Modelled impact of future climate change on the phenology of winegrapes in Australia

Projected impacts from future warming on grapevine phenology have been modelled for two important varieties across six representative wine‐growing regions in Australia. Various regional warming projections are based on a range of future greenhouse gas emission scenarios and patterns of climate change from a suite of climate models. Results are compared and contrasted regionally and the sensitivity of grapevine phenology to different climate futures is assessed. Impacts on budburst vary from region to region. Cabernet Sauvignon budburst in Coonawarra is projected to occur earlier by four to eight days in the year 2030, and by six to 11 days in 2050. Season duration (from budburst to harvest) is compressed in all regions studied and harvest is earlier in most cases. Given the highest warming scenario, harvest could be 45 days earlier in Coonawarra by 2050. Some regions may be adversely affected by the chilling requirement not being met in future warmer climates. For example, in the Margaret River region budburst is projected to be later. An important finding of this analysis is that harvest is projected to occur both earlier in the year and in a warmer climate, i.e. a dual warming impact. Harvesting in warmer temperatures can negatively impact grape quality.