Effects of Climate Change and Phenological Monitoring of the Indigenous Godello Variety in a Territory of Heroic Viticulture and Biosphere Reserve

Abstract

In the year 2023, the phenological behaviour of the indigenous Godello variety of vineyard was evaluated at Souto Chao, located in the north-west of the Iberian Peninsula, which is a wine-growing region and considered as the place of Designation of Origin (Ribeira Sacra DO). In 2017 and 2018, a similar study was carried out on the same plants of Godello variety, but this latest study aimed to ascertain the nature and extent of changes in the crop’s phenology within the timeframe between the initial two years analysed (2017 and 2018) and the present year, 2023. The scale used for study was the one proposed by the BBCH of Lorenz. The average length of the vegetative cycle in the initial two years was 167 days (161 and 174 days in 2017 and 2018, respectively), while in 2023 it was 164 days. The results obtained show a longer vegetative cycle in 2018, with significant differences between the beginning and end of the different phenological phases. Of the three years analysed, 2018 stands out showing a significant deviation from the average. Moreover, there is a close relationship between the phenological behaviour of the Godello variety and certain climatic parameters. Temperature is the most decisive factor, specifically the average annual minimum temperature, which was lower in 2018. In addition, the highest thermal requirements were observed in that same year, with figures slightly above 5200 GDD. As for the historical harvest dates, there are only two recorded years in which the grape harvest took place in August, namely in 2017 and 2023. In this geographical region, the grape harvest, with the exception of the two years mentioned above, usually takes place in September, as was the case in 2018. The vulnerability of viticulture to climate change depends on the magnitude of the impacts. Global warming is the great challenge for the wine business and will force changes in vineyard management to curb its most damaging effects. Its most obvious effects, such as the rise in average global temperature or the decrease and redistribution of rainfall, increasingly in the form of occasional and intense storms, have gone from perception to certainty.