Rising atmospheric CO2 levels and wine quality, and the possibility of artificially-lowered CO2 for viticulture
By Neil Stacey
Elevated CO2 levels increase the growth rate of plants and also modify their morphology. In particular, carbonaceous components of plant matter become more prominent. Studies have shown that elevated CO2 levels result in higher concentrations of soluble sugar in fruit, and also that the ratio of sugars to other molecule types tends to increase. Rising atmospheric CO2 levels can therefore be expected to affect the nutritional and flavour profiles of plants. For most crops this is not necessarily all that significant because the percentage changes are negligible compared to the effects of other changes in farming practice. Wine-making, however, is a finely-tuned process that is highly sensitive to environmental shifts and consequently, it can be expected that rising CO2 levels will have a sizable effect on wine quality, which will be deleterious in most instances. This phenomenon suggests that the novel practice of CO2 restriction, opposite to the common agricultural practice of CO2 enrichment, may be of benefit as a means of maintaining current flavour profiles in viticulture, or even of improving flavour and quality.