Global warming and its impact on wine

In 1989 Richard Smart‘s suggestion that Bordeaux might one day be better suited to Grenache than Cabernet was met with derision. Now, as the dangers of global warming are brought into stark relief, he considers the viticultural changes being produced today.

The first week of December 2015 saw the start of the Paris Climate Conference, hailed by some as the world’s last chance to save the planet from man- made atmospheric pollution from carbon dioxide (CO2) and other gases. The predictions around climate change, including global warming, are dire, from rising sea levels to starvation, maybe leading to wars.

Among such possible social unrest, it almost seems trite to be concerned about the wine which future consumers might enjoy in 2050, or even 2100. However, many grape growers and wine producers are already noticing the early effects of warming and are planning adaptation strategies. Miguel Torres of Spain is investing in higher altitude, cooler vineyards, and Brown Brothers of Australia has invested in the southernmost state, Tasmania. I was one of the first viticulturists to bring climate change impacts on wine to wider notice, using the phrase “Wine will be the canary in the coalmine for the world’s agriculture”.

I remember the responses of a sceptical audience at the Luxembourg OIV (International Office of Wine) General Assembly of 1989, when I delivered a paper on global warming implications for wine appellations. Among other ideas, I suggested that in the future the variety Grenache might be better suited to Bordeaux vineyards than Cabernet Sauvignon – a suggestion greeted by hoots of derision from the audience. Time will tell on this one and on related issues. This was probably the first time that climate change was discussed at OIV. Now, 26 years later, it features in a major way on the agenda and action plan – as it should.

The style and quality of a wine are much affected by weather, especially by temperature and rainfall. ‘Climate’ is the average of weather conditions over time; it is the weather we might expect. The world of wine, especially the Old World,has developed regional specialities of grape varieties and wine styles, and many of these have become benchmarks for the rest of the world. These regions are demarcated much more by temperature than rainfall.

VARIETY AND CLIMATE
It is this important interaction between grape variety and climate, especially temperature, that makes the grape and wine sector so different from other forms of agriculture. The world of wine is generally classified into discrete regions, as defined by the French appellation schemes. Each region has a discrete mix of varieties and possesses distinctive physical features – climate, geology, soils – which produce distinctive wine styles. Of these physical attributes, climate, and more specifically temperature, is known to be the most important in differentiating between regions and wine styles. I selected some regions producing renowned and distinctive wine styles to make the climate comparisons listed in the table.

Regions from France and the rest of the world are arranged from cooler to hotter, along with a listing of two important varieties per region. Most of the data is taken from The World Atlas of Wine by Hugh Johnson and Jancis Robinson (2013, seventh edition). That book, sadly, does not include the important but hot (generally) bulk wine areas which I have added for Australia (Sunraysia) and the US (Fresno, California).

As a heat measure I have used the average growing season temperature, as in the World Atlas. I show the present average temperature, and how this might be influenced by an increase of 1.5°C and 2.5°C.The table illustrates several points.

The range of temperatures for the French regions is 5.1°C. The temperature difference from the UK, one of the coolest wine regions in the world, at 14.1°C, to one of the hottest, Fresno in California’s Central Valley (23°C), is 8.9°C.

In the overall scheme of things, these are both small ranges of temperature. The average temperature difference from one region to the next warmer region is very small, at 0.63°C. Compare these figures with the projections based on global warming for this century, ranging from2°C to more than 4°C. Even the smallest temperature increase projected for this century will see massive changes within and between the present wine regions.

One of the most basic assumptions underlying appellation systems is that the region for which the appellation exists has an optimal mix of varieties corresponding with conditions in the region, especially climate, and, more specifically, temperature. When the temperature increases, this ideal combination of variety and regional temperature will change and, if all else in the equation remains the same, there isa high probability that wines will lose their reputation.

As an example, an increase of 1.6°C will make Bordeaux like the present Languedoc, where Grenache and Carignan are important varieties; an increase of 2.0°C will make Bordeaux like the southern Rhône, where Grenache and Syrah are now important. Grenache plantings in Bordeaux may not be all that unlikely this century.

A TIME OF CHANGE
So, how will we adapt? What will we change – the region or the variety? My guess is that it is far more likely for present regions to change varieties than to move all their vineyards, wineries and infrastructure to new regions. I can imagine, however, that many distinguished regions will struggle to hold on to their prestige and the regional reputation associated with their present varieties. Bordeaux may now claim to produce better quality Cabernet Sauvignon than the Languedoc or Southern Rhône, but in future it may be difficult to argue that the new style, like those of the present Languedoc or Southern Rhône, remains the world’s best Cabernet Sauvignon.

‘I would like to see the OIV support a multi-country effort to breed new varieties adapted to warmer temperatures. I believe it is eminently achievable and eminently desirable, and can be done in time’

So the world’s wine map will slowly change – and not without considerable resistance from many quarters. It should be noted, however, that there will be fewer changes in some New World countries, like Australia, where over the last several decades, under the strong marketing influence of ‘varietal’ labelling, similar varieties are planted everywhere, in all regions, whether cool or hot. This applies very much to Cabernet Sauvignon and Merlot, but also to Chardonnay and even, to some extent, Pinot Noir.

WINNERS AND LOSERS
In the global warming scenario, there are many variables and possibilities. For sure, present cool wine regions will be ‘winners’, and new wine regions will develop in poleward directions and at higher altitudes. Present hot regions, which include some of the world’s largest wine regions, will be the big ‘losers’. There will be less impact on wine quality in the southern hemisphere than the northern hemisphere because of the effect of its greater ocean area and the influence of the world’s biggest iceblock, Antarctica. Chile, Argentina and Tasmania will suffer least impact. Mediterranean Europe, especially Iberia, will suffer the most.

I would like to see the OIV support a multi-country effort to breed new varieties adapted to warmer temperatures. I believe it is eminently achievable and eminently desirable, and can be done in time. What might the concerned wine consumer do to help avoid climate change?

If you are living in some affluence in the Western world, you and your lifestyle are considered by many to be the primary perpetrators in treating the earth’s atmosphere as an infinite-capacity sewer. As one scientific paper explains: “The severity of climate change impacts is dependent on the extent to which individuals choose to engage in mitigation behaviour. Also, many governments’ actions shall reflect the will of their people, and so individual attitudes to climate change are important.”

TAKING THE INITIATIVE
Let me conclude with an example of a wine scientist taking personal initiative to help improve public awareness of the climate change problem. Gary Pickering is a native New Zealander now working as a professor of biological sciences and psychology at Brock University, Ontario, Canada, and is a member of a Sustainability Research Centre. Ontario has only 17,000 hectares of vineyard, on the Niagara Peninsula.

Gary and his colleagues have published scholarly papers about the implications of global warming for the local wine sector, including expansion to the north into unplanted areas. Especially intriguing to me was his paper entitled ‘Head in the (Oil) Sand? Climate Change Scepticism in Canada’. Despite Canada’s actions as a modern leader in world affairs at manylevels, its record in climate change mitigation is woeful, putting it bottom of the G8 and 30 OECD countries – the worst performance of any industrialised nation.

‘There is evidence already of changes in grape and wine production from the last two decades; the next four decades of this century will bring many more’

Professor Pickering has investigated why this is so, conducting a survey of public opinion about climate change. Western Canada is the location of the oil sand industry, the country’s largest CO2 emitting sector, which contributes heavily to the regional economy. In a nutshell, the survey indicated that the most sceptical respondents were male, lived in Western Canada and agreed with Conservative politics – so their scepticism appears ideological rather than being evidence-based. This has been found to be the case in other Western countries. For countries with democratic governments, public opinion is important, and it is useful to understand how it might be influenced to promote climate change mitigation, at both the personal and societal level. The wine world will change, although less quickly than the climate, owing to human resistance to change. There is evidence already of changes in grape and wine production from the last two decades; the next four decades of this century will bring many more. So raise your glasses in a toast to the unknown future of wine, reminding yourself, with a slogan borrowed from peace movement, to ‘think internationally, act locally’.