Climate change is here to stay: adapting vineyards to a warming world

Introduction

As an industry that thrives more on, but may also be more affected by, vintage variation and regionality than any other agricultural enterprise, grape and wine production is ever more being impacted challenged by climate change. Though the gradual increase of CO₂ in the atmosphere lies at the root of our changing climate, the associated changes in temperature and humidity arguably pose the greatest challenges to grape growers. In many regions, soil moisture is decreasing while rising temperatures are increasing both the plant water demand and the heat stress during the growing season (Green, 2024). Though winter temperatures are on an upward trend as well, the risk of winter freeze and spring frost damage persists. Therefore, grape growers face climate-related production challenges and threats throughout the year. One consequence of the global warming trend is the exploration of grape production in previously unsuitable, or marginally suitable, areas further from the equator and at higher elevations (Fraga et al., 2016; van Leeuwen et al., 2024). This trend is taking advantage of the overall lengthening of the growing season (defined as the frost-free period) and the increase in seasonal heat summation (measured as growing degree days), weighed against the availability of suitable land and other resources and the risks imposed by unseasonable temperature fluctuations. In established grape-growing regions, growers might also consider planting on sites with different slope aspects to exploit mesoclimates with less direct solar exposure. Of course, moving to a new location is not an option for growers in existing vineyards, who instead must adapt by using alternative means to mitigate the perceived adverse effects of climate change.

Successful adaptation and mitigation requires decisions to choose from and implement a set of alternative or complementary choices either when replanting a vineyard or when extending the lifespan of an established vineyard. Replanting choices may include changes in scion or rootstock cultivars, planting density, row direction, trellis design, training system, or potential irrigation need (Naulleau et al., 2021). Once a vineyard has been established, cultivars may be grafted over, the trellis design and training system can be somewhat retrofitted, irrigation can be added (provided water is available) or altered, and additional choices concern vineyard floor or soil management, pruning strategy and seasonal canopy management, crop load management, harvest timing, and how to control emerging or changing pests and diseases. In any case, vineyards are costly to establish and take years to reach a positive return on investment, and then growers must ensure continued vineyard profitability for decades. Such economic considerations paired with market uncertainties and growing labor constraints mean that the aforementioned choices cannot be made by considering climate change in isolation, but must also integrate decisions regarding mechanization and automation (Kurtural and Fidelibus, 2021). This presentation builds on our current knowledge of grapevine biology and recent advances in viticultural practices to discuss possible adaptation strategies that growers may use to mitigate climate change effects.