Study reveals rise in occurrence of “Flash Droughts” owed to climate change

Dry spells known as flash droughts, with a surprisingly quick onset and often devastating onset, are becoming more frequent as the planet warms, a study published Thursday shows.

Although droughts are generally seen as a long-term phenomenon, some can occur suddenly, in a matter of weeks, when conditions are right.

Global warming is a recipe for an increase in those special conditions around the world, which in certain regions leads to a decrease in precipitation and an increase in evaporation, which dries up the soil more quickly.

For the study published in the journal SciencesIn this study, the researchers analyzed a set of satellite data and ground moisture readings from a period of more than 60 years (1951-2014).

“Slow, slow droughts are increasing” as global temperatures rise, lead author Xing Yuan told AFP.

But he said rapid droughts are increasing even faster, “particularly over Europe, North and East Asia and the Sahel and West Coast of South America”.

The rapid onset of rapid droughts gives humans little time to adapt, such as diverting water resources or preparing for wildfires, warned the researcher, from China’s Nanjing University of Information Science and Technology (NUIST).

“The vegetation doesn’t have time to adapt either,” he added.

Yuan’s team used climate modeling to predict how sudden droughts might change under several possible greenhouse gas emissions scenarios.

Even if emissions are moderate, rapid droughts will continue to increase in almost all regions. Under higher emissions scenarios, the trend will be steeper.

Yuan also said the data showed a general increase in drought onset speeds, as his team found a “strong shift on a global scale” from slow droughts to more severe droughts.

“We think that reducing emissions can slow this transition,” he told AFP.

The concept of rapid drought appeared in the early 2000s, but it has received more attention since the summer drought of 2012 in the United States, which began especially quickly and caused economic losses of more than $30 billion.

Commentary piece by two professors in the Netherlands, also published in SciencesShe said the study’s warning “must be taken seriously” because the threat “may be greater than it suggests”.

David Walker of Wageningen University and Anne Van Loon of Vrije Universiteit (VU) Amsterdam, both of whom were not involved in Yuan’s work, emphasized that most of the “hot spots” identified by the study were particularly low-income areas.

“These areas generally have more vulnerable populations and fewer financial resources for coping mechanisms,” they said.

The pair also added that existing methods for detecting droughts, which are often monthly data analyses, should be updated to “work on shorter time scales,” given the increase in rapid droughts that “may form and produce results in just a matter of weeks.”

© 2023 AFP