Wine in the Time of Global Warming

An image of a grape vine trellised to a date palm provides a whimsical view of what the future might hold for viticulture in the next fifty years. However, the article that accompanies this illustration makes it clear that the impact of global warming is no laughing matter (Goldfarb 2006). Moreover, despite former U.S. Vice President Al Gore’s reference to global warming as an “inconvenient truth,” according to scientists throughout the world, the truth can no longer be ignored and it most definitely will hurt us.

The earth is indeed getting warmer and the issue of global warming, or, more correctly, climate change, has been brought to the forefront of the public’s attention. Numerous governmental agencies and researchers have published reports on the crisis, making the message difficult to disregard. The scientific projections are dire and threaten to negatively impact the planet as we know it. The wine industry is not immune and several serious consequences are predicted for the wine regions of the world, as climate change jeopardizes their ability to grow quality fruit.

Climate Change Research & Projections
As they say, there is nothing new under the sun. In this case, it might be interpreted quite literally. Historically, climate change isn’t novel; the Earth’s climate has changed dramatically before as evidenced by reports of thriving English vineyards back in the 1200s (Weise 2006). The difference is that the change is no longer a natural phenomenon. Rather, today’s change in average temperature is primarily linked to human activities, which have resulted in an increase in atmospheric concentrations of greenhouse gases, notably CO2 (IPCC 2001). More specifically, since 1970, carbon emissions have risen 30% over pre-industrial revolution levels, due to the combustion of fossil fuels, along with changes in land use and the release of aerosols into the environment (Pew 2004). Generally, scientists have found that average temperature increased 1oF over the past 100 years (IPCC 2001).

Looking ahead, the Intergovernmental Panel on Climate Change (IPCC)’s most recent projections predict a shift between 2oC and 4.5oC, with an average global daily temperature rise of 3oC by 2100 (Warren 2006). These newer predictions are more precise than their previous forecast of 1.4 oC - 5.8oC, but are still substantial (IPCC). Data from Jones show the Bordeaux and Napa Valley regions each increasing by 1.2oC and Portugal increasing as much as 2oC over the next 50 years (2005a). Expectations include hotter summers for Europe and North Africa, along with altered patterns of rainfall (Gilby 2006).

Scientists advise that if greenhouse gas levels are stabilized to 400 parts per million, some of the temperature increase can be avoided (Warren 2006). In fact, the IPCC forecast notes that the rise could be held to 2oC, if greenhouse gases remained at current levels (ibid). However, studies have found that proposed efforts to reduce in greenhouse gases would likely result in a fall in real wages (ibid). Yet, even remaining at current emissions will have an impact. Field, specifically measured the effect of climate change on California and looked at both best (current level emissions) and worst (quadrupled emissions) scenarios (Fox 2004). Even in the best case, Field expected a fourfold increase in the frequency of heat waves and extreme heat in places such as Los Angeles, with mortality figures increased double to triple the number seen today (ibid).

Impact on the Wine Industry
While these temperature changes seem small, their affect on the viticultural industry will be significant. Grapes are particularly sensitive to heat and need to stay within a narrow temperature band to produce quality fruit. Thus, as explained by Bernard Seguin, “‘One degree increase in temperature is very important’” (Voss 2006). Moreover, Jones contends that, “…climate arguably exerts the most profound effect on the ability of a region or site to produce quality grapes and, therefore, wine” (2005a).  Consequently, discussions of impact have centered on quality as “…even tiny changes can be the difference between a $200 Cabernet Sauvignon and cooking sherry” (Weise 2006).

According to Jones’ study, all regions are experiencing growing season warming (2005b). For some regions, the initial changes have been helpful. Cooler climates, such as the Mosel and Rhine regions, have benefited from the increased temperature, with vintages improving with warmer weather (Just-drinks 2003). In concert, Ashfelter and Storchmann expect the value of Mosel Valley vineyards to increase 20-50% over the next several decades as the temperature rises 1-3oC (Holzer 2006). Excellent vintages in Bordeaux and Champagne have been other indicators of this positive outcome (Weise 2006).

Conversely, warmer climates have suffered from the additional heat, which has been especially true for areas currently at the high end of the spectrum for growing conditions such as La Mancha; Central Valley, CA; and southern France (Buckley 2006). Many wines from these warmer areas have shown an imbalance in alcohol and acidity (Just-drinks 2003). There is also concern regarding changes in flavor profile, along with imbalances in tannins, sugars and aromas, which will ultimately impact style and wine quality (Gilby 2006).

Richard Smart expects a loss of color in red wines and of varietal flavor (Buckley 2006). Similarly, Hans Schultz has predicted an impact on flavor development, due to the combination of increased solar radiation and temperature (2000). Already, in the Napa Valley, the average alcohol level has increased from 12.5% in the 1970s to 14.8% in 2001 (Rademakers 2006). Also, a reduction in the ageing potential for wines made from these stressed vines is likely, further impacting quality (Gilby 2006). Equally important, CO2 increases might alter the texture of oak wood, thus changing the character of wines aged in barrel (Jones 2005b).

Consequently, White warn that the grape growing industries in Napa, Sonoma and Santa Barbara may not exist in the future, predicting that as much as 81% of California acreage will be rendered unsuitable for premium grape growing as climate change continues (2006). Overall, White suggests that as the area of production contracts and shifts, a change to higher yields of low quality will ultimately produce lower-quality and lower-priced wines, with the highest-quality, highest-priced wines declining greater than 50% (ibid). Furthermore, declines in these premium regions may also negatively impact local culture and tourism (Teague 2006).

Another growing problem is drought, which reduced the 2005 harvest for the Torres wine company in Spain (Kakaviatos 2006). Predictably, there is anxiety regarding the availability of water (Voss 2006). With temperatures increasing more in the coldest areas than in warmer ones, stress on the polar ice caps is calculated to reduce the Sierra snow pack by 30-70%, which could “fundamentally disrupt California’s water rights system” (Fox 2004). In Australia, there is concern that the mainland would receive lower rainfall (Warren 2006). Not surprisingly, it has been suggested that water may be the next “investment frontier” (Voss 2006).

The resultant warmer winters and early arrival of spring can also be problematic, especially if a hard frost follows early spring budding (Voss 2006). Further, there is a real danger of vine infestation, particularly from Glassy Winged Sharpshooters, which spread Pierce’s Disease, and the pest hyalestes obsoletus, which is responsible for Bois Noir (Furer 2006). These vine diseases already pose a threat, but with milder winters, insects are living longer and migrating farther distances, thus, increasing both the perimeter of affected areas and the population of insects available to perpetuate disease (Buckley 2006).

Response of the Wine Industry
Given the evidence, climate change clearly must be addressed. Individual growers can and have modified their viticultural practices to adapt to the changing conditions. In Spain, Miguel Torres has begun using irrigation, which wasn’t done ten years ago (Kakaviatos 2006). Similarly, a Napa Valley grower admitted that irrigation was now a common part of his daily practice (Goldfarb 2006). However, in addition to the expense of such systems, the ability to irrigate may be curtailed by the rise of salinity in freshwater (Furer 2006).

Other viticultural proposals have included a switch in trellis systems to those that shelter the grapes from the intense heat, as well as using date palms to provide additional shade (Goldfarb 2006). Likely, vinification practices may change as well, with a need for more frequent acidification and less use of malolactic fermentation. As Europe continues to get warmer, it will have to reconsider “tradition-bound rules against irrigation” and other appellation laws to permit changes in practice. (Rademakers 2006).

The switch to different grape varieties, especially those better suited to warm weather, has also been proposed (Goldfarb 2006). Ashenfelter and Storchmann further recognize the need to breed more heat-resistant grapes, which has not yet been undertaken (Holzer 2006). Likewise, speakers at the World Conference on Global Warming proffered two solutions: to invest in grapevine breeding programs and in improved irrigation systems (Buckley 2006).

Unable to stand the heat in hotter regions, some producers are getting out, making the decision to buy land elsewhere. Specifically, Miguel Torres has begun to head north in search of land in cooler regions (Kakaviatos 2006). It would seem he is not alone. As Richard Smart suggests, “For wineries, it will boil down to real estate issues…The smart ones will move quickly and buy cheap” (Voss 2006). Among areas to explore, it is expected that places such as Maine and Northern Europe, which were previously too cold to successfully ripen grapes, will emerge (Walker 2006). In Southern England, the total acreage of vineyards has increased considerably and areas for quality Australian Cabernet Sauvignon have been moving south (Rademakers 2006).

Facing the future, vineyard owners will need to examine key decisions and their financial consequences. Costs associated with replanting new varieties will be significant; but buying new land and replanting will be even greater. Moreover, individual growers may have less capital available to make such purchases and take on risks and could be reluctant to uproot themselves and their families. But, those who wait may find changes in land value to their detriment. Reinterpreting Ashfelter and Storchmann’s vineyard valuations, it is likely that the value of premium vineyards will depreciate if they can no longer produce quality fruit. Thus, some may find that they can’t sell their land at the high price they paid for it. Finally, research programs on irrigation methods and breeding heat-resistant grapes must be undertaken, but funding for these programs is more liable to come from large corporations and institutions since individual growers can’t afford these efforts on their own. Overall, multinational drinks companies would seem to be in a better position than individuals to make the major changes required such as divesting of existing properties and investing in new land, new technology and new plantings.

Conclusion & Personal Commentary
Research clearly indicates trouble ahead for all of Earth’s inhabitants, with far-reaching repercussions that will impact life on the planet. Agriculturally-based business, including the wine industry, will be forced to respond. Unfortunately, solutions such as replanting, land purchase and viticultural research, are quite costly and may drive smaller producers out of business. Reducing the industry to multinational drinks companies may impact diversity and regional style, which are already at risk due to climate change.

There are also important implications for terroir. The expression of terroir has been linked to Europe’s stress and relief cycles as opposed to the irrigated New World (Gilby 2006). Accordingly, if there are no relief cycles, irrigation use expands or both, this expression may no longer exist. Furthermore, as growers seek to move to cooler areas, the temperatures may be more hospitable, but other climatic elements and soil types may ultimately affect the quality of the wine. Moreover, while adaptation comes more easily for New World wine regions, it may be harder for Old World regions to respond appropriately with changes to their viticultural laws.

Finally, it is imperative that climate change be viewed through a wider lens. Manipulating vines or grape varieties to adapt to the changes ignores the larger problem. Solutions that seek to reduce emissions, and thus mitigate those affects, should be considered, despite their immediate economic impact.


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