sexta-feira, 9 de janeiro de 2009

CLIMATE WARMING: CONSEQUENCES FOR VITICULTURE AND THE NOTION OF ´TERROIRS´ IN EUROPE

As for any crop, the impact of an anthropogenic greenhouse effect will include the stimulating effect of increased CO2 concentration on photosynthesis, which will result in increased dry matter production and may lead to noticeable changes in cultural practices. However, it is more likely that the most significant impact will result from an increase in temperature, even if other climatic variables, such as rainfall are also considered. Apart from a significant displacement of the traditional limits for grapevine cultivation, serious questions may arise concerning ‘terroirs’: Will it be possible to keep the same cultivars by adjusting vineyard cultural and enological practices? How might viticulture and wine-making respond to the predicted increase in surface temperature? The warming trend of the last fifteen years in most of Western Europe and especially in France may provide some clues. The phenology of the grapevine has significantly advanced; one to two weeks for anthesis and almost one month for harvest date in the last 50 years. The advance in harvest date also has been accompanied by changes in sugar and acid concentrations. Expressed in terms of the Huglin Index, the increase in temperatures due to global warming will lead to vintages that are more uniform across years. However, there may be a tendency in which the climatic variables of a particular grape growing region will exceed the established limits for grape cultivars strongly associated with that location (‘terroir’). The 2003 growing-season was characterized by very hot weather and drought (similar to the end of century climatic scenarios) and provides evidence that bio-climatic indices do not take into account the possible natural adaptation of some grape cultivars to the predicted changes in climate. Therefore, only the use of more sophisticated tools such as accurate crop models, currently under development, may provide a more valuable perspective on future viticulture. (ver aqui)