Cascading effects of the 2018-2019 German drought: empirical evidence from media reports

During 2018-2019 Germany experienced a severe drought which affected 90% of its territory, especially the North and the East. Its consequences have been far-reaching for agriculture, forestry and aquatic ecosystems. Low water levels, including at the Rhine, impaired waterborne transportation, which led to increased energy prices. Furthermore, nuclear power stations lowered their production or shut down and hydropower and industrial outcomes were reduced. Despite these consequences, the inter-sectoral effects of the 2018-2019 German drought are still largely unexplored due to the inherent complexity in their assessment.

This study seeks to close this gap by providing a methodology for characterizing drought impacts and its interdependencies at the district level. The proposed approach allows understanding the compounding and cascading consequences of long-term droughts as a socio-economic and ecosystem disturbance. To this end, we conducted a comprehensive analysis of the 2018-2019 drought impacts across Germany based on a quantitative content analysis of 5.074 newspaper articles published between April 2018 and August 2019. A total of 4.878 unique impacts within 25 sub-categories were identified. These were then analyzed over time and space, aiming to identify emerging trends. Additionally, network analysis was employed to better understand the dynamics and interrelationships between the cross-sectoral impacts. Validation was conducted by carrying out a correlation analysis between the obtained results and the monthly soil moisture index, crop losses statistics and the population drought awareness.

The developed coding system was in 95.4% of the cases accurate, meaning that the proposed approach can provide reliable information for classifying a large amount of data. Results highlight the complex nature of assessing drought impacts, describing the propagation of drought and related direct and indirect impacts across various sectors. Overall, agriculture was severely affected in most of the districts in 2018 whereas impacts on forestry were predominant in 2019. As expected, the reduction of crop productivity was closely interlinked with impacts such as early harvesting of crops, shortage of feed, reduction of livestock, economic losses and need for government assistance. The frequency of the impacts varied regionally, with losses to industry concentrated in Nordrhein-Westfalen and impacts to livestock farming concentrated in Sachsen-Anhalt. To the best of our knowledge, the collected and analyzed impact report data constitutes the first attempt to quantify the cascading effects of drought impacts across NUTS 3 regions. The proposed methodology can be applied to other study areas and results can support policy-planning and inform drought impacts forecasting.