

Tom Filmer examines likely future effects of climate change for viticulture and what mitigation strategies can be put in place.


The last four years have been the planet's hottest on record and increased warming is expected going forward.


Increased soil salinity may also occur as a result of rising sea levels. Increased incidence of pests and disease, such as powdery mildew, can also result from warmer average temperatures.


Water stress can reduce grape yield and negatively affect fruit composition.


Wine's taste and characteristics are affected by weather variations which can alter grapes' sugar, acid and tannin content, causing variation from vintage to vintage.

Higher temperatures activate advanced grape phenology, moving ripening to warmer summer periods, reducing aroma compounds.



New Zealand's favourite, sauvignon blanc, which makes up 85 per cent of our export sales, may risk losing its distinctive flavour with increased temperatures liable to promote a flavour profile which is more mellow tropical fruit than its current beloved acidic gooseberry.

Pinots grown in cool climate areas now may similarly suffer. Strategies to adapt to climate change are required in order to preserve wines' original style typicity.





Increased temperatures will mean soil management practices will come to the fore to better manage grapevines' water supply, control vigour and avoid soil erosion, as a European Winegrowers' Guidance Manual advises.


The manual further advises that to minimise soil erosion and to maximise nutrient and water storage, mulching with plant fibres, is highly recommended.

This practice also increases organic matter under the vine, limits the use of herbicides and reduces soil evapotranspiration to avoid severe water stresses to the grapevine during episodes of drought.


To offset the increase in pests and diseases that climate change may bring, consider implementing integrated pest management, an ecosystem-based management practice that integrates biological, cultural, physical and chemical tools to manage pests and diseases in the vineyard.


Internationally, some winegrowers, dramatically, are relocating to cooler, higher altitude areas, planting heat-resistant varieties and increasing canopy coverage to provide shade.

One Californian grower has embarked on a project to breed a new grape variety that is capable of being dry farmed (without irrigation) and will withstand increased heat.

Research, such as the European manual referenced above, also indicates planting on south-facing slopes to reduce sun exposure, planting in shallow soil to reduce water consumption, and introducing controlled or drip irrigation, are possible mitigation strategies.


Other areas not currently suited to winegrowing could become so.

A recent Victoria University of Wellington study reports a lack of specific data and budget constraints meant winegrowers were reluctant to implement adaptation strategies to mitigate against climate change.


The study's author plans to complete regional climate modelling and make it available to viticulturists to inform their business decisions.




* This article has been supplied by Wholesale Landscapes marketing co-ordinator Tom Filmer. It was written in conjunction with the Wholesale Landscapes Horticulture Team.