Drought develops slowly and has multifaceted and delayed effects. This makes it difficult to see what the consequences are, compared to extreme weather events, shows a new study. Photo: Mostphotos

The study reports that droughts develop slowly and have delayed and multi-faceted impacts. As such, the full drought phenomenon and its consequences are usually not readily perceived, in contrast to faster developing extreme weather events, like floods or heat waves.

“With the persistent rainfall deficit this summer across large parts of Western Europe, drought has recently become more perceivable. It has already caused serious societal and ecosystem impacts along its development pathways”, says René Orth, group leader at Max-Planck Institute for Biogeochemistry in Jena, Germany, who has conducted the study together with Georgia Destouni, Professor at the Department of Physical Geography, Stockholm University.

The study reveals these typical drought development pathways: rainfall deficits propagate first through soil moisture reductions, then to river runoff depletions, and finally cause impacts on vegetation and crop yields. Deciphering this partitioning of water deficits across different parts of the freshwater system is a crucial step forward in mitigation strategies, as the respective water anomalies threaten different societal sectors and ecosystems.

The researchers suggest that drought response measures need to be tailored based on their new findings on drought development: Early into a drought, response measures should focus on adapting to low(er) stream flows by more efficiently using and storing water.

Further into the drought, the focus should be on irrigation support of essential crops and vegetation, while balancing and temporarily limiting other water uses.

“Such improved drought management might become even more relevant in the future, with possibly increasing drought frequency and magnitude as the climate changes”, says Georgia Destouni, Professor at Stockholm University.

The article “Drought reduces blue-water fluxes more strongly than green-water fluxes in Europe” is published in the scientific journal Nature Communications