Bob Ward looks at climate change and the future of Dorset winemaking
Dorset’s winegrowers have been benefiting from the rising impacts of climate change, but must be prepared to adapt to hotter temperatures if they want to continue to produce award-winning vintages.
The county is home to 30 of England’s 1016 vineyards and wineries, according to the national database compiled by wine expert Stephen Skelton.
Even though it is dwarfed by the output from the south-east counties, particularly Kent and Sussex, Dorset is home to some champion wines.
At the International Wine and Spirit Competition earlier this year, Langham Wine Estate won a gold medal for its Blanc de Blancs, made from Chardonnay grapes, as did Bride Valley for its Reserve Brut 2018, produced from Chardonnay and Pinot Noir varieties.
These winners follow a long line of decorated sparkling wines, using grape varieties that are benefiting from temperatures that have warmed by about 1 Celsius degree during the growing season between April and October.
One previous study showed the importance of climate during an assessment of each of the components of terroir, the term coined by French winemakers to encompass the factors controlling wine quality.
It found that climate accounts for over 50 per cent of the variation in quality. Soil type is responsible for 25 per cent of the variation, and grape variety controls about 10%. The cultural component of wine contributes 15 to 20 per cent of quality.
Dorset and other parts of southern England have chalky well-drained soils, and average temperatures of between 13 and 15 degrees Celsius during the growing season.
This is the same combination of geology and climate that has allowed the Champagne region to cultivate Chardonnay, Pinot Noir and Pinot Meunier grapes for the world’s most famous sparkling wine variety.
However, rising temperatures in Champagne mean that its grapes now ripen more quickly and become sweeter, losing the distinctive acidity that is an essential component of its sparkling wines.
But warming has provided the ideal climate in Dorset and other parts of southern England to grow Champagne’s famous grape varieties.
The main grape varieties grown in England during the 1990s, were Müller-Thurgau, Seyval Blanc and Reichensteiner, but from the mid-2000s Chardonnay and Pinot Noir started to dominate as English growers focused increasingly on sparkling wine production.
The latest figures show that 2023 was a record-breaking year for British wine, with the production of nearly 162 million litres of wine, more than three-quarters of which was sparkling.
According to the trade association, Wine GB, the dominant varieties grown in Britain in 2023 were Pinot Noir, Chardonnay and Pinot Meunier, respectively representing 27, 32 and 9 per cent of the total planted area.
The overall area occupied by vineyards has more than doubled over the past 10 years.
The warmer months have extended the growing season, allowing the dominant grape varieties to achieve the right level of maturity before harvest in October.
Since the 1990s, flowering in UK vineyards has typically occurred in mid to late June, compared with the period between 1970–1990, when flowering in most years occurred in early July.
The additional warmth means that frosts, which can cause severe damage to vines during the growing season, are much less common in April.
However, warmer temperatures mean that vines start growing earlier, and can be exposed to frosts in March.
A recent study of climate resilience in the UK wine sector (CREWS-UK), funded by the Natural Environment Research Council, warned that continued climate change will create new challenges and opportunities for growers in Dorset and across the country.
It revealed that the spring months of April and May have experienced large increases in average temperature over the past few decades. These are the months when budburst and initial shoot growth occur.
The study revealed that the highest yielding years for the English wine industry, including 1996, 2006, 2010 and 2018, were primarily due to perfect temperature and weather conditions during flowering and ‘fruitset’, when the grapes first appear on vines.
By contrast, low yields occurred in years such as 1997, 2007, 2008 and 2012 due to wet and cold weather during flowering and fruitset. Heavy rainfall during flowering in June can be particularly damaging for yields.
Heavy rain before harvest in October can also be destructive by encouraging the growth of diseases.
While analysis by the Met Office suggests climate change is creating warmer wetter winters and drier summers, the warmer atmosphere can retain more moisture, increasing the probability of downpours when it rains.
The increasing risk of acute rainfall events during the growing season poses a mounting problem for Dorset’s wine industry to manage.
However, rising temperatures are also likely to create similar difficulties to those currently experienced by the Champagne region.
This means that Dorset winemakers should turn to other warmer regions, such as Burgundy, to provide insights into the future.
Although Pinot Noir grapes are an essential component of Champagne’s distinctive sparkling wine, in a warmer climate they can ripen sufficiently to provide the basis for high-quality still red wines.
The CREWS-UK study found that warming over the next 20 years will mean the average temperature during the growing season across parts of southern England, including Dorset, could reach 15 degrees Celsius.
This temperature represents the climate-maturity threshold for a wider selection of commercially popular grape varieties, many of which are rarely grown in Britain at present, including Pinot Gris, Gewürztraminer, Riesling, Chardonnay, Sauvignon Blanc, Semillon, Cabernet Franc, as well as Pinot Noir.
Hence, if the British wine industry wants to continue to grow in a changing climate, it will need to expand its range of wines and cultivate grape varieties other than those that have been producing award-winning sparkling wines.
Unfortunately the climate is likely to continue to change beyond 2040, creating great uncertainty about the future of British winemaking beyond the next 20 years.
But in the meantime, there are signs that Dorset winegrowers are already rising to the challenge of keeping pace with the changing climate. Langham Estate was awarded a silver medal for its 2019 Pinot Noir in this year’s International Wine and Spirit Competition.
It may not be long before other varieties are as celebrated as Dorset’s sparkling wines.
Bob Ward FGS FRGS FEI is Policy and Communications Director at the Grantham Research Institute on Climate Change and the Environment
