Projections of Suitable Wine Growing Regions and Varieties: Adaptation in Space or Place?

Abstract:

Winegrapes (Vitis vinifera L) are the most valuable horticultural crop in the world with nearly eight million hectares of vineyards in cultivation. Different varieties of winegrapes (e.g., Grenache or Syrah) exhibit an unprecedented amount of phenological and genetic diversity for a cultivated species, which is an important resource to buffer against climate change. Matching phenological strategies of the different winegrape varieties to a particular climate is a fundamental aim for every vineyard manager, especially in the face of significant climatic shifts in many winegrape growing regions. Yet current projections of suitable winegrape growing regions based on future climate scenarios are limited in their utility, as they do not consider the possibility that other varieties better suited to a future climate could be planted within an existing region. For our projections, we built phenological models for the nine most-planted winegrapes globally, which constitutes over 40% of all planted hectares, using a global dataset of budburst, flowering, veraison and maturity. These models were then used to characterize the growing range of 1300 globally planted winegrape varieties. Combing these models with climate projection models under RCP 4.5 and 8.5 emission scenarios we examined future distributions of suitable wine growing regions, as well as the turnover of suitable varieties within existing regions. In some regions of the world, predicted climate change will not significantly alter the varieties that are able to grow, while in others there will need to be shifts in the region itself or in the varieties that are currently planted. Some regions will also see a significant increase in the number and diversity of varieties that can be grown. Our results suggest the need to utilize the full range of winegrape diversity available when considering adaptive strategies in response to changing climates.