Research: Climate Change, CO2 Levels

Bindi M., L. F., and F. Miglietta (2001). “Free Air CO2 Enrichment (FACE) of grapevine (Vitis vinifera L.): II. Growth and quality of grape and wine in response to elevated CO2 concentrations.” European Journal of Agronomy 14(2): 145-155.

A FACE (Free Air CO2 Enrichment) experiment was carried out on Grapevine (Vitis vinifera L.) in 1996 and 1997 in an existing vineyard in Italy. Four FACE arrays were used to fumigate adults plants, while two arrays were used as control. Three CO2 exposure levels were used in these arrays (ambient, 550 and 700 mol mol-1). Dynamics of vegetative and reproductive biomass and grape quality compounds (sugar and acid concentrations) were monitored during the two growing seasons. Chemical analyses of the main wine quality compounds were made after fermentations. Elevated atmospheric CO2 levels had a significant effect on biomass components (total and fruit dry weight) with increases that ranged from 40 to 45% in the 550 mol mol-1 treatment and from 45 to 50% in 700 mol mol-1 treatment. Acid and sugar contents were also stimulated by rising CO2 levels up to a maximum increase in the middle of the ripening season (8- 14%); however, as the grapes reached the maturity stage the CO2 effect on both quality parameters almost completely disappeared. Wine quality was not significantly affected by elevated CO2. Furthermore, no significant differences were detectable among the plants grown in the two enriched treatments (550 and 700 mol mol-1), and the effects of elevated CO2 concentration were similar in the two growing seasons. The absence of any further stimulation of the highest CO2 treatment (700 mol mol-1) on grapevine growth and yield quality (i.e. grapes and wine) may be explained as a result of transport and/or sink limitations. We can conclude that the expected rise in CO2 concentrations may strongly stimulate grapevine production without causing negative repercussions on quality of grapes and wine.

 

Eysberg, C. D. (1987). “Viticulture in California: Cool airconditioned valleys as the equivalent of warm sheltered “côtes”.” Geo Journal 15(4): 367-373.

This essay focuses on the distinctive geographic setting of viticulture in California. It assesses the significance of the prevailing environmental conditions for wine growing in California and offers an explanation of the spatial pattern of Californian wine climate regions. Wine varieties in California, as almost everywhere in the world, are of European origin (Vitis vinifera). The ultimate result of a bio-geographic diffusion process of Vitis vinifera was the development of superior wine varieties in a climate that is marginal for wine growing in Western Europe (Cf- Köppen). Nestled in a cooler and more precarious macro-climatological environment, the relatively warm micro climates of the slopes (cotes) allow wine growing. The noble varieties peculiar to the slopes have been successfully transplanted in California’s coastal valleys, this not-withstanding the California environment, which is diametrically opposed to that in Western Europe. In a hot macro environment (Cs-Köppen), high-quality wine growing is only possible due to the cool air-conditioned micro climate in the valleys.

 

Jones, G., M. White, O. Cooper, and K. Storchmann (2005). “Climate Change and Global Wine Quality.” Climatic Change 73(3): 319-343.

From 1950 to 1999 the majority of the world’s highest quality wine-producing regions experienced growing season warming trends. Vintage quality ratings during this same time period increased significantly while year-to-year variation declined. While improved winemaking knowledge and husbandry practices contributed to the better vintages it was shown that climate had, and will likely always have, a significant role in quality variations. This study revealed that the impacts of climate change are not likely to be uniform across all varieties and regions. Currently, many European regions appear to be at or near their optimum growing season temperatures, while the relationships are less defined in the New World viticulture regions. For future climates, model output for global wine producing regions predicts an average warming of 2 ◦C in the next 50 yr. For regions producing high-quality grapes at the margins of their climatic limits, these results suggest that future climate change will exceed a climatic threshold such that the ripening of balanced fruit required for existing varieties and wine styles will become progressively more difficult. In other regions, historical and predicted climate changes could push some regions into more optimal climatic regimes for the production of current varietals. In addition, the warmer conditions could lead to more poleward locations potentially becoming more conducive to grape growing and wine production.

 

Neilsen, D., S. Smith, W. Koch, G. Frank, J. Hall, and P. Parchomchuk (2001). “Impact of climate change on crop water demand and crop suitability in the Okanaga Valley, B.C.” Technical Bulletin.

 

Schultz, H. R. (2004). “How may climate change affect viticulture in Europe?” Ace Revista de Enologia, from http://www.acenologia.com/ciencia59_04eng.htm.

Global climate change has been a public discussion topic for several years. It is difficult to predict changes in climate and sea level due to the enhancement of the so-called greenhouse effect (including temperature rise, CO2 increase, and nitrogen deposition) but atmospheric CO2 concentration is measurably increasing and is expected to double current levels during the next century with marked effects on current agroclimatic conditions. Man has effectively accelerated global respiration about 10 million! times by the combustion of several billion years worth of accumulated photosynthate and other organic carbon in the course of a few hundred years. Aside global warming, shifts in rates and distribution of precipitation and increases in surface level ultraviolet (UV)-B radiation due to a depletion of the stratospheric ozone layer are among the likely alterations. Since actions and interactions of climatic factors and man-induced changes in for instance vegetation structure are very complex and oceans can act as large buffers on more radical short-term (years) changes, there is great uncertainty about what to expect over the next century. In contrast to research on natural terrestrial ecosystems and some agricultural crops, possible effects of a change in climate on grapevines have largely been ignored.

 

Stock, M., F.W. Gerstengarbe, T. Kartschall, and P.C. Werner “Reliability of Climate Change Impact Assesments for Viticulture.” International Society for Horticultural Science.

Current Assessments of climate change effects on viticulture are primarily based on global climate models. With respect to temperature and temperature-based indices, this may produce reasonable first approximations. Recent studies indicate that several viticultural regions may become more successful, and others less so, as high-quality wine production area. However, it is not only average temperature but also a variety of other climate parameters and their variability that the allocation of chances an drisks in impact assessments depends on. in this respect, global model resolutions are of limited value. However, current methods of regionalizaiton by statistical down scaling or embedded regional climate models also show deficiencies and uncertainties. This paper presents a new method for the evaluation of regional climate scenarios using the statistical regional model STAR. This model offers improved applicability and reliability concerning viticultural aspects and primarily aims at evaluating measures of adaptation rather than predictions. The results demonstrate the extent and effects of climate change on the viticulutural areas in Europe. Possible impact on grapevine phenology and wine quality for the Rheingau and pest risks for Sardinia is given as an example.