Assessment of Selected Climate Indicators Across the Elbe River Basin to Analyse Changes in Climate Extremes and their Effects

Abstract The Elbe River basin, located in Germany and the Czech Republic, is vulnerable to changing climate extremes and has experienced multiple natural hazards over the years. Therefore, assessing the impacts of climate change on extreme events across the basin is vital to adapt and improve resiliency. Unfortunately, data on variations of climate extremes usually have a very coarse spatial resolution, which limits any regional application. Thus, to improve the quality and availability of climate extreme data, we estimated climate indices mostly from the Expert Team on Climate Change Detection Monitoring and Indices (ETCCDI). The indices were based on temperature, precipitation, and agrometeorology. They were estimated on a regional scale using an ensemble of high-resolution (12.5 km) climate model data. Two different climate scenarios, rcp26 and rcp85, were considered. The eight climate indices estimated in this study (1) help better understand the variation in climate extreme events, (2) identify vulnerable areas, and (3) analyse their impact on natural resources (e.g., agriculture). The results showed that by the end of this century, temperature-based extremes will increase with minimal spatial variation for summer months, while precipitation-based extremes show that conditions which promote flood events will increase in the headwater regions located in the South of the basin. Additionally, agrometeorological indicators imply that factors favourable for agricultural processes will become more common, but their trend and seasonal analysis show extreme events will hinder the application of best farming practices. Lastly, policy recommendations for adaptation measures (e.g., green infrastructure) have been highlighted in this study to address different climate risks, enabling resilient resource management across the basin. Graphical Abstract In this study, we prepared and analysed eight climate indices datasets using projected climate model data from the European Coordinated Regional Downscaling Experiment (EURO-CORDEX) on a subbasin scale. The indices were based on temperature, precipitation, and agrometeorology and were estimated for two different climate scenarios rcp26 and rcp85. The results from our study further highlight (1) the complex impacts a warming climate will have on the intensity of extreme events, (2) the effect of changing extremes on regional natural resources, and (3) help identify vulnerable regions. The results showed that by the end of this century, temperature-based extremes will increase with minimal spatial variation for summer months, while precipitation-based extremes show that conditions which promote flood events will increase in the headwater regions located in the South of the basin. Additionally, agrometeorological indicators suggest that factors favourable for agricultural processes will become more common; however, their trend and seasonal analysis indicate that extreme events will hinder the application of best farming practices.