Will Good Vintage Wines Grow Ever Scarcer?
Northwest China is becoming both warmer and wetter. Is this good news or bad news for local agriculture?
Many people’s first instinct is that becoming “wetter” must be a good thing for the arid inland Northwest – at least with more water, more crops can be grown. But the impact of climate change on agriculture is much like the butterfly effect: complex and difficult to predict.
Take one of the region’s flagship industries – the wine industry – as an example. More heat and more rainfall are already reshaping the yield and quality of wine grapes. Wine grapes, in turn, are often likened to the “canary in a coal mine”. In the early days, coal miners would carry a canary underground because the bird was far more sensitive to dangerous gases than humans; if the canary was poisoned and died, the miners knew there were lethal gases below and they had to evacuate. Wine is especially sensitive to climatic conditions, and its triumphs and setbacks are a particularly revealing indicator of local climate change – which is why the vintage of a wine matters so much when selecting one, as only the right balance of sunlight, heat and moisture can yield a wine of exceptional quality.
Perhaps, then, the story of wine grapes can offer us a glimpse of the unprecedented challenges now facing agriculture in the Northwest.
The shift towards becoming wetter, however, only began in the mid-1980s. This climatic signal was first detected in 2002 by Shi Yafeng, an academician of the Chinese Academy of Sciences, who proposed that against the backdrop of global warming, most of Northwest China would experience a trend of warming and wetting.
In the two decades and more since, scientists have continued to observe rising precipitation across the region. In recent years, rare extreme rainfall events have drawn considerable public attention. In July 2021, torrential rain sent floods surging through the Taklamakan Desert, inundating an area of more than three hundred square kilometres.
A recently published report by Greenpeace, The Temperature of Civilisation – A Systemic Assessment of the Impact of Climate Change on Ecology, Industry and Cultural Heritage in Northwest China, also concludes that rising temperatures and shifting precipitation patterns driven by climate change are increasing both the frequency and intensity of extreme weather events, posing severe challenges to the ecological stability, agricultural sustainability and material cultural heritage of the Northwest region.
I. Warming: A Double-Edged Sword
Ms Yin explained that grapes are a crop especially sensitive to climate. At certain critical stages of growth, a single weather disaster can devastate yields or wipe out the entire harvest. In the face of unpredictable weather, she said, their most important task now is pre-disaster protection for their crops and post-disaster recovery.
For example, in late April 2020, Zhangye was hit by four consecutive days of low-temperature frost damage, with temperatures plunging as low as minus six to eight degrees. The vines were unable to bear fruit that year, and it would take two to three years for vine vigour to recover. The economic losses ran into the tens of millions of yuan.
In the broader context of the Northwest becoming warmer and wetter, such disasters will likely become more frequent. Li Chao, one of the authors of the aforementioned Greenpeace report, recalled visiting vineyards in Zhangye in April 2022 for a field survey. The growers there were on high alert, bracing for a late frost that could strike at any moment. Piles of timber and cow dung were stacked across the vineyard: if temperatures dropped too far, the growers would light fires to generate smoke and raise the temperature in the vineyard.
“But on the very night we were filming, it snowed in Zhangye town, and fires were already burning in the vineyards outside,” she said. “The viticulture technician told us that severe late frosts causing major losses had already struck several times in recent years. He had managed the vineyard for so many years, yet now he felt he simply ‘didn’t know how to grow grapes anymore’.”
Since the 1980s, warming temperatures, rising accumulated temperature and a lengthening growing season have steadily pushed the suitable zones for wine-grape cultivation further north across China. For regions that were once too cold for viticulture, this is certainly good news, but it also creates management headaches for traditional growing areas. First, during summer – a critical period for vine growth and development – higher temperatures cause grapes to ripen earlier and accumulate more sugar, which in turn changes the taste of the wine: higher alcohol content, but diminished aroma and acidity. Greenpeace found that over the past sixty years, rising effective accumulated temperature during the wine grape growing season has become a key factor limiting grape quality in parts of Jiuquan and the Northwest, and in Longnan. A study from the Ningxia Key Laboratory of Meteorological Disaster Prevention and Mitigation also found that the rising average temperature of the warmest month in the Yinchuan area was detrimental to wine grape quality.
Warm winters, too, are a double-edged sword. Although average temperatures in the Northwest have risen markedly since the 1960s, lifting winter temperatures, the result is also adverse for wine grapes: first, warmer winters favour pest survival during overwintering; second, a mild winter brings earlier bud-break in fruit trees, which in turn makes the vines more vulnerable to late frost.
Yet even in a mild winter, low-temperature frost damage continues to threaten wine grapes.
The late frost disaster that struck Zhangye described above was also felt in the Ningxia growing area at the eastern foot of the Helan Mountains. In March 2018, daily mean temperatures were five to six degrees Celsius above historical norms, prompting the overwintering vines buried in the soil to break bud prematurely. The new shoots that emerged were then killed by a series of frosts in early April. In recent years, late frost has caused reduced wine grape yields in Ningxia in more than forty per cent of years. Li Yuding, a renowned local viticulture expert, has noted in his research that late frost damage has become the second most significant meteorological disaster across most northern regions, after drought.
Greenpeace found that from the year 2000 onwards, the frequency of late frosts in Gansu Province increased sharply. In most of northern Gansu, frost events during the period from bud-break to flowering all rose. The report attributes this mainly to changes in extreme low temperatures: in a warming world, temperature extremes are intensifying – periods of unusual heat and unusual cold are both becoming more pronounced, meaning that hot spells grow hotter and cold snaps grow colder. For instance, between 1961 and 2020, the mean extreme low temperature during the wine grape growing season in Gansu fell at a rate of 0.045°C per decade; between 1991 and 2020, the rate of decline accelerated to 0.14°C per decade. During the bud-break to flowering stage, the downward trend in extreme low temperatures was even more pronounced.
II. Becoming Wetter: Wine Quality Declines
In a report by The Intellectual, Chen Yaning, a researcher at the Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, and director of the State Key Laboratory of Desert and Oasis Ecology, observed: “Although precipitation in the Northwest has increased, the number of rainy days has not risen significantly. Much of the additional rainfall is due to higher intensity in individual events or heavy downpours. And this greater probability of extreme rainfall actually intensifies climatic hazards, raising the risk of both drought and localised flash floods across the Northwest.”
Becoming wetter, moreover, is not necessarily good news for traditional wine-grape growing areas. More rain before the harvest period can cause berries to crack, dilute the sugars within them, and leave grapes more vulnerable to downy mildew. In recent years, the North China Plain and the Northwest have experienced wet summers. For grape growers, nothing is more heartbreaking than watching days of unending rain descend when the harvest is almost within reach – all their labour undone at the very last step. Yinchuan, a major wine-growing area, illustrates the point: data from 1961 to 2015 show that both rainfall and the number of rainy days in the month before harvest (September) have trended upward, which is unfavourable to wine-grape quality.
In truth, it is not only grapes. For crops long accustomed to a dry climate, increased rainfall often brings unwelcome surprises. The Zhiliang Tian ecological farm in Alxa encountered precisely this kind of predicament: last summer, after several consecutive days of rain, the internal and external moisture levels and temperature differentials in the muskmelons grew so great that the fruit split open; a quarter of the crop could not be harvested, and those that were picked had lost sweetness.
III. The Climate Predicament of Wine Grapes: The Whole World, the Same Warmth and Cold
Time magazine once reported on how Merlot, the grape often called the “Queen of Red Wines,” could vanish from Bordeaux, one of the world’s most celebrated wine regions. Rising temperatures over the past few decades have caused grapes in Bordeaux to ripen earlier and accumulate more sugar, and Merlot has been the worst affected.
Winemakers are already working to cultivate new varieties suited to a warmer climate, adjusting viticultural and irrigation techniques, and even scouting new growing areas. In the past, to preserve the distinctive, pure character of Bordeaux wines, French authorities permitted only six red and eight white grape varieties to be grown in the region’s appellations. Yet in 2019, an exception was made: six new varieties were approved to help adapt to climate change.
The book The Earth Doesn’t Care raises the pest problem facing European wine grapes: warming temperatures have expanded the range of the spotted wing drosophila, and the insect is now being found in areas that once had sufficiently cold winters to keep it at bay. It is not only wine grapes that are threatened – other fruits are at risk too. Scientists warn that as temperatures continue to rise, this pest will spread to ever wider regions.
A 2020 study found that, if no action is taken, 56% of the world’s existing wine-grape growing land would be lost at 2°C of global warming; at 4°C, the figure could reach 85%. And according to the latest IPCC report, global temperatures have already risen by more than 1°C since the Industrial Revolution. The World Meteorological Organization announced that July this year was the hottest month in the history of human weather records. Wine, that “canary”, is warning us that if temperatures cannot be brought under control, the delicacies we once savoured may slip ever further out of reach.
Shi Yafeng, et al. “Characteristics and Trends in the Transformation of Northwest China’s Climate from Warm-Dry to Warm-Wet.” Quaternary Sciences 23.2 (2003): 13.
Wang Jing, et al. “Response of Wine Grape Agricultural Climate Resources to Climate Change in the Yinchuan Area at the Eastern Foot of the Helan Mountains.” Agricultural Resources and Regional Planning of China 38.09 (2017): 122–129.
Li Yuding, et al. “Impact of Climate Change on Wine Grapes at the Eastern Foot of the Helan Mountains and Countermeasures.” Chinese and Foreign Grape and Wine.01 (2019): 38–40+43. doi:10.13414/j.cnki.zwpp.2019.01.009.
Li Yuding, et al. “Sustainable Development of the Ningxia Wine Grape Industry.” Chinese and Foreign Grape and Wine.02 (2019): 99–102. doi:10.13414/j.cnki.zwpp.2019.02.022.
Will a Warming Climate Turn Northwest China’s Deserts into Oasis?, The Intellectual, https://zhishifenzi.blog.caixin.com/archives/249094
An Ecological Farm Facing the Challenges of Warming and Wetting in the Northwest, China Dialogue, https://chinadialogue.net/zh/5/99486/
Meet the “new” Bordeaux Wine Grapes, Decanter, https://www.decanter.com/learn/new-bordeaux-grapes-wines-420290/
Morales-Castilla, Ignacio, et al. “Diversity buffers winegrowing regions from climate change losses.” Proceedings of the National Academy of Sciences 117.6 (2020): 2864-2869.
How Climate Change Is Affecting France’s Wine Industry | Time, https://time.com/5777459/france-wine-climate-change/
Edited by: Wang Hao