Climate Change and Viticulture: Opportunities and Risks

Skye Earley (OMAFRA Summer Student),  Kathryn Carter (Fruit Specialist, OMAFRA) and Stephanie Vickers (Horticulture Sustainability Specialist, OMAFRA)

Climate Change

Climate change is again at the forefront of people’s minds in the Ontario grape and wine industry, after low temperatures experienced in January caused extensive winter injury to vines. Scientific research shows that climate change is occurring in Ontario and the evolution of it will dictate things like management practices, the varieties planted, and the success of Ontario’s existing and emerging wine regions in the future. While there are things grape growers can do to help adapt to our changing climate, there are limits to adaptation, and preventing climate change is really the better option.

How is Ontario’s climate changing?

In Ontario the annual temperature increased by approximately 1.5 degrees Celsius between 1948 and 2008. Researchers are expecting that average temperatures may rise by as much as 3 to 8 degrees Celsius over the next century. These warmer temperatures will result in milder winters, longer growing seasons and a higher frequency of severe weather events such as record-breaking storms, floods, droughts and heat waves (Hewer et al., 2021).  Between 1948 to 2012, an increase of 18.3% of precipitation was recorded across Canada resulting in a wetter climate in all four seasons (Vincent et al., 2018).

What are the potential impacts of climate change?

 Climate change can result in:  

• More frequent and intense heat waves and warmer temperatures
• Increase in extreme and unusual weather patterns (ie. Polar Vortex).
• Changes in the intensity and frequency of precipitation leading to drought conditions and heavier/extreme rainfall
• More frequent and intense wildfires

The impact of climate change on grape production will vary depending on geographical location and climatic conditions.

Can climate change provide opportunities for cool climate grape growers?

While climate change poses numerous risks and threats, there may also be new opportunities for wine grape growers in Canadian cool climate wine regions. Milder winters in some colder grape growing regions in Quebec and Ontario may allow grape growers to begin growing varieties that are less cold hardy (Jones, 2012). Warmer temperatures and increasing growing degree days may provide a lengthened growing season enabling growers to choose varieties that are better suited for intermediate climates (i.e. Merlot, Cabernet Franc, and Sauvignon Blanc (Hewer, 2020)). Cool climate wine regions have potential to benefit from the gradual warming trends, however not without risks and limitations.

What are some of the risks to climate change for cool climate viticulture?

Although it is tempting to think to warmer temperatures as being a good thing, it has a negative impact on the grape industry as well, even in cool climate regions. 

Climate change is projected to bring more variable temperature fluctuations (from warm temperatures to cool temperatures) in the winter, which increases the risk of winter injury in January and February (an example of which was experienced in January 2022, where temperatures plummeted after a relatively mild December).  Temperature fluctuations in spring can also result in increased risk of frost injury impacting grape yields and limiting grape plantings in some wine regions. Climate change also weakens and destabilizes the polar jet stream causing it to dip to lower latitudes bringing polar air farther south resulting in increased risk of polar vortexes like the ones we experienced in 2014/2015.

Figure 1 Flooding in Vineyard

Warmer fall temperatures (as we experienced in fall of 2021) can delay or prevent adequate fall hardening along resulting in loss of cold hardiness (Bélanger et al., 2001) and increased vulnerability to late season frosts. The warmer temperatures during the winter may also create undesirable weather conditions for ice wine production, resulting in delays in harvests and reduced yields.

Warmer temperatures can also impact insect pests resulting in increased overwintering survival, increased number of generations, expanded geographic range, increased risk of invasive insect species and insect-transmitted plant diseases (Skendžić et al, 2021; Jones et al, 2005).

Decreased precipitation may result increased need for irrigation to prevent off flavouring in wines (Reynolds, 2007). While more frequent and intense rainfall increases disease pressure resulting in rising costs for fungicides, and greater issues with rots at harvest. Flooding in vineyards also makes it more challenging to conduct activities in the vineyard needed for production (spraying etc.).

What are the potential impacts of climate change on oenology?

Climatic conditions can have a negative impact on wine quality as well due to accelerated ripening, increasing brix levels and leading to higher wine alcohol content, which is not always ideal and/or marketable. Early ripening also produces lower than ideal acidity levels which prevents wine from obtaining fresh fruity flavours and can have a negative impact on the storability of wine (Shawn, 2016). A change in climate also changes the terroir of the wine and may impact the marketability of the wines. Ontario, a cool-climate wine growing region, has enjoyed a special status as one of the few regions in the New World where Riesling is a signature variety. However, little is known about how our changing climate may impact the aromas and flavouring of this signature variety.

Conclusion

It is clear that climate change will have a significant impact on Ontario’s wine industry. Continuing to be informed about the impact of climate change on grape production and learning about environmentally sustainable and adaptive production practices is an excellent method of combating climate change.

References

Bélanger, G., Rochette, P., Boostma, A., Castonguay, Y., & Mongrain, D. (2001). Impact of climate change on risk of winter damage to agricultural perennial plants. Climate Change Action Fund, Report A084, Agriculture and Agri-Food Canada, pp. 1–65.

Hewer, M. J., & Brunette, M. (2020). Climate change impact assessment on grape and wine for Ontario, Canada’s Appellations of Origin. Regional Environmental Change, 20(3). https://doi.org/10.1007/s10113-020-01673-y

Hewer, M. J., & Gough, W. A. [CK(1] (2021). Climate change impact assessment on grape growth and wine production in the Okanagan Valley (Canada). Climate Risk Management, 33, 100343. https://doi.org/10.1016/j.crm.2021.100343

Jones, G. V. (2005). Climate change in the western United States grape growing regions. Acta Horticulturae (ISHS), 689, 41–60.

Jones, N. K. (2012). The influence of recent climate change on wine regions in Quebec, Canada. Journal of Wine Research, 23(2), 103–113.

Reynolds, A. G., Lowrey, W. D., Tomek, L., Hakimi, J., & Savigny, C. de. (2007, June 1). Influence of irrigation on vine performance, fruit composition, and wine quality of chardonnay in a cool, humid climate. American Journal of Enology and Viticulture. Retrieved August 11, 2022, from https://www.ajevonline.org/content/58/2/217

Shawn, T. B. (2016). Climate change and the evolution of the Ontario Cool Climate Wine Regions in Canada. Journal of Wine Research, 28(1), 13–45. https://doi.org/10.1080/09571264.2016.1238349

Skendžić, S., Zovko, M., Živković, I. P., Lešić, V., & Lemić, D. (2021). The impact of climate change on agricultural insect pests. Insects, 12(5), 440. https://doi.org/10.3390/insects12050440

Vincent, L. A., Zhang, X., Mekis, É., Wan, H., & Bush, E. J. (2018). Changes in Canada’s climate: Trends in indices based on daily temperature and precipitation data. Atmosphere-Ocean, 56(5), 332–349. https://doi.org/10.1080/07055900.2018.1514579

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