CABI Blog

At the moment, the idea of wines from Scandinavia, or other northern climes, may seem fanciful. But by the end of this century, climatologists suggest that Sweden could be producing Riesling or Chianti, Germany will be better known for luscious red wines than the current whites, and California’s famous Napa Valley could be as hot as the Central Valley’s Lodi appellation is now. So those of us who buy wine based on its origin, with certain expectations of what it will taste like, will have some keeping up to do.

In a world of changing climate, there will be big winners and losers in the wine growing world. In some European regions which have sometimes struggled to ripen grapes, global warming is currently producing classic vintages most years. German wines are said to be improving (see abstract by Storchmann at the end of this article), English wines are rapidly getting a better reputation, and in Bordeaux growers can now consistently ripen their grapes.

But wines from warmer regions have less cause to be thankful for rising temperatures. A study from Florence University published in wine magazine VQ assesses what will happen to some of Italy’s most famous wines if the climate changes as predicted in the next 30-40 years. The research shows that while warmer temperatures may favour wine quality, predicted intense rain will be bad news. And in some areas such as Tuscany, high temperatures, and rain concentrated into fewer events, will cause grapes to over-ripen and threaten the quality of wine.

A news release from CSIRO last year said that in Australia, there would also be winners and losers. Modelling projected temperature increases by 2030, research suggested that grape quality could be reduced by 12-57% compared with current conditions, if adaptive measures are not implemented.

The environmental sensitivity of wine grapes makes them a good indicator for the effects of climate change on agriculture. Research also highlights how the industry may have to make big changes to adapt. Grape varieties may become unsuitable for areas where they are currently grown, but become able to be planted in new regions. The industry may need to breed new grape varieties to suit warmer climates, or which require less water. Nevertheless, scientists like Gregory Jones from Southern Oregon University fear that in the USA, most of the best terrain for premium grapes could be lost by the end of the century.

If new areas for wine growing come into play as old ones become unsuitable, then the main effect on us as wine drinkers may simply be that we have to get used to the idea of drinking a wine from southern Sweden rather than Italy. But the economic consequences for vineyard owners in vulnerable areas may be much bleaker.

CAB Abstracts has coverage of all the academic literature on the possible effects of climate change on agriculture and horticulture. A few sample abstracts from CAB Direct are given below to give a taster of the research.

Extreme heat reduces and shifts United States premium wine production in the 21st century.

White, M. A. ;  Diffenbaugh, N. S. ;  Jones, G. V. ;  Pal, J. S. ;  Giorgi, F. ;   
 
Proceedings of the National Academy of Sciences of the United States of America  , 2006  , 103  , 30  , 11217-11222  , 50 ref.   
 
Premium wine production is limited to regions climatically conducive to growing grapes with balanced composition and varietal typicity. Three central climatic conditions are required: (i) adequate heat accumulation; (ii) low risk of severe frost damage; and (iii) the absence of extreme heat. Although wine production is possible in an extensive climatic range, the highest-quality wines require a delicate balance among these three conditions. Although historical and projected average temperature changes are known to influence global wine quality, the potential future response of wine-producing regions to spatially heterogeneous changes in extreme events is largely unknown. Here, by using a high-resolution regional climate model forced by the Intergovernmental Panel on Climate Change Special Report on Emission Scenarios A2 greenhouse gas emission scenario, we estimate that potential premium winegrape production area in the conterminous United States could decline by up to 81% by the late 21st century. While increases in heat accumulation will shift wine production to warmer climate varieties and/or lower-quality wines, and frost constraints will be reduced, increases in the frequency of extreme hot days (>35 deg C) in the growing season are projected to eliminate winegrape production in many areas of the United States. Furthermore, grape and wine production will likely be restricted to a narrow West Coast region and the Northwest and Northeast, areas currently facing challenges related to excess moisture. Our results not only imply large changes for the premium wine industry, but also highlight the importance of incorporating fine-scale processes and extreme events in climate-change impact studies.

English weather and Rhine wine quality: an ordered probit model.
 
Storchmann, K. ;   
 
Journal of Wine Research  , 2005  , 16  , 2  , 105-119  , 33 ref.   
 
This paper analyses the quality of Rhine wine vintages from Schloss Johannisberg over the last 300 years. It draws on vintage lists and transforms the verbal qualitative assessments into five quality ranks. These ranks are related to temperature and precipitation data, using an ordered probit model. Since reliable instrumental weather data for the Rhine region do not exist for the time before 1826, we utilized the English Manley temperature series (beginning in 1659) and precipitation data for Kew Gardens (available from 1697 on). In addition, we used index data for Germany from the historical climate data bank Historische Klimadatenbank Deutschland of the University of Heidelberg. The results show that English weather is a good proxy variable for the actual weather conditions in the Johannisberg vineyards. While Frankfurt weather data yielded a better goodness-to-fit, the data covered only half of the observation period. The models show that the biggest marginal temperature effects occur in the months May and September, i.e. during the blossoming and ripening periods. A 1 deg C temperature increase for the entire growing season will increase the probability of harvesting a top vintage from approx equal to 20% to >50%. Therefore, the model suggests that moderate global warming is likely to improve the quality of Rhine wines.

Global warming’s impact on wine.
 
Tate, A. B. ;   
 
Journal of Wine Research  , 2001  , 12  , 2  , 95-109  , many ref.   
 
The dramatic melting of the Arctic ice cap over the last decade may be a harbinger of significant warming in the Northern hemisphere in the next few decades. The consequence of such warming will be the ability of Vitis vinifera to thrive in more poleward locations than it does today, with the corollary that some areas now ideal for a given cultivar will cease to be so. In addition, pests and infections currently limited by winter cold will expand their ranges poleward. Changes in dominant climate patterns will also occur, but as temperate changes will be ongoing (in particular a shrinking differential between the poles and the Equator), shifts in rainfall patterns will also change continuously. The rise in sea level expected to accompany warming will have a direct impact on the mesoclimates of vineyards near coasts, as well as flooding some prime vineyards. Accompanying global warming has been a significant rise in the atmospheric carbon dioxide concentration, which is changing the texture of oak used for wine barrels and may be changing the components or their proportions in ripe grapes.