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New Study Shows Declining Risk & Increasing Resilience To Extreme Weather In France

Weather and Climate Extremes, 28 July 2018

This risk factor for French residents of cities stricken by a disaster has been falling with every passing decade.

Abstract: Using an exhaustive administrative database, we assess the impact of extreme weather events over French cities between 1982 and 2017. We identify numerous non-catastrophic disasters, thereby improving coverage wrt. the existing literature. Counting residents of cities stricken by a disaster, we find that in the long run, there were 22 residents affected every month per thousand population. This risk factor has been falling by 5 fewer people with every passing decade. France has thus improved its preparedness to natural disasters even though the seaboard regions fare worse than the northern region, most likely because of heightened urban pressure in hazardous areas by the seaside. Tropical territories are more at risk than the temperate European mainland, from a different mix of events. The full economic cost of natural disasters is estimated at 22 € per capita per year and represent a small fraction of property insurance premiums. Residents from safer areas currently subsidize those living in riskier areas. To be more effective, preventive investments should be directed towards the main cities. […]

Result 2. The raw incidence of floods over mainland France is stable over the last 35 years. Once we account for the heightened population pressure, it displays a negative trend.

[…] The results are reported in Table 3 allow to conclude that both rates of forest fire destruction display a significative downward trend, the anthropogenic rate νt fell from about 5‰ to 2‰ (over the period 1973–2017) while the natural rate μt is about one hundred times smaller and likewise falling. The latter fact proves that the incidence of natural forest fires over the French mediterranean seaboard is receding over the last 44 years….

Given that recurring natural disasters such as floods and storms have a strong seasonal pattern, we study the 12 month moving average. The flat dashed line displays the overall mean indicating that over the long run 22‰ of the continental French population is impacted every month by a natural disaster. The linear trend line, shown in red, is markedly sloping down: with every passing decade, there are 4‰ fewer residents affected by disasters every month.


8. Conclusion

Our study of natural disasters over France leverages a (quasi) exhaustive administrative database of disaster declarations at the township level. Assuming firstly, that the criteria for declaring a natural disaster has remained unaltered and secondly, that proxying township victims by the residents count is adequate, we obtain a number of results.

Firstly, the frequency of natural disasters is fifty times over that of catastrophes collected by traditional rosters, thereby unearthing the many smaller disasters that impact millions of people’s lives. Regarding climate change, the incidence of floods over mainland France is found to be stable over the last 35 years and even falling once we account for the heightened population pressure.

Next, we find that France has improved its preparedness to natural disasters even though the seaboard regions fare worse than the northern continental region, most likely because of heightened urban pressure in risky areas by the seaside. French tropical territories are found to suffer a slightly greater hazard risk in the long run when compared to the temperate climate of mainland France. This finding warrants the insistence of tropical islander nations to tackle urgently the risks associated with climate change, particularly regarding prevention and resilience. However, the very fact that exposure in tropical France is commensurate with the “rich and safe” mainland part of the country means that the task awaiting islander nations is achievable (which the examples of Bangladesh and South Korea also demonstrate).

Moving to economic considerations, we find that the occurrence of natural disasters does not impact meaningfully either employment or growth. The estimated full economic cost of natural disasters is a small fraction of current expenses for private property insurance, making the management of a disaster risk scheme quite manageable even for developing countries. Regarding fairness, the current principle of equalizing natural hazard risk among French citizens sees the majority, living in safe areas, subsidizing a minority living in riskier areas both for compensation and for preventive investments. Under the alternative principle of protecting the greatest number of people, investment would be directed at the main cities under a significant risk. This view would likely be the one favored by cash-constrained developing countries (and is gaining traction in France itself).

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