In an international collaboration consisting of researchers from the International Association of Hydrological Sciences (IAHS), led by Heidi Kreibich from the German Research Center for Geosciences (GFZ), Anne van Loon, Philip Ward, Maurizio Mazzoleni, Marlies Barendrecht and Marleen de Ruiter from The Institute for Environmental Studies (IVM) demonstrated that good risk management can help address the potential impacts of unprecedented floods and droughts. In addition, the researchers observed two success stories that may reduce the current trend of increasing damage from extreme events under climate change conditions. The research was recently published in the scientific journal Nature.
Drought in the Netherlands
We are not well prepared for very extreme natural disasters, while such extremes as the drought now in the Netherlands will occur more often. Good risk management makes us less vulnerable to these types of natural disasters, but the consequences are still increasing. Reducing the impact requires a better understanding of the causes of the changing effects of past disasters. Until now, this could not be determined due to a lack of empirical data.
A unique data set of two successive extreme flood and drought events in the same area was compiled and studied by the researchers. They studied regions with large differences in population structure, socio-economic, climatic and hydrological conditions on all continents. The analyses confirmed the assumption that good risk management in general helps to reduce damage.
However, it is particularly difficult to reduce the impact of extreme events whose magnitude has not been seen in the past in the affected area. Anne van Loon explains this on the basis of two factors. First, infrastructures such as dams and reservoirs have an upper limit in design to where they are effective. Once a threshold is exceeded, they become ineffective. Second, risk management is usually introduced or adapted reactively after major floods and droughts, while proactive, anticipatory strategies are rare.
Three success factors
The researchers also examined two success stories, in which the damage was less despite a higher hazard in the second event. They identified three success factors: effective governance of risk and emergency management, high investment in structural and non-structural measures, and improved early warning and real-time control systems. Marleen de Ruiter says: "We believe that applying these success factors can counteract the current trend of increasing damage from extreme events under climate change conditions."