Shift from steady rain to intense downpours threatening Italian winemaking, claim researchers
The increasing shift in weather patterns from steady gentle rain to more intense, heavy storms in the past couple of decades is threatening Italian winemaking, according to scientists.
The trend towards heavier, more concentrated rainfall – even when the total amount of rainfall is similar - is resulting in earlier harvests, which can prevent grapes from fully developing their complex flavours, and intense precipitation is the second most important factor, after temperature, in predicting when grapes were ready to be picked.
Because the Italian winery studied does not use irrigation or other modern techniques, its harvest records accurately reflect the climatic conditions each year. Scientists gathered local meteorological data and used models to simulate what factors likely most influenced grape readiness.
"Our results are consistent with the hypothesis that the increasing tendency of precipitation intensity could exacerbate the effect of global warming on some premium wines that have been produced for almost 400 years," Piero Di Carlo, associate professor of atmospheric sciences at D'Annunzio University of Chieti-Pescara told Science Daily.
Scientists gathered local meteorological data and used models to simulate which factors were most ikely to impact on the readiness of grapes, with previous studies establishing a link between higher temperatures and earlier grape harvest dates at other European wineries.
Higher rainfall totals can help offset advances in harvest dates caused by rising temperatures, but the impact of rain intensity was not well understood, the scientists said. Steady rains are better for agriculture because heavy storms cause the water to runoff, and plants are less able to absorb moisture.
However, the scientists found that the increase in temperature precipitates more intense rainfall, which further advances the grape harvest date. "We really need to think more broadly about how increases in temperature may have an influence on other variables and how that amplification can affect not only this winery, but all wineries, and in fact all agriculture," Brune said. "I think it's a cautionary tale in that regard."
The winery in the study faced particularly difficult challenges because strategies such as irrigation would alter the way the vineyard has produced its grapes for hundreds of years. Moving to higher elevations may be an option, but land is limited, and such a change could have other, unforeseen impacts on the wine, the scientists said.