With few blunt exceptions, global warming and climate change are a reality. To understand the importance and impact of these changes on wine it is necessary to understand the concept of terroir. Terroir can be defined as the complete natural environment in which a particular wine is produced, including factors such as the soil, topography, and climate. As the characteristic taste and flavour are imparted to a wine by the environment in which it is produced, terroir changes will impact the wine’s flavor profile.With few blunt exceptions, global warming and climate change are a reality.
Vines are grown in a wide variety of climatic situations. However, a majority of the major wine-growing regions are located between the 35th and the 50th parallels in the Northern Hemisphere and between the 30th and the 45th parallels in the Southern Hemisphere. Climate is a major factor in wine production and, among environmental factors, climate has a greater impact on vine development and fruit composition compared to soil and grape variety.
The main measurable effect of climate change is a steady increase in temperature. This is observed worldwide, although significant differences in the rate of heating exist from one region to another. The date on which bud break, flowering, and véraison occur is driven by temperature. This relation is so strong that vine phenology can be predicted by models that are based only on temperature. Temperature also affects fruit ripening and sugar accumulation that increases with higher temperature. Certain secondary metabolites like anthocyanins are negatively affected when the temperature increases and grape acidity, in particular the malic acid content, decreases in high temperature.
It is quite easy to model phenology based on predicted temperatures, but predicting grape composition as a result of changing climatic conditions in the years to come is much less obvious. However, it is very likely that the already observed trend in grape composition will continue. Increased sugar levels in grapes yield wines with a higher alcohol level. Wine quality can be impaired when alcohol level is too low but also when the alcohol level is too high.
Climate change is a major challenge for viticulture in the coming decades. In the recent past, wine quality has increased in most wine-growing regions because of higher temperatures and more frequent water deficits while yields have decreased. If the tendency continues, quality might be negatively affected in the near future. Growers need to implement adaptive strategies to continue the production of high-quality wines at economically acceptable yields in a warmer and dryer climate.
The fact is there is a lot you can do at the winery, but when you have a naturally healthy and good grape 90% of all the work is already done.