Climate Change is likely to lead to increased temperatures in the Western Cape wine regions by 2050, and can affect wine production, said Dr Wilmot James at a lecture he gave as part of the 2011 Darwin Seminars, which were jointly hosted by UCT’s Division of Human Genetics and the African Genome Educational Institute in November.  The lecture preceded the recent COP17 Climate Change Conference 2011 held in Durban.

An edited extract of the lecture appeared in the Cape Argus two weeks ago with the title ‘Will warming yield grapes of wrath?’. It stated that temperatures at the coast are estimated to increase by 1,5°C and by 2-3°C inland by 2050.  Dr James asked what effect these climate changes will have: “How will this affect viticulture? Vines are hardy and produce better fruit when made to struggle. But how much struggle can they take?” He writes that as a region gets hotter, there is less opportunity to make different styles and types of wine.  In the Winelands, there still is the opportunity to develop new vineyards in more temperate and cooler regions, to change viticultural and oenological practices, and to change wine styles, to counter the temperature rise.

According to research conducted by Dr Suzanne Carter, an environmental and geographical scientist at UCT, the following climate change trends can impact on wine production:

*  rainfall will reduce, yet Dr James writes that many farms do not use the full potential of irrigation on their farms.  However, the use of more water will lead to increased cost of production, and may not always be in sufficient supply in times of drought;

*   the length of time between rainy days has been growing over the past 50 years, which means that more rain evaporates than is retained in the soil;

*  heavy rains and floods are not ideal, as too much water is lost, and can ruin crops;

*   higher temperatures have led to better quality wines, but in certain hotter regions this benefit is lost if the grapes ripen too early;

*   a greater concentration of carbon dioxide in the atmosphere creates larger fruit and yields, and improves the water efficiency in vines, but can lead to high sugar levels that can change the flavour and quality of the wines produced.

Dr James does not provide any solutions to the wine industry as to how to counter these effects of Climate Change on wine production.

Dr James was a co-author, with Professor Jakes Gerwel and Jeanne Viall, of the book Grape: Stories of the Vineyards of South Africa’, which focused on the history of the Winelands, highlighted the treatment of staff on some farms, and told stories of winemakers, their workers, exporters, and grape farmers.

Chris von Ulmenstein, Whale Cottage Portfolio: Twitter: @WhaleCottage