DISASTERSIncreasing Impacts of Floods and Droughts Worldwide

Published 14 September 2022

Risk management has reduced the vulnerability to floods and droughts around the world, but their impact is still increasing worldwide.

Risk management has reduced the vulnerability to floods and droughts around the world, but their impact is still increasing worldwide, according to a study published in the journal Nature.

This intensification of the impact of natural phenomena is particularly noticeable when the second event —rain, floods or droughts— affecting the same region has a higher degree of hazard —more intensity and magnitude— than the first previously recorded event.

“This results from the fact that the improvement in management has been based on the parameters of previous episodes, but it has not been designed to cope with such extreme events. The difficulty observed in managing unprecedented events is alarming, especially if we consider that, as a result of the climate change, the hydrological events that are projected are becoming increasingly extreme”, notes Professor María del Carmen Llasat, who received the Saint George’s Cross this year for her scientific career in the field of physics and for the study, research and awareness of climate change and natural hazards.

Llasat is professor of Atmospheric Physics at the Faculty of Physics and member of the Water Research Institute (IdRA) of the University of Barcelona.

Flood and Drought Episodes Worldwide
The study, led by the expert Heidi Kreibich, from the German Research Centre for Geosciences (GFZ), includes the participation of nearly a hundred experts from the International Association of Hydrological Sciences (IAHS).

The study analyses 29 pairs of flood episodes and 15 cases drought episodes in different areas of the world. The aim is to check how these factors involved in risk have changed between the first and the second episode, generally occurring more than ten years apart, but in the same place.

In the case of Catalonia, the study compared pluvial floods in Barcelona that occurred on 21 September 1995 and on 6 September 2018, and the recorded droughts in the periods 1986-1989 and 2004-2008. To carry this comparative analysis out, in the case of the rainfalls, the researchers worked in collaboration with Barcelona Water Cycle (BCASA) —entity in charge of the pluvial rain management in Barcelona—, and regarding the droughts, they worked in collaboration with the Ebro Observatory (URL-CSIC).