Point of View

There is no doubt that climate change is creating concern when it comes to the future of grape and wine production worldwide. As I write this, I have just read about climate scientists agreeing we will surpass the +1.5C target and we are likely on track for +2.5C by the end of the century. I also presented online this week about cultivar change as an adaptation strategy to climate change at a symposium run by Washington State University, where growers have already made shifts in their cultivars and are implementing strategies to mitigate heat stress.

So what has been going on with our New Zealand climate recently that may affect our grape and wine production?

• Three out of four of the most intensive coupled ocean-atmosphere heatwaves on record have occurred in the past seven years: 2017/18, 2018/19, and 2021/22.
• These heatwaves have corresponded to average increases of +1.2 to +1.4C in air temperatures over land and sea surface temperatures.
• Interestingly, two of the seasons (2018/19 and 2021/22) were La Niña years.

At the Southern Pinot Noir Workshop, I spoke specifically about climate change and Pinot Noir production. Scanning the news headlines on this topic, you can find the following impacts outlined:

• Harvest a couple of weeks earlier.
• Opportunity to grow in new areas and develop new flavours.
• Frost, wildfires, water shortage, flash floods, hail, extreme temperatures.
• Not all regions are equal in terms of the effects we may see.
• The next big grape - Chardonnay in Central Otago?

As much as I like a good Chardonnay, and as much as the variety may suit Central Otago, these broad-brush statements lack the granularity needed to truly understand the consequences for Pinot Noir production.

So what do we know about Pinot production when modelled for future climate scenarios?

• We project that Pinot Noir flowering may advance between two to three weeks in our key growing regions under a +4C scenario by the end of the century.
• Projections for the time to a target sugar concentration (the example given of 200g/L) in most current Pinot growing regions in New Zealand will advance by three weeks or more.
• We can characterise the current window when Pinot Noir in Marlborough reaches 200g/L sugar. Under all climate change projections, even those projections in the more modest range of 0.3C to 1.7C by the end of the century, this target will advance outside of the current window.
• The results for these projections was at a 0.05° x 0.05° resolution and we can see that within a region there will still be great variability. This emphasises the need to continue improving on this downscaling component to truly understand changes at the vineyard level.
• Controlled temperature chamber experiments with elevated temperatures (30/15C day/night compared with 22/15C day/night) applied at veraison have confirmed increases in sugar concentrations. Composition parameters important for quality also changed: anthocyanins decrease with increased temperature and a range of amino acids increased, which are important compounds for wine quality. For example, increased proline can increase perceptions of sweetness, viscocity and flavour while reducing astringency and bitterness.

While this temperature-driven information is a great start, when it comes down to working out how climate change may shape Pinot Noir production, we need to bring together a multitude of factors such as temperature and water deficit (drought context) to deepen our understanding. However, without starting by characterising them individually, it becomes difficult to tease out what is driving what. We also need to consider adaptation strategies that might in part negate these advances, such as canopy management and form, canopy cooling, and delayed pruning.

So is there much to do? Searching a science database for "Pinot Noir climate change", I uncovered 155 scientific articles, a small quantity relative to the 2,557 available when searching "grapevine climate change". No, I haven't read them all (yet), but there is certainly more to discover, experiment and communicate so we can continue to make informed decisions for managing Pinot Noir in the future.

It was a privilege to attend the conference and be involved in tastings of the latest vintages. We are onto a good thing. Let's keep measuring and modelling so we can manage to retain these superstar Pinots long into the future.