By Sandrina A. Heleno; Isabel C.F.R. Ferreira
Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal.
Laboratório Associado para a Sustentabilidade e Tecnologia em Regiões de Montanha (SusTEC), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal.
Climate change, a global issue, is receiving increasing attention due to its wide-ranging effects on ecosystems and industries. Among the industries most impacted is viticulture, especially in regions famous for wine production, like Portugal, that has a rich history in winemaking, being this industry a fundamental part of its cultural and economic marks. However, rising temperatures, changes in rainfall patterns, and more frequent extreme weather events are presenting serious challenges to the future of Portuguese wine production.
Climate Change and Rising Temperatures
In Portugal’s famous wine regions, such as the Douro, Alentejo, and Dão, climatic conditions have traditionally been ideal for producing exceptional wines. However, as global temperatures increase, these viticultural regions are experiencing warmer conditions.
The rise in average temperatures has significant consequences for the wine industry. Grapevines thrive within a specific temperature range, typically between 12°C and 22°C. As temperatures climb, grapes ripen more quickly, leading to higher sugar levels and lower acidity. This shift affects the balance of flavors in the wine, potentially producing wines with more alcohol and less freshness, particularly problematic for certain styles like Vinho Verde and cooler-climate reds.
In regions such as Alentejo, where summer temperatures can already surpass 35°C, the warming trend is pushing grapes to their limits. Known for producing powerful red wines, Alentejo could face difficulties maintaining the delicate balance of tannins, acidity, and fruitiness. Over-ripening due to excessive heat can lead to wines that are overly concentrated, losing some of the refinement that characterizes premium vintages.
Precipitation Variability and Water Stress
In addition to rising temperatures, climate change is also disrupting rainfall patterns throughout Portugal. The country already experiences a Mediterranean climate, characterized by hot, dry summers and mild, wet winters. However, projections suggest that rainfall will become more unpredictable, with longer droughts punctuated by intense rain events.
Water stress is becoming an increasingly serious problem for winemakers in regions like Alentejo and Douro, where summer droughts are intensifying. Excessive water stress can slow vine growth, reduce yields, and lower grape quality. During the ripening phase, a lack of water may cause the grapes to shrivel, leading to overly sweet and unbalanced wines. Conversely, heavy rainfall during key periods such as flowering or harvest can also damage crops. Too much rain encourages diseases like mildew or rot, which can ruin vineyards and degrade grape quality. Excessive moisture during harvest can also dilute grape sugars, resulting in wines that are lighter and less structured. Thus, the growing unpredictability of precipitation presents a significant risk to the quality and consistency of Portuguese wines.
Extreme Weather and Vineyard Vulnerability
Another major aspect of climate change affecting Portuguese vineyards is the increasing occurrence of extreme weather events, including heatwaves, storms, and hail. These events can cause severe and immediate damage, sometimes wiping out entire crops in one blow. Heatwaves during the growing season can scorch grapevines, leaving sunburned fruit unsuitable for wine production. Meanwhile, hailstorms which have become more common in certain regions can strip vines of leaves and grapes, leading to reduced yields.
In the Douro Valley, a region famous for its Port wines, the steep terraced vineyards are particularly vulnerable to intense storms. Heavy rains can cause soil erosion, washing away crucial nutrients and topsoil that grapevines rely on. Additionally, strong winds can damage trellis systems, increasing the physical toll on the vineyards. For small producers, the high cost of repairs and the potential loss of an entire season’s harvest can be devastating, threatening the economic sustainability of traditional family-run vineyards.
Adjusting Grape Varieties and Vineyard Practices
As climate change progresses, Portuguese winemakers are adopting various strategies to adapt, including switching to grape varieties that are more resilient to heat and drought. Portugal has native grape varieties, many of which have adapted to the country’s diverse climates over the centuries.
Varieties like Touriga Nacional and Aragonez are more drought-tolerant and can thrive in hotter regions like Alentejo. On the other hand, grapes such as Alvarinho, which prefer cooler and wetter conditions, may find it harder to adjust to the increasingly warm and dry climate in northern regions. Some vineyards may need to consider replanting with more resilient grape varieties, although this is a costly and time-intensive process.
In addition to changing grape varieties, winemakers are implementing new viticultural practices to cope with climate-related challenges. For example, canopy management, pruning vine leaves to provide shade can help protect grapes from excessive sun exposure. Moreover, more efficient irrigation techniques, like drip irrigation, are being adopted to conserve water and ensure that vines get the hydration they need during droughts.
Economic and Cultural Impact
Wine production is a major contributor to Portugal’s economy, both in domestic markets and exports. Climate change threatens to reduce yields and alter wine quality, putting the economic future of many vineyards at risk. Small, family-owned wineries, which make up a large proportion of Portugal’s wine industry, may struggle to meet the rising costs associated with climate change, such as increased water usage, vineyard replanting, and more labor-intensive management practices.
Beyond economics, climate change poses a cultural threat as well. Wine is deeply ingrained in Portuguese culture, and the potential loss of traditional wine styles would be a cultural blow. For example, Vinho Verde, known for its light, fresh, and slightly effervescent character, could become harder to produce in a warming climate. Similarly, the aging potential of Port wines may be compromised if the balance between acidity and sugar is altered by rising temperatures.
Conclusion
Climate change is already significantly impacting Portugal’s wine industry, with rising temperatures, changing precipitation patterns, and more frequent extreme weather events threatening both the quality and quantity of wine production. While winemakers are exploring ways to adapt, such as switching grape varieties and adopting new vineyard management techniques, the challenges posed by climate change are likely to intensify in the coming years. Portugal’s ability to sustain its wine industry will depend on continued innovation in viticulture and broader efforts to mitigate the global effects of climate change.