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How does Global Warming impact wine production?

How does Global Warming impact wine production?

Wine is an agricultural product, created by farmers and at the mercy of the climate. Climate change is having a wide range of impacts on the global wine industry, from shifting wine regions, changing wine styles, to increased costs. This blog post will take a small look into how it affects production and steps taken to counter it.

Earlier Harvests: With rising temperatures, grapes reach sugar ripeness earlier in the season, but will not reach flavour ripeness until later on. There are two options available. One, harvest earlier when the grapes reach sugar ripeness but before they have reached flavour and tannin ripeness, which potentially gives a lower quality wine. Two, leave the grapes on the vine to accumulate flavour ripeness whilst sugar increases and acidity decreases. This leads to a wine higher in alcohol but lower acidity, a key component of a balanced wine. How are winemakers responding to the challenge? First, planting grape varieties that are better suited to a warmer climate. For example, Bordeaux has recently permitted the planting of 8 new varieties (6 red, 2 white), some found traditionally in Portugal, that are better able to cope with warm, dry conditions. Second, they are looking for cooler sites to plant in spots that previously may have been dismissed as too cold.

Changes in wine styles: wine styles that are dependent on climate are less frequently available in a warming climate. Take two examples. First, Germany and Austria are the traditional home of Eiswein production, but consistently warmer summers and milder winters pose a systemic threat. Grapes ripen too fast in the summer, then it winter it may not get cold enough to reach the -7°C required to freeze the grapes on the vine. Not much can be done to counter this – it’s either cold enough or its not. Winemakers may abandon Eiswein altogether, if winter conditions are consistently too warm, as they are running a serious loss if weather conditions don’t dip cold enough. Second, Syrah in France (also known as Shiraz in Australia) is characterised by its trademark black pepper aromas that is found in cool climates. A warming growing environment may lead to a loss in identity. More broadly, the pressing issue is preventing over-ripe grapes and maintaining freshness in wines, rather than worries over insufficient ripening.

Extreme Weather Events: Mother nature is a powerful force and increases in extreme weather, sometimes out of season, can massively affect the vineyard. Late and un-seasonal frosts can destroy the grapes at early stages of development, freezing the water inside the shoots and causing them to expand and explode. At the other extreme, high temperatures above 40°C will stop the ripening process as the vine shuts down to preserve water, while also leaving grapes susceptible to sunburn. White grapes in particular are susceptible, leading to undesirable bitterness in the wine. Both will reduce the size of the crop and potentially force the producer to increase prices to account for the shortfall, or run at a loss for the year. High temperatures can also lead to droughts and wildfires. Obvious potential damage from wildfires is the destruction of the vines and infrastructure. Less obvious, but a very real economic risk, is smoke taint in the wine from nearby fires. This presents as an unpleasant smoky, burnt or ashy character to the wine that can present over time in a finished wine.

Shifts in Wine Regions: viable wine regions are shifting closer towards the two poles, as regions that were previously too cool to ripen grapes are now sought out for their ability to produce fresher styles of wine. The UK – derided for years as producing low-quality wine – has now arrived as a producer of high quality sparkling wine, with viable vineyards found as far north as Yorkshire. A continually warming climate has led to predictions that UK will be able to produce red wine in the coming years. In Argentina, a region as far south as Patagonia, is now a hot ticket to some exciting cool-climate styles of wine. Germany as a region struggled for many years to soften the famously high acidity of its wines. Now, they can consistently ripen and produce mind-blowing Riesling year on year across the country, and have established a reputation for world-class Pinot Noir.

The other side of this coin is regions that historically were perfectly positioned for grape growing – think warm, dry summers – are becoming too warm and too dry to be viable. Summer temperatures might consistently reach over 40°C, above which the vine shuts down to preserve water and no longer ripens its grapes. Sunburn also becomes a vital issue – the skins are burned and they impart a bitter taste into the wine. Increasingly, drought may become an issue. The vine shuts down to preserve its own water. Irrigation can be a solution. Targeted drip irrigation, where water is dripped (as the name suggests) onto the roots of the vine can target the irrigation in the most resource-efficient way. But in certain cases this might not be possible. The price of water may be too high to be cost effective, as in certain parts of Australia. Or the drought may be so lengthy and water so precious, that it is diverted elsewhere to ‘essential’ functions. In this case, entire vineyards might be lost and the winemaker has no response.

Sustainable farming practices: the last 30 years has seen a big increase in adoption of sustainable, organic and biodynamic practices in the vineyard, in recognition of the impact that intensive agriculture has on the environment. Reducing irrigation where possible, avoiding the use of synthetic chemicals that may run off into the surrounding environment and reducing the amount of ploughing of the soil as this releases CO2 into atmosphere, are all part of an effort to situate the vineyard as a part of the larger ecosystem.

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