traditional varieties may be abandoned in warmer
areas
Calla Wahlquist
Wednesday 17
February 2016 01.57 GMT
Wine grapes in
Australia are ripening between one and two days earlier each year due
to climate change in a trend viticultural experts say could see some
traditional varieties abandoned in warmer areas.
The Victorian wine
industry is partway through what could shape up to be its earliest
vintage on record, thanks to an exceptionally warm spring and warm
summer.
Grape growers are
also experiencing a compressed vintage with typically later-ripening
red grape varieties demanding to be picked at the same time as
earlier varieties such as chardonnay, causing congestion in the
crushing bay as three months of grapes arrive in three weeks.
Snow Barlow,
honorary professor of agriculture and food systems at Melbourne
University, said vintage dates had been shifting forward at a
gradually accelerated rate over the past 30 years and the trend was
set to continue, with grapes ripening an average of seven days
earlier for every degree the climate warmed.
“They clearly are
the canary in the cage,” he told Guardian Australia. “You can say
what you will about climate change but the plants don’t lie, they
just react to what they feel, and they are reacting again.”
A 2011 study by
Barlow’s Melbourne University colleague, Leanne Webb, examined the
vintage records of 44 vineyards, some of which went back as far as
115 years, and found that grapes had ripened at a rate of 1.7 days a
year earlier between 1993 and 2009.
A later study, led
by Webb and co-authored by Barlow, found that change was driven by a
warmer temperatures and lower soil moisture content, even accounting
for an industry-wide shift towards picking earlier to get low-alcohol
wines.
“It does mean that
for particular varieties you really do have to think about moving,”
Barlow said.
“It sounds a bit
ho-hum in some ways but the climate is changing and you really do
have to analyse carefully when you are looking to set up an
agricultural enterprise not only whether this is the place to do it
now but whether this is still going to be the place to do it in 25
years time – whether you are going to have access to the water you
need in 25 years.
SA wine companies
are looking at the Adelaide Hills and thinking well, do we really
have enough water there?
Prof Snow Barlow
“The South
Australian wine companies are looking at the Adelaide Hills and
thinking well, do we really have enough water there?”
The same trends have
been observed in Europe, where records have been kept by generations
of winemakers since the 1500s. The information is a valuable
indicator of climatic change – there is an extensive global dataset
noting the picking dates and, in later decades, the sugar levels, or
Baumé, of individual vineyards.
“Where it differs
a bit in Europe is that for the most part they have probably pushed
the boundaries a bit more than we have but more toward the cool side,
so when you look at Bordeaux or look at Champagne and the worst years
are sort of the cold and wet ones,” Barlow said. “So they’re
talking about it as something that will help.”
In Australia it’s
the opposite effect: warm springs and hot summers can produce
lower-quality wine, and if they’re coupled with bushfires there is,
Snow said, “bugger all you can do” to save the wine being tainted
by smoke.
Damian Sheehan,
chairman of Wine Victoria and general manager of Mount Langi Ghiran
winery in the Grampians about 190km west of Melbourne, said grapes
that ripened quickly risked “decoupling” their sugar and acid
content, which meant they reached the desired alcohol level before
the flavour was developed.
“You have just got
this very, very high (indicative) alcohol content and you want to
make sure that you manage it so that you don’t end up with high
alcohol wines,” he said.
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“You do start
acclimatising and you start knowing what you are going to do to make
sure that the alcohol levels are what you want to produce.”
Sheehan said they
would not know if it was a record early vintage until after the
season ended, but that most vineyards appeared to be picking early.
He said a number of
companies were planting Spanish or Italian reds, rather than
traditional French varieties, to cope with the warming climate.
Others were looking to expand into cooler climates such as Tasmania.
Andrew Weeks,
executive director of Wine Grape Growers Australia, had not noticed
the early trend, saying 2016 was “probably the most un-uniform
vintage I have ever had anything to do with”. His own cabernet
sauvignon vineyard in South Australia’s Riverlands was harvested at
its usual time.
Weeks said climate
change fell behind economic challenges on the concerns listed by most
growers he spoke to who worried about “whether the policy settings
will see them viable in one to two years’ time”.
“If you have got
that sort of time frame, it’s hard to be concerned about what the
climate might be doing in 20 or 30 years,” he said.
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