Study finds Cabernet Sauvignon may fare better in high CO2 future

A new study from researchers at San Diego State University and the University of California offers fresh insights into how two of the world’s most significant grape varieties — Cabernet Sauvignon and Chardonnay — respond to elevated CO2 and water stress. The post Study finds Cabernet Sauvignon may fare better in high CO2 future appeared first on The Drinks Business.

Mar 10, 2025 - 11:29

Study finds Cabernet Sauvignon may fare better in high CO2 future

The wine world is no stranger to climate change. With atmospheric CO2 concentrations surpassing 427 ppm in 2024 and likely to reach 700 ppm by the end of the century, viticulture faces a future where rising temperatures and water scarcity will dictate how vines grow, how wines taste and which regions remain viable for grape cultivation. Cabernet Sauvignon grapes on rootstock

A new study from researchers at San Diego State University and the University of California offers fresh insights into how two of the world’s most significant grape varieties — Cabernet Sauvignon and Chardonnay — respond to elevated CO2 and water stress.

Elevated CO2 and water deficit

The study examined how Cabernet Sauvignon and Chardonnay performed under controlled conditions of both ambient (410 ppm) and elevated (700 ppm) CO2 levels, coupled with either well-watered or gradually imposed water deficit treatments. Key physiological responses — such as leaf gas exchange, intrinsic water use efficiency (iWUE) and whole-plant evapotranspiration — were monitored to determine how these grape varieties manage water and carbon intake in a warming world. The results? While both varieties improved their water use efficiency under high CO2 and drought stress, Cabernet Sauvignon showed greater resilience, maintaining higher iWUE and more stable photosynthetic performance than Chardonnay. In essence, the Bordeaux stalwart appears better suited to endure a future with less water and higher atmospheric carbon levels than the popular Burgundian white.

Vineyard management

One of the most striking takeaways from the study is that elevated CO2 led to reduced stomatal conductance — essentially, the vines lost less water through their leaves. Chardonnay, however, exhibited greater stomatal sensitivity, suggesting it may be more vulnerable to fluctuating water availability. For growers, this means that variety selection will be increasingly important in regions experiencing water stress. Cabernet Sauvignon’s ability to maintain higher water use efficiency under drought conditions suggests it may be the safer bet for future plantings in warmer, drier climates. Meanwhile, Chardonnay’s heightened sensitivity raises questions about its long-term viability in traditional growing areas like California and Burgundy without significant irrigation interventions.

Wine quality

The findings also touch on the delicate balance between vine stress and grape quality. While moderate water deficit is known to enhance grape concentration and complexity, excessive stress can reduce yield and alter berry chemistry in ways that may not be desirable. Elevated CO2 levels have been shown in previous studies to influence sugar accumulation and acid retention, potentially altering the aromatic and structural profiles of wines. If Cabernet Sauvignon thrives in high-CO2, water-limited conditions, its wines may retain better balance in the future. However, if Chardonnay suffers more under these conditions, it could require new viticultural techniques — or alternative growing sites — to maintain its trademark elegance and freshness.

Adaptation and sustainability

Beyond variety-specific implications, this study highlights the broader challenge facing the wine industry: how to adapt to increasingly erratic climatic conditions while maintaining quality and sustainability. From drought-resistant rootstocks to canopy management techniques that mitigate excessive heat, viticulturists will need to rethink traditional practices. As CO2 levels rise, vineyards may also need to adjust irrigation strategies, particularly for varieties like Chardonnay that show higher transpiration rates under ambient conditions.