It seems clear that the tragedy on Marmolada caused by the detachment of a saracus, after recurring heat waves, including the one of the previous few days, should make us think about climate change. Unfortunately, we will be forced to get used to these extreme events. Of the last 20 years, 19 have been the hottest, with 2020 seemingly holding the dismal record in Europe. Despite a legion of deniers, most of the available scientific evidence shows that this anomaly is due to increased greenhouse gas (GHG) emissions from human activities. The current average global temperature is about 1 degree higher than pre-industrial levels in the late 19th century. That sounds like nothing, but scientists warn us that it is a lot. Indeed they believe that a two-degree Celsius increase over pre-industrial levels could have catastrophic consequences for both climate and the environment.
But what are the consequences that these extreme events caused by global warming bring to the world of wine? A world that has been tackling the issue vigorously for years now (in the world of wine and agriculture in general, there are very few deniers). Let us at least try to raise the level of attention and urgency on an issue that affects us all without speculating.
In Italy and other areas dedicated to the cultivation of vines, the effects of global warming are evident and are being felt in the form of an increase in extreme phenomena such as cloudbursts (so-called water bombs), high winds, abnormal gradations, late frosts, heat waves and prolonged periods of drought. Within the agricultural sector, viticulture is likely to be one of the most sensitive sectors. Indeed, rising temperatures and lack of rainfall have serious repercussions on vine productivity and the health and quality of harvested grapes.
Among the most apparent indicators are early harvests and, on a large scale, the migration to higher altitudes and northward of vineyards, in places where until a few years ago, it would have been unthinkable to find them. According to research carried out by the French National Institute of Agronomic Research (Inra), if, as is now predicted, average temperatures rise by 2 degrees Celsius by 2050, 56 percent of the world’s current wine-growing regions could disappear.
If then, by 2100 the increase reaches 4 degrees, this loss would reach 85 percent. The Mediterranean area would suffer most, with Italy and Spain losing 68% and 65% of climatically suitable areas under a +2°C warming scenario, with gains of only 9% and 5%, respectively, for crops shifted to cooler areas. This situation would also affect olive growing in the southern Mediterranean, the tomato industry, and even fisheries, as the Mediterranean is already experiencing tropicalization and the emergence of exotic fish.
The situation is alarming, and farmers are implementing a large number of strategies to counter the phenomenon. An increase in average temperatures during the growing season of the vine leads to an acceleration of the sugar ripening of grapes, which unfortunately is not followed by phenological and aromatic maturity. Too hot summers result in grapes rich in sugar but poor in acid, aromatic and phenolic compounds, which are then the ones that allow us to produce the wines we like best.
Italian wines have increased their level of quality, thanks in part to the ability of winemakers to adapt to climate change. Rising temperatures have also brought with them an increase in disease. I am not among those who predict that great Champagnes will soon be made in southern England, Barolos in the Alps, and that one will have to go to Sweden or Canada to drink a good Sangiovese.
For established vineyards, there are remedies that, at least in the short term, can give good results. One can reduce the practice of leaf stripping (stripping is used to expose the clusters to the sun better), thus allowing the berries to remain shielded from the leaves and reducing the temperature of the clusters. Another practice is to delay pruning to delay budding. You can also use
Kaolin, a white clay that is also allowed in organic crops, which is dissolved in water and then sprinkled on the plants and, due to its white coloration, can reflect the sun’s rays while limiting their absorption.
Grassing the space between the rows is also a good tool for lowering temperatures at the cluster level. One can even use filtering nets, already available in different colors depending on the degree of shading, which are placed at the cluster level to reduce direct irradiation, not to mention the possibility granted by many DOC and DOCG specifications of rescue irrigation in case of prolonged drought. These are just a few possible remedies.
For new vines, in addition to the possible upward shift of the crops, more water stress-resistant rootstocks can be studied, and where possible, select vineyard orientations other than the traditional south or southeast, also act on the orientation of the rows and prefer those soils capable of making water available for the crop during the growing season. The last frontier-described in the study-is then that of genetic research, to which several countries including Italy contribute, focusing on the creation of new varieties of hybrid vines obtained from crosses between European vitis vinifera and different species of non-European vines. They are characterized by a greater ability to resist disease, withstand high temperatures, or develop higher acidity.
I have tasted some wines made from these experimental vines with names that sound similar to the traditional ones, such as the whites Souvigner Gris, Sauvignon Kretos, Sauvignon Rytos, Soreli, Kersus, and Johanniter, and among the reds Cabernet Cortis, Cabernet Volos, Volturnis and Merlot Khorus and I must admit that the results are satisfactory.
