802. Increasing Risk of Flash Drought

According to United Nations world population projections, the world's population is expected to reach 9.7 billion by 2050, making the stability of food production a challenge for food security.

Meanwhile, as climate change increases the frequency of extreme weather events, there are concerns about the impact of extreme droughts and floods on food systems and agricultural productivity.

Many people are probably familiar with the term flash floods, which occur rapidly after heavy rains, as an example of extreme weather events. Droughts, on the other hand, typically occur over several years or decades, but in recent years there has been an increase in flash droughts, droughts that rapidly increase in intensity over a period of weeks or months. The rapid loss of soil moisture due to rapid evapotranspiration is often accompanied by significant economic damage in societies that cannot afford to take adequate countermeasures, although not only crops but also grasslands for livestock grazing are severely affected.

A recent paper published in Communications Earth & Environment predicts that global warming will increase the frequency of flash droughts accompanied by rapid drying, with significant impacts on agriculture and food systems.

An example of a flash drought is the drought observed in western Russia in the summer of 2010, when rapid drying of the land surface caused a heat wave with human casualties and air pollution from wildfires. The drought coincided with the winter/spring wheat planting season and reportedly caused yield losses of up to 70% in Russia's major wheat-producing provinces, leading to government export restrictions in August 2010 and higher global wheat prices.

The authors found that the risk of flash droughts is expected to increase globally under all climate change scenarios, and particularly under extreme emissions scenarios of increased fossil fuel use, with increased risk in North America (32% to 49%) and Europe (32% to 53%), among other regions, between 2015 and 2100. The authors noted that the risk is expected to increase globally.

The authors also presented projections that emissions reductions would significantly reduce the risk of flash droughts in cropland and emphasized the urgency of climate change action.

In fact, Europe, which last year experienced a heat wave and drought that may or may not occur every few hundred years, is already reporting and predicting another drought this year, and some are discussing the alarming possibility that drought is on the verge of becoming the next pandemic.

Reference
Christian, J.I., Martin, E.R., Basara, J.B. et al. Global projections of flash drought show increased risk in a warming climate. Commun Earth Environ 4, 165 (2023). https://doi.org/10.1038/s43247-023-00826-1

Contributor: IIYAMA Miyuki (Information Program)