Advancement of winegrape maturity continuing for winegrowing regions in Australia with variable evidence of compression of the harvest period

Background and Aims Grapevine phenology is closely linked with growing season temperature. Rising temperature related to anthropogenic climate change has the potential to advance winegrape ripening. This study updated and validated previous research that considered changes to the timing of winegrape maturity and to the warming temperature of the growing season as well as added several new vineyard data sets. Length of the harvest period was assessed to determine if time between harvests of different cultivars has shortened. Methods and Results Vineyard records from 31 vineyard blocks in 13 Australian wine regions, in conjunction with gridded temperature data, were used to assess changes to maturity timing and mean growing season temperature. Trends towards earlier maturity were evident as were increases to mean growing season temperature for all vineyard blocks and regions considered. Trends varied in magnitude as well as by cultivar and region. Compression of the harvest period occurred for half of the regions studied. Conclusions Winegrape maturity in Australia has continued to advance in line with warming temperature, which has implications for grape composition and wine quality. Compression of the harvest period was found in some cases, though varied by region and cultivars grown. Significance of the Study This study validated the trend towards earlier winegrape maturity with continued warming temperature and extended a valuable phenological data set. In light of record warming, earlier maturity is becoming the new norm. The method used to investigate compression of the harvest period in this study is applicable to other winegrowing regions worldwide