The complex response of Mediterranean viticultural systems to climate change: a case study from France and Australia

Climate change could put at risk viticultural areas situated at the hotter margins of Vitis vinifera growth climatic range. We focus on two such regions with a Mediterranean climate (CSb type in Köppen classification): Côtes-du-Roussillon in southern France and McLaren Vale in South Australia. They share a relatively similar recent climate evolution. Based on data from two synoptic weather stations, Perpignan (France) and Adelaide (Australia), with daily time series running from 1956 to 2010, we identified changes in temperatures and precipitation patterns, especially an increase of maximum temperatures, of the Huglin Index and Cool Night Index. According to climate models (data from DRIAS project in France, CSIRO Mk3.5 model in Australia) this tendency is likely to continue in the future. In these two regions, two red varieties are mainly grown: Grenache and Shiraz, as they are relatively well suited to Mediterranean climate and to market demand in volatile global markets. Based on twenty in-depth semi-structured interviews in both regions, we identified that vineyard management practices –current and planned for a near future, are based in their vast majority on economical considerations. Concerns of producers include: maintaining income and market position by producing optimal yields, a constant wine style and quality and a diversified offer. In addition, producers feel they have to deal with an increasing uncertainty regarding climate variability, confirmed by climate data. Adaptation strategies of producers to various types of changes, including climate change, take into account a multiplicity of factors, in which climate change is often not the main concern. Two opposite systems of legislation and cultural traditions in the two regions also make the choice and implementation of adaptation strategies very different. Thus the sensitivity of viticultural systems to climate change depends strongly on non-climatic factors.