Climate change is real. And it will hit wine hard…

Back in June, I set about writing an article for National Liquor News that was meant to be a roundup of what’s happening in several key South Australian regions. A few conversations with producers to see what was selling well. Simple stuff.

But what started out as a lay-of-the-land report instead served to remind, yet again, that we’re currently facing an existential threat to wine quality. That climate change is the single biggest challenge for wine this millennium.

Sound like hyperbole? Hear me out.

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Grapevines are incredibly sturdy – they can withstand cold down to -20C and still photosynthesise at up to 35C (and survive beyond that). They’re hardy. And adaptive. But at key times in the year, grapevines are highly vulnerable to weather events – particularly at budburst, flowering and just before harvest. Stresses during these periods (through frost, heat, excess winds, hail etc), can directly influence the ability of vines to produce healthy grapes and good yields. And healthy grapes/yields means fine wine.

Research by the AWRI, in particular, has shown what an increase in temperature in the leadup to harvest can result in profound differences in fruit composition – with higher pH and lower acidity, decreased yields and more sugar accumulation at the expense of anthocyanins.

In other words, less healthy grapes, that are sweeter, with less natural acidity and less natural tannins – aka lesser quality.

More dangerously, climate change brings the growing season further back in the year and outside of ideal times. So budburst in regions like Burgundy has shifted from the benign warmth of April into the dark and cold of March, profoundly increasing frost risks for fragile buds. Ditto the move to harvests in the heat of August, with a heightened risk of summer heatwaves damaging bunches and sunburning grapes.

This isn’t a ‘someday soon’ notion either, as we’re seeing harvest dates change dramatically right now. Here’s a a few choice tweets from winemakers to demonstrate:

We are picking 5 weeks earlier in Bendigo than 20 years ago. It’s the rapidity of the change that’s the most glaring. Also talked to a group of travel writers recently they said it does not matter where they go in the world rapid climate change is part of the conversation!

— Tony Winspear (@TonyWinspear) July 27, 2019

yes I concur. Our home block will be 40 this year and we have had 3 of earliest harvests ever in last 5 of that 40. Lots here would be 3 to 4 weeks earlier now than 15 or 20yrs ago

— Anna Flowerday (@TeWhareRaWines) July 27, 2019

And the negatives are already being felt too. In Switzerland recently vignerons in Bündner Herrschaft recounted to me that the record 2018 vintage – the warmest and earliest harvest on record in Switzerland – had introduced challenges that have never seen before. Suddenly, they noticed that vines on the higher, harsher slopes at the tops of vineyards started to experience water stress and lose all their leaves, the grapes then shrivelling on the vine.

Swiss vineyards – climate challenge or opportunity?

We’re talking about Switzerland, which is the very definition of cool (and moist) climate viticulture, now facing the need for irrigation to keep vines alive, even though Swiss vignerons have no water infrastructure of any kind (as they’ve never needed it before).

Indeed it is these cool, old-world regions where climate change will be most acutely felt. Regions where vines have enjoyed a dry-grown stasis for millennia, yet now are struggling with changes that have only occurred within the last few decades.

Of course, there is a silver lining for climate change in some regions. Like the UK, for example, where a marginal climate is now much more appealing. Data, for example, shows that heat degree days (a key metric for working out conditions during the growing season) in Gusbourne (UK wine ground zero) has shifted from 850 to now circa 1100 – ie not far off the long term average of Champagne. Or indeed Switzerland, as many of the aforementioned 2018 wines are the best ever, purely because so many sites could finally ripen grapes perfectly.

Globally, regions can adapt too. Bordeaux has now allowed the heat-tolerant Portuguese grape Touriga to be planted. In warmer regions, we’re seeing more attention to canopy management (to manage shading and protect from sunburn) and cover crops (which have been proven to reduce heat), along with changes in varieties, rootstocks and clones to manage heat.

But right now, the challenges are stark. And Australia is at the pointy end of it.

In the Barossa, for example, 2019 was a case of irrigate or perish. I mean that literally, as the hottest, driest January on record delivered a growing season that pushed vines beyond heat stress and into vine shutdown, with resulting drops in yields (up to 70% in some vineyards) and a drop in quality (I heard from one well-known Barossan winemaker today who won’t be releasing any premium reds out of 2019. He’s not alone).

I have no doubt some will read these anecdotes (want more? Read Max Allen’s article here) and give me some sort of tinfoil hat-esque retort about a lack of data, that the world has been hotter before, resort to personal attacks etc etc and ignore these warning signs. But all it takes is a chat with a few grapegrowers and winemakers to realise that the horse has bolted – climate change is here and it poses massive problems for the wine industry, let alone humanity as a whole.

As Dudley Brown of Inkwell Wines said to me recently this isn’t just a problem for the future either:

‘2019 has changed our mindset to anticipating and actively planning for more 2019s. A lot more 2019s. The game has changed fundamentally. The inflection point is undeniable now’