European Flood Risk Could Double By 2050
New research projects a massive increase in financial losses due to floods in Europe over coming decades as the risk of flooding doubles, concludes a paper published online this week in Nature Climate Change.
Major floods, such as those that affected countries across Europe in June 2013 and that are currently afflicting parts of southern England, are expected to become more common under climate change, putting increasing pressure on disaster risk finance at both the national and the EU level.
Brenden Jongman and colleagues show that peak monthly water discharges from European river sub-basins are a good indicator of flood risk. They find a high degree of correlation between peak discharges across sub-basins, which is due to large-scale weather patterns. This means that different rivers often flow high at the same time, threatening floods across large regions. The researchers also model present and future potential flood losses, taking into account both projected climate change and socio-economic development. Their computer simulations suggest that average annual flood losses could increase by 500% from now to 2050, with the frequency of extreme events — leading to losses due to floods of the magnitude suffered in 2013 (€12 billion) — approximately doubling over that period.
Although the magnitude and distribution of losses can be contained by investing in flood protection, and their effects mitigated by increasing insurance coverage or by expanding current public compensation funds, the results of the study show that these measures have vastly different efficiency, equity and acceptability implications. The authors conclude that it may become increasingly necessary for European counties to help each other financially when major floods strike.
Here is the text of a news release issued by the International Institute for Applied Systems Analysis which discusses this research.
Losses from extreme floods in Europe could more than double by 2050, because of climate change and socioeconomic development. Understanding the risk posed by large-scale floods is of growing importance and will be key for managing climate adaptation.
Current flood losses in Europe are likely to double by 2050, according to a new study published in the journal Nature Climate Change by researchers from the International Institute for Applied Systems Analysis (IIASA), the Institute for Environmental Studies in Amsterdam, and other European research centres. Socioeconomic growth accounts for about two-thirds of the increased risk, as development leads to more buildings and infrastructure that could be damaged in a flood. The other third of the increase comes from climate change, which is projected to change rainfall patterns in Europe.
“In this study we brought together expertise from the fields of hydrology, economics, mathematics and climate change adaptation, allowing us for the first time to comprehensively assess continental flood risk and compare the different adaptation options,” says Brenden Jongman of the Institute for Environmental Studies in Amsterdam, who coordinated the study.
The study estimated that floods in the European Union averaged €4.9 billion a year from 2000 to 2012. These average losses could increase to €23.5 billion by 2050. In addition, large events such as the 2013 European floods are likely to increase in frequency from an average of once every 16 years to a probability of once every 10 years by 2050.
The analysis combined models of climate change and socioeconomic development to build a better estimate of flood risk for the region. IIASA researcher Stefan Hochrainer-Stigler led the modeling work on the study.
He says, “The new study for the first time accounts for the correlation between floods in different countries. Current risk-assessment models assume that each river basin is independent. But in actuality, river flows across Europe are closely correlated, rising and falling in response to large-scale atmospheric patterns that bring rains and dry spells to large regions.”
“If the rivers are flooding in Central Europe, they are likely to also be flooding Eastern European regions,” says Hochrainer-Stigler. “We need to be prepared for larger stress on risk financing mechanisms, such as the pan-European Solidarity Fund (EUSF), a financial tool for financing disaster recovery in the European Union.”
For example, the analysis suggests that the EUSF must pay out funds simultaneously across many regions. This can cause unacceptable stresses to such risk financing mechanisms. Hochrainer-Stigler says, “We need to reconsider advance mechanisms to finance these risks if we want to be in the position to quickly and comprehensively pay for recovery.”
IIASA researcher Reinhard Mechler, another study co-author, points out the larger implications arising from the analysis. He says, “There is scope for better managing flood risk through risk prevention, such as using moveable flood walls, risk financing and enhanced solidarity between countries. There is no one-size-fits all solution, and the risk management measures have very different efficiency, equity and acceptability implications. These need to be assessed and considered in broader consultation, for which the analysis provides a comprehensive basis.”
End of news release.
Recent major flood disasters have shown that single extreme events can affect multiple countries simultaneously, which puts high pressure on trans-national risk reduction and risk transfer mechanisms. So far, little is known about such flood hazard interdependencies across regions and the corresponding joint risks at regional to continental scales. Reliable information on correlated loss probabilities is crucial for developing robust insurance schemes and public adaptation funds, and for enhancing our understanding of climate change impacts. Here we show that extreme discharges are strongly correlated across European river basins. We present probabilistic trends in continental flood risk, and demonstrate that observed extreme flood losses could more than double in frequency by 2050 under future climate change and socio-economic development. We suggest that risk management for these increasing losses is largely feasible, and we demonstrate that risk can be shared by expanding risk transfer financing, reduced by investing in flood protection, or absorbed by enhanced solidarity between countries. We conclude that these measures have vastly different efficiency, equity and acceptability implications, which need to be taken into account in broader consultation, for which our analysis provides a basis.
Jongman, B, S Hochrainer-Stigler, et. al. (2014). Increasing stress on disaster risk finance due to large floods. Nature Climate Change (letter). doi: 10.1038/nclimate2124
Read the abstract and see the paper here.
Press release from Nature.
News release from the the International Institute for Applied Systems Analysis issued via the EurekAlert! Service of the AAAS here.