A new study published in the Proceedings of the National Academy of Sciences shows that around 85% of wine regions are at risk from climate change. Its conclusion is that wine makers must diversify varieties of grapes used.
Climate change is indisputably ushering in a new age of unfavourable and difficult weather conditions for winemaking regions. And the most beloved vineyards in the world must now choose between diversifying their offerings or only being able to harvest dwindling crops. This is the message from a new report authored by the Nasa Goddard Institute for Space Studies and Colombia University.
Climate change will lead to wine shortage
The report says that even if the world’s governments adhere to the Paris agreement, which limits greenhouse gas emissions to causing global warming of 2C, the impact on wine as we know it would be huge. Assuming that the Paris agreement is honoured, and the world warms by only 2C, wine growing regions could shrink by 56%.
And that’s the best-case scenario. At present, the world is not on target to comply with the Paris agreement, which was signed in 2015. In 2019, greenhouse gas emissions were 4% more than when the treaty was signed. The United Nations says that current emissions trends mean the world will endure a temperature increase of 3.4C by the end of the century.
The report says that should the globe warm by 4C, then 85% of vineyard viable land would not be able to produce quality wine. This is because wine grapes are hugely sensitive to the changes in temperature and seasonality that climate change is causing.
Unavoidable loss of viable vineyards
Whether the 2C limit is maintained, or the worst case 4C warming is hit, there will be unavoidable losses in land suitable for vineyards. The team behind the report says that this is because of the shifting temperatures which would affect the grapes during their ripening period.
However, the team also says that diversification of grape varieties should be able to reduce losses in a significant way. At a global warming level of 2C and no further attempts to change this, more than half of the current wine-growing regions in the world would no longer be suitable.
But, if wine producers change to grape varieties that can withstand more temperature changes, then just less than a quarter of viable vineyards will be lost. For example, the team suggests that in Burgundy wine growers should replace current grapes such as Pinot Noir with Grenache or Mourvedre as they can withstand higher temperatures. Similarly, in Bordeaux, Merlot and Cabernet Sauvignon could be replace with the heat loving Mourvedre grape.
Challenges for traditional wine growing regions
The study recognises that these kinds of changes would be difficult in regions steeped in history. It would also affect the legalities surrounding which grapes have to be used in specific regions to qualify as certain wines.
However, change is already happening in some regions. In Bordeaux, for example, Cabernet Sauvignon is the dominant grape. Only a few others have been legal to use, including Petit Verdot, Malbec, Merlot and Cabernet Franc. However, in July 2019 this changed when Bordeaux wineries authorised four new red grapes. These were specifically endorsed to tackle rising temperatures in the region and are Arinarnoa, Castets, Touriga Nacional and Marselan.
Further discussions are ongoing throughout Europe regarding new laws to make it easier for traditional wine regions to diversify the grapes they grow. Not only will this mean an enormous culture change for regions that have been growing the same varieties for centuries, but also from consumers who must accept that their favourite wines may change.
Diversification is the way forward for winemakers
The study says that certain cooler regions in New Zealand, the US Pacific Northwest and in Germany could be mostly unscathed under the 2C warming scenario. These regions might become more suitable for varieties including Grenache and Merlot, while grapes that need cooler temperatures could move into brand new wine growing regions further north.
Regions that are currently very hot, such as in Spain, Italy and Australia will face the biggest loss of vineyard land, according to the scientist behind the report. This is because they’re already limited to planting only grapes that can grow in the hottest temperatures.
Under the 4C global warming scenario, diversification and grape swapping will be less affective. The report shows that planting only climate-specific grapes in rapidly heating areas will reduce losses by about a third (from 85% to 58%).
Ultimately, the study concludes that there is much to be done to protect the world’s wine growing regions. And how well any chosen strategy will work will depend upon the winegrowers being able to adapt locally.