Que Sera, Shiraz?

This development may lead to the creation of a whole new cadre of climate change activists. (GW)

Vineyards count days to change in flavours

By Nicky Phillips
Sydney Morning Herald
July 25, 2011

SOME of Australia's favourite vineyards will be forced to move or produce wines that taste markedly different because of climate change, a viticulture expert said.

Rising temperatures have already affected many grape growers, with fruits ripening earlier each year.

But the impact of a warmer climate will have benefits, says Snow Barlow from the University of Melbourne, who will discuss the impacts of a warming planet on the wine industry at a public forum in Melbourne tonight.

''It could lead to exciting new styles of wine,'' Professor Barlow said.

To assess the changes in Australian wine regions over the last three decades, Professor Barlow's team looked at the vintage records collected by winemakers from more than 40 vineyards. They found that grapes ripen, on average, two days earlier each year.

In Coonawarra, South Australia, a region famed for its cabernet sauvignon and shiraz, farmers are harvesting their grapes 3½ days earlier, while in the Barossa Valley, grapes sprout 1½ days early, Professor Barlow said.

Changes experienced by the grape industry were a sign of things to come for the rest of agriculture, he said. ''We see [wine grapes] as a canary in the coalmine. Because [they are] so sensitive to climate, you'll see changes in the grape industry before you'll see changes in other industries.''

As well as early ripening, a warming climate will also affect the characteristics associated with specific wines.

The molecules that make the grassy flavours of New Zealand's Marlborough sauvignon blanc are not expressed as much in warmer climates, Professor Barlow said. Wine growers, whose produce is vulnerable to climate change, will have two choices, he said. ''You can either change the style of wine you make, or move.''

Brown Brothers, a Victorian family-owned wine company, has said climate change was one of the main reasons it bought land in Tasmania.

Advances in wine science meant producers were closer to identifying more molecules that give wines their unique characteristic, and the climate conditions which favour their development. ''That gives us much more information about where to go if we want to produce wines with those qualities,'' Professor Barlow said.

As wine grapes had little genetic diversity, it was unlikely they would have much capacity to adapt to changes in their environment. ''But there is such an enormous diversity of places to grow grapes that, if people want the styles of wines they have now, the industry will probably produce them, but from different regions.''