Projected wine grape cultivar shifts due to climate change in New Zealand

Climate change has already been affecting the regional suitability of grapevines. This has significant implications for New Zealand. We modeled key crop phenological stages to better understand temporal and spatial shifts in three important regions of New Zealand (Marlborough, Hawke's Bay, Central Otago) for three dominant cultivars (Merlot, Pinot noir, and Sauvignon blanc) and one potential new and later ripening cultivar (Grenache). Simulations show an overall advance in flowering, véraison, and sugar ripeness by mid-century with more pronounced advance by the end of the century. Cross-regional analysis raises the likelihood of the different regional cultivars ripening within a smaller window of time, complicating harvesting schedules across the country. For growers to maintain the same timing of key phenological stages would require shifting planting of cultivars to more Southern parts of the country or implement adaptation strategies. Late ripening cultivars or extended ripening window in cooler regions may be advantageous in the face of climate change.