The climate of the Douro: structure, trends and mitigation and adaptation responses to a changing climate

Abstract

The Douro Wine Region has a long history of wine production across a diverse array of landscapes and climates. This research examined the climate structure, variability and trends of climate in the region with the goal to establish a baseline understanding from which changes in climate can be made. Spatial climate data for 1950-2000 shows that the Huglin Index for the region averages 2160, however, due to the diverse terrain, the region spans five different classes suitable for viticulture being 50% a Warm Temperate climate, 35% a Temperate climate, 10% a Warm climate, and 5% a Cool or Very Cool climate. Three long-term stations in the region show greater warming in minimum compared to maximum temperatures with rates ranging from 1.2°C to 3.6°C during 1967-2010. Analysis of extreme events for the three stations reveals significant changes for both maximum and minimum temperature extremes, with overall warmer nights, warmer days, a general decline in the diurnal temperature range, a higher number heat stress events, some evidence for longer warm spells, and a clear reduction in cold spell durations. The region is also dominated by circulation features of the Atlantic-European sector that produce a strong winter-summer contrast in both temperatures and precipitation. Given the few trends in weather regimes, but significant trends in annual, growing season, and dormant season temperatures, the results point to a general warming that is not being significantly driven by regional circulation changes. Future climate conditions in the Douro Wine Region are projected to warm and dry over all emission scenarios (B2, A1B, and A2) and for each time slice examined (2020, 2050, and 2080). However, the Douro Wine Region is rich in landscape and plant characteristics that may help mitigate the deleterious effects of climate change. By following sustainable approaches and being innovative across the entire production system the Douro Wine Region has and will continue to reduce its vulnerability and increase its adaptive capacity in the face of a changing climate.