The summer 2022 drought in the Po valley (Italy): a glimpse of the future climate?

The Po valley (northern Italy) hosts important economic activities and contributes to a significant fraction of the national agricultural production. On its coastal region (the Po Delta) reclaimed agricultural lands coexist, largely below the mean sea level, with natural areas of outstanding environmental relevance. Besides affecting the socio-economic and ecological dynamics within its basin, the modulation of the hydrological regime of the Po river also plays a major role in controlling the oceanographic processes occurring in the northern Adriatic Sea, from coastal circulation to deep ventilation and thermohaline circulation at the Mediterranean scale. In this framework, the severe drought that affected large areas of Europe in Spring and Summer 2022 hit the Po river system with particular intensity, with heavy impacts on productive activities and extensive saltwater intrusion in the coastal areas.

By means of observed discharge records and precipitation data from reanalysis and climate models, this contribution presents an analysis of the 2022 drought event, investigating its exceptionality in the recent past climate and exploring its possible recurrence in future conditions. Ensemble projections of rainfall regimes on the Po River basin in two climate change scenarios (RCP4.5 and RCP8.5) show that persistent negative rainfall anomalies like the one that characterised the 2022 event will unlikely become typical features of the future climate, but could remarkably increase their frequency. Furthermore, the impacts of these events will be magnified by rising temperatures, enhancing evapotranspiration rates in agriculture and water demand. Particularly in severe climate change scenarios, heavier and more frequent episodes of water shortage, combined with a rising sea level, are expected to intensify the pressure of saltwater intrusion in the coastal areas of the Po Delta, increasing the risk for environmental impoverishment and for loss of agricultural lands.

Besides investigating in a climate change perspective a recent severe event that struck an important economic and ecological region, the present contribution aims at stimulating the development of advanced climate change adaptation strategies in riverine, deltaic and estuarine systems, emphasizing the importance of an integrated source-to-sea approach to this process.