The frequency and severity of extreme flood events is expected to increase across Western and Central Europe along the 21st century, according to a new study by Axa.
The study, 2021 European Summer Floods: A warning about the climate-induced increase in flood risk? suggests that in order to mitigate the devastating consequences of these events, the increase in flood risk should be tackled proactively by integrating and continuously updating land use management plans and flood protection strategies, in order to limit the flood exposure and the flood hazard.
According to the report, the International Panel On Climate Change (IPCC)’s AR6 confirms that temperatures will rise in all European area at a rate exceeding global mean temperature changes, similar to past observations.
Because a warmer atmosphere can hold more water vapor, the heavy rainfall events leading to summer floods are expected to become more intense under a warming climate, it adds, noting that climate models show an increase in heavy summer precipitations over Northern and Central Europe between 5% and 25% by the end of the century compared to our recent past (1971-2000).
“Pluvial flooding occurs when the amount of rainfall exceeds the natural and artificial drainage capacity of a region, resulting in local surface floods,” the study adds. “In line with climate model projections of an increase in intense rainfall, which is the main driver of pluvial flooding, the IPCC AR6 projects an increase in pluvial flooding under a 1.5°C and 2°C warming for Western and Central Europe. Furthermore, an increasing trend in river flooding has been observed and is projected a further increase at 2°C and above of global warming.”
Referencing the “very extreme and rare levels of precipitation were observed in western Germany and the Benelux region” in July this year (which the GDV has estimated will cost the German insurance market over 5.5 billion Euros), the Axa study poses the crucial question: how can we mitigate or avoid this situation?
In response, the study suggests that avoiding or mitigating the impact of flooding first and foremost requires a proactive land use management interlinked with flood protection strategies:
“While this event remains exceptional, there is a need for the governments to continuously revise and update the flood risk management strategies, by considering climate change trends on the flood hazard assessments. Another important topic is to recall the risk of flooding despite the lack of occurrence of a flood event in the recent decades. This can lead to the underestimation of the flood hazard, resulting in land development in the flood plain (and therefore an increase in the flood risk).”
Beyond this proactive approach, it adds, adopting a reactive and preventive approach based on alerting and business continuity plans can help to mitigate the flood risks in exposed areas, limiting the consequences of flood events.