A new global study led by researchers from the University of British Columbia (UBC) has revealed that temperatures during the growing season have increased globally across major wine regions. On average, regions have warmed by the equivalent of almost 100 extra growing degree days (GDD), influencing vines’ growth and ripening.
“Europe is feeling the biggest impact, with parts of the continent heating up by as much as 2.5°C since 1980. That kind of change can affect harvest times, grape ripening, and thus the taste of the wine,” said Dr Elizabeth Wolkovich, senior author of the study and an associate professor at UBC’s faculty of forestry.
Unlike previous studies which have focused on a single country or region, and often one grape variety, this study analysed data from winegrowing areas across five continents and considered over 500 varieties. It examined average temperatures, as well as extreme heat, seasonal timing and winter temperatures—offering one of the most comprehensive pictures yet of how climate change is reshaping viticulture.
One of the most worrying trends detected is the increase in the number of extremely hot days (above 35 °C), which can seriously damage grapevines. Parts of eastern and western Europe are now experiencing up to one more of these extreme days per growing season than they were a few decades ago.
“That may not sound like much, but for vines already near their heat limit and for regions in Europe that rarely saw such temperatures before, it’s a big challenge. Regions that are already hot, like northern Africa and western Asia, are particularly at risk,” commented Dr Victor van der Meersch, study co-author and a postdoctoral researcher at UBC. He pointed out that even a small temperature increase can lead to heat stress, water shortages and a higher risk of wildfires, making traditional grape-growing practices harder to maintain.
While the study shows a universal warming trend across the world’s wine regions, it also shows how climate change is affecting different areas in unique ways. Northern Africa and western Asia saw significant increases in average temperatures and growing degree days, but their increase in extreme heat was comparatively smaller. In contrast, southern and western Europe are seeing nearly five times as many extreme heat days as they did in 1980.
Warmer winters and nights are also changing grapevine growth and the timing of key stages like budburst and harvest. The study found that winter temperatures have increased by about 1 °C globally, with Oceania and central and eastern Asia seeing some of the largest changes.
Although many producers are already looking to change the varieties they grow, Dr Wolkovich recognised that this isn’t always easy, especially in regions that rely on a few popular types. “We need more diversity in the grapes we grow. Choosing heat-tolerant varieties helps, but we also need to be mindful of when those grapes grow and ripen. Timing is everything.”
Technology such as soil sensors, satellite imagery and weather stations is also helping growers, but can only go so far. “It’s definitely not the end of winemaking as we know it – but it is a major challenge,” concluded Dr Wolkovich. “The type and quality of wine in our glasses tomorrow will very much depend on what we do in the vineyards today, and especially on the global decisions we make to reduce greenhouse gas emissions.”
