The challenge of unprecedented floods and droughts in risk management

A study has shown that gearing risk management measures to the worst-case event experienced to date is not enough to reduce impacts from unprecedented events.

Just because you haven't experienced something doesn't mean it can't happen. This insight also applies to natural hazards such as floods and droughts. A study published in the scientific journal Nature has shown that gearing risk management measures to the worst-case event experienced to date is not enough to reduce impacts from unprecedented events.

Floods and droughts can cause severe damage. Their intensity is increasing in many parts of the world and they are becoming more frequent. Appropriate risk management can reduce the impact of such natural hazards if the causes of the increasing damage are known. However, this has so far been hampered by a lack of empirical data.

Now, a large-scale international collaborative effort by researchers from the International Association of Hydrological Sciences, led by Heidi Kreibich of the German Research Centre for Geosciences Potsdam (GFZ), has compiled a unique data set. Almost one hundred authors were involved in the study of two successive extreme flood or drought events in the same area. The focus was on regions with large differences in population structure, socio-economic, climatic and hydrological conditions on all continents. 45 extreme event pairs (droughts or floods), separated by an average of 16 years, were thus compiled.

The analyses confirmed the obvious assumption that adequate risk management generally helps to reduce damage. The problem lies elsewhere: if extreme events occurred in a region that had never experienced an event of similar intensity before, it was particularly difficult to mitigate the effects.

Heidi Kreibich explains this with two factors. First, infrastructures such as dams and reservoirs have an upper design limit up to which they are effective. Once a threshold is exceeded however, they become ineffective. Second, risk management is usually introduced or adjusted reactively after major floods and droughts, while proactive, anticipatory strategies without precedent are rare. According to Kreibich, the reason for this behavior lies partly in a cognitive bias related to the rarity and previous uniqueness of these extreme events, as well as in the nature of human risk perception: events that one has already experienced oneself are also more likely to be expected again in the future.

However, the team also identified two success stories in the study in which the damage was less despite a higher hazard in the second event. These were floods in Barcelona (1995 and 2018) and on the Danube in Austria and Germany (2002 and 2013). In Spain, the amount of damage fell from 33 million euros to 3.5 million, while the Danube floods caused damage of 4 billion euros in 2002 and 2.3 billion in 2013. In both cases, the second events were originally worse: they lasted longer or it rained far more.

According to the researchers, three success factors were crucial: effective governance of risk and emergency management, high investment in structural and non-structural measures, and improved early warning and real-time control systems. Heidi Kreibich says: "We believe that applying these success factors can counteract the current trend of increasing damage from extreme events under climate change conditions."
 

Original Study:  Kreibich, H., Van Loon, A.F., Schröter, K. et al. The challenge of unprecedented floods and droughts in risk management. Nature (2022). https://doi.org/10.1038/s41586-022-04917-5

Scientific contact

Group Leader
Priv. Doz. Dr. Heidi Kreibich

Media contact

Additional News

[Translate to English:] Michael Pons knieend an einer felsigen Meeresküste. Im Hintergrund das Meer.

“Outstanding Student and PhD candidate Presentation (OSPP) Award 2022" for Michaël Pons

[Translate to English:] Lila Flagge wehend über einem Dachgiebel

Interviews on the occasion of the Purple Light Up 2022

Obituary picture of Dr. Kemâl Erbas.

Obituary Dr. Kemâl Erbas

Two profile photos and in between the logo of BMWK and a symbol image for a text document.

Important signal for the expansion of deep geothermal energy

German map with quality-checked data points, shown as columns

A new heat-flow analysis shows higher values for Germany

P. Martinez-Garzon in a forest next to a giant split rock

Dr. Patricia Martinez-Garzon wins ERC Starting Grant for her project QUAKE-HUNTER

Map of Türkiye with the marked epicentre of the earthquake in the northwestern part of the country

Background on today's earthquake in northwest Türkiye

Topography map of the alps.

What is driving the Alps upwards?

Groupp picture ICDP/IODP Kolloquiums

Joint IODP/ICDP-Colloquium at GFZ

Teachers in lecture hall during lecture

"Extreme Events in the Earth System" - 20th "System Earth" Autumn School

Two young researchers stand in front of trees holding their certificates, next to them stands Ludwig Stroink, who awarded the certificates.

“GFZ Friends” honours Theresa Hennig and Lei Wang with the “Friedrich-Robert-Helmert Prize…

Satellite image of a desert area: Colorful spots show different minerals.

German environmental satellite EnMAP: start into regular operation

On the left, a measuring tower in a low overgrown tundra landscape.

More methane from Siberia in summer

[Translate to English:] Profilfoto mit schwarzem Rahmen von Henning Francke

Obituary: Henning Francke

Group photo with projekt responsible

Making geodata interoperable and suited for curiosity driven research: GEO-INQUIRE project…

Schema Energiebereitstellung durch Geothermie

European Geothermal Congress from 17 to 21 October 2022 in Berlin

Gruppenfoto PAM

International Conference on Polar and Alpine Microbiology

Leni Scheck Wenderoth

“AWG Professional Excellence Award” for Magdalena Scheck-Wenderoth

Ausbildung am GFZ

Berufsausbildung und duales Studium am GFZ

Dr. Ute Weckmann during the opening speech of the workshop

Dr. Ute Weckmann takes over the chairmanship of IAGA Division VI

Anke Neumann aon a boat during a research trip

Dr Anke Neumann is a Senior Humboldt Research Fellow

Earth Model

New DFG priority programme on deep Earth evolution over geologic time

Logo of the Helmholtz Innovation Labs: written words only

Successful interim evaluation of the two Helmholtz Innovation Labs at the GFZ

Schematic of plunging Earth plates under the ocean with water transport and the Al molecules involved: This is how water migrates deeper into the Earth than previously assumed.

Water is seeping deeper into Earth than expected

From the air, a view of Istanbul, a city of millions, and the surrounding sea.

"Earthquakes don’t occur out of nowhere"

Group photo with all the people who attended the farewell

Honouring Prof. Onno Oncken with a scientific colloquium

DEUQUA Logo mit Mammut und Friedenstaube

DEUQUA 2022 Tagung am GFZ

PAW Logo

Postdoc Appreciation Week Germany

Building, photo taken in winter, Isaac Newton Institute

Simons Scholarship for Dr Monika Korte

Die Verteilung der seismischen Stationen auf einer Karte der Region.

How deeply does Eifel volcanism sleep?

back to top of main content