Emerging Links Between Droughts, Heatwaves and Extreme Precipitation in Europe and the Mediterranean basin

Extreme climate hazards can occur in isolation or interact as concurrent, compound or transitional events, amplifying their impact on key socioeconomic sectors such as agriculture, tourism and health. In Europe and the Mediterranean basin region, these interactions pose significant risks over the densely populated regions which are highly vulnerable to the combined occurrence of climate hazards. Hence, the study of this aggravating issue in the context of global warming emphasizing the analysis of concurrent, compound, sequential and transitional climate extreme events is crucial to better comprehending their relationships and improving early warning systems and adaptive strategies in emerging climate hotspots.  

In this study daily high-resolution datasets from different sources, (ROCIO-IBEB, EMO1, CERRA, EFFIS, ICV, ERA-5 and MED-REP-L4), have been used to identify atmospheric and marine heatwaves, droughts, wildfires, extreme precipitation events and extreme wind, as well as to detect emerging hotspots.  

Our findings over specific Mediterranean climate change hotspot such as the Valencia Region in eastern Spain reveal a rising frequency of concurrent hazards, with droughts emerging as a key driver of both summer wildfires and extreme autumn precipitation. Besides, our results also indicate an increasing influence of Mediterranean Sea warming on both maximum 2-meter air temperature over land and extreme autumn precipitation highlighting the relevance of the welldocumented Mediterranean SST increase on climate extremes. Besides, relationships among key climate variables have been studied using different methodologies, such as lagged correlations and normalized information flows, to estimate climate factors influences on climate extremes.  

The extension of the analysis to Europe and the Mediterranean basin yielded results that were consistent with those of the regional analysis. It has been determined that the proportion of hazards and drivers that compound forest fires is similar between in and out identified hotspots. Furthermore, AHW-drought and drought-AHW transitions have been analyzed, with heightened intensity observed in the latter. Evidence suggests that drought-EPE transitions occur most severely in regions where droughts and EPEs are most intense as a singular event, too. Regarding MHW analyses in the northeastern Atlantic Ocean and Euro-Mediterranean seas, the results reveal the presence of large high-intensity MHW hotspots over northern seas, especially in the Artic Sea, in contrast with the localized Mediterranean hotspots. 

The present study seeks to determine whether areas susceptible to dry-heat-wet hazards are concomitantly exposed to forest fires and floods. Furthermore, an ongoing analysis of flooding risk will provide additional information on a local scale, which is crucial for identifying interactions among climate hazards, and for evaluating potential risks and vulnerability over these areas.