‘Flash droughts’ will double due to climate change

Sudden droughts that parch soils and dry out plants will double in hotspots in Europe, South America and Africa in the coming decades, a new study has found.

‘Flash droughts’ leave vegetation tinder dry, ruining crops and greatly increasing fire risk. Their impact has been felt in summer 2023, with intensely dry conditions implicated in the devastating fires in Hawaii this summer.

A study published in Advances in Atmospheric Sciences today (31 August 2023) sheds light on the alarming increase in agricultural flash droughts projected over the 21st century. Agricultural flash droughts, characterized by rapid soil moisture dry down, have the potential to wreak havoc on natural ecosystems and crop cultivation. While there are implications for societies worldwide, the study identifies hot spot areas where the risk is projected to worsen the most.

Using output from the Coupled Model Intercomparison Project (CMIP) models, Professor Emily Black, a climate researcher at the University of Reading’s Department of Meteorology, delves into the projected changes in agricultural flash droughts. Her study reveals that these events, which were once considered rare, are anticipated to become more frequent in a warmer future climate, spelling out significant challenges for global societies.

Professor Black said: "Understanding the dynamics of agricultural flash droughts is crucial as these events can have far-reaching consequences on both the environment and food production.

“Our study demonstrates that these devastating phenomena are closely linked to changes in relative humidity, temperature and soil moisture, which are all influenced by the changing climate."

The study's findings highlight that agricultural flash droughts are often preceded by unusually low relative humidity and precipitation. Long-term trends in the frequency of these events are found to be driven by shifts in temperature, relative humidity, and soil moisture levels. Hot spots of increased agricultural flash drought risk have been identified in various regions, including Europe, South America and southern Africa. The implications may be serious, with flash droughts projected to more than double across mid- and high latitudes during the 21st century.

Professor Emily Black is a professor at the University of Reading and a senior scientist at the National Centre for Atmospheric Science, known for her contributions to the field of climate science. Her work focuses on understanding the complex interactions between climate variables and their impacts on ecosystems, with a specific emphasis on drought.