South Africa, California and Australia might be better equipped to adapt to a changing climate than Old World wine producers, but a looming water scarcity poses the greatest challenge to Cape winemakers. Leonie Joubert of www.wine.co.za reports on the 'Changing Environments' seminar held in Cape Town last week.

Sangiovese vines are blooming 12 days earlier in Conegliao, Italy. Bud break is coming 14 days earlier to Riesling in Alsace. Veraison is coming to Slovakian Chardonnay vines 19 days sooner than usual. Meanwhile in Bordeaux, harvesting of Merlot grapes is starting 16 days ahead of the historical average.

These are some documented responses of vineyards to changes in climatic conditions in the historical centres of Old World wine production because of increased atmospheric pollution during the past 350 years.

"Increased carbon dioxide in the atmosphere will result in increased temperatures in most areas of the planet," Prof. Hans Schultz of the Geisenheim Research Institute told seminar delegates.

"We will see changes in precipitation, where many places will experience an increase in winter rainfall and a decrease in summertime rainfall. Extreme weather events will occur along with an increase in solar radiation," Schultz said.

Climate change modelling, mostly conducted by the United Nations Intergovernmental Panel on Climate Change (IPCC), indicates that polar regions will warm faster than the mid-latitudes. Meanwhile the northern hemisphere will warm faster than the southern hemisphere because of the greater landmasses occurring north of the equator.

The IPCC predicts an increase of between 1.4°C to almost 5.8°C during the next century. Increasing temperatures globally will result in greater evaporation from the ocean and large bodies of fresh water. Since the "what goes up, must come down" principle of physics applies equally to water, this means an overall increase in rainfall.

Increased rainfall, however, will not occur uniformly across the globe.

Schultz believes that South Africa, along with California and Australia, is better equipped to adapt to shifting climate than Old World producers. Already considerable irrigation infrastructure is in place, and with fewer people in the decision making chain, the industry can push through the kind of legislation that will allow for adaptation.

Water shortages, though, remain the greatest threat to the security of the wine industry. Schultz predicts that in the struggle between urban and agricultural demands for water, the urban environment will win and municipalities will cut off water to farmers to meet growing demands of the metropole. Schultz said that as much as 81% of the premium vineyards in the US will be lost due to water shortages.

For the complete story, go to http://www.wine.co.za