Climate change: Global risk of flash drought projected to increase over cropland

Risk of flash droughts – unusually rapid and severe drying events – over cropland is projected to increase by 2100, especially in North America and Europe, reports a modelling study published in Communications Earth & Environment. Climate model projections suggest that the annual risk of flash droughts over cropland in North America and Europe are set to rise from 32% in 2015 to 49% and 53% by 2100, respectively, under the most extreme greenhouse gas emissions conditions. The increased projected risk to cropland may put food systems under greater pressure.

Flash droughts happen when a lack of rainfall occurs together with high rates of evaporation, causing rapid drying of the land surface. The speed of the development of flash droughts compared to conventional droughts means that there is often insufficient warning to implement mitigation strategies, which can put cropland at risk.

Jordan Christian and colleagues assessed how flash drought occurrence might change and estimated the global risk from flash droughts under different global climate model simulations. The authors analysed historical flash drought simulations (between 1850 and 2014), and projected future flash drought occurrences from 2015 until 2100 under three different ‘Shared Socioeconomic Pathways’ (SSPs) scenarios. These pathways – dubbed SSP126, SSP245, and SSP585 – explore how the world might change under different sets of climate policy and range from a sustainable scenario to a high emissions scenario. Across all three scenarios, the global flash drought occurrence was projected to increase by between 6.0% and 9.5% towards the end of the century.

The authors also found that the flash drought risk is projected to increase for global cropland between 2015 and 2100 compared to the historical period. Under the highest emissions scenario, the annual risk of flash droughts over cropland in Europe increased from 32% in 2015 to 53% in 2100, while in North America it increased from 32% to 49%. Africa, Asia, and South America also saw substantial increases in flash drought risks. The high emissions scenario projects worse outcomes than the two less extreme scenarios.

The authors suggest that as the global population increases, the demand for food and changes in flash droughts may put pressure on food security.