環境：最近の数十年間に増加したヨーロッパの洪水

The past 30 years have been one of the most flood-rich periods in Europe according to an analysis of the last 500 years of flooding events published in Nature. The paper suggests that this period differs from other historical events owing to the seasonality, extent and air temperatures associated with the flooding. The findings could help to improve flood-risk assessment and management strategies.

In recent decades, flooding in Europe has caused large economic losses, and previous studies have indicated that flooding events are increasing in some regions. However, it is unclear whether this current trend is characterized by more frequent and bigger floods than usual and whether it differs from flood-rich periods in the past.

Günter Blöschl and colleagues constructed a database of 9,576 flooding events using historical records, including legal records, newspapers, and official and private correspondence, for 103 river reaches across Europe from 1500 to 2016. The authors identify nine flood-rich periods that have occurred over Europe’s history at regular intervals. Previous flood-rich periods tended to be colder than the intervening years, and the risk of seasonal flooding was similar throughout. However, when they analysed the most recent flood-rich period, 1990–2016, they found that it was around 1.4 °C warmer than the intervening years. They also found that the risk of seasonal flooding, especially in the summer, also increased during this period.

The authors indicate that although their data stop in 2016, the flood-rich period may have continued. They highlight the need for flood-risk management and assessment tools that can account for these changes.