A study indicates that Europe and western North America are projected to experience more frequent and severe crop droughts as the planet warms, even in areas with increased annual rainfall. Researchers from the University of Reading investigated how climate change affects soil moisture during crop growing seasons, periods critical for water availability.
Warmer temperatures contribute to soil drying more rapidly than increased rainfall can replenish it, which leads to agricultural droughts. The findings, published in Nature Geoscience, utilized climate data and computer models to identify regions with elevated risk. Identified drought hotspots include western Europe (including the UK), central Europe, western North America, northern South America, and southern Africa.
Professor Emily Black, lead author from the University of Reading, noted that rising air temperatures increase water evaporation from soil and plants. This process contributes to field dryness despite increased rainfall, particularly during spring in Europe and North America. Black suggested that as global temperatures continue to rise, agricultural droughts could become more common in the current century within regions responsible for much of the world's food production. She indicated a need for drought-resistant crops and enhanced water management strategies.
The research differs from previous studies by focusing on soil moisture during specific growing seasons, rather than primarily on precipitation patterns or yearly soil moisture averages. This approach revealed drought risks that annual precipitation measurements may not capture.
Spring soil moisture levels at the beginning of the growing season are a determinant of summer drought risk. Elevated spring temperatures increase evaporation sufficiently to dry out soils, even when spring rainfall increases. This spring drying effect can extend into the summer, making crops vulnerable. Regions like Europe and western North America are anticipated to experience more frequent and severe droughts in the coming decades due to warmer air causing faster soil drying. Past severe European droughts, such as those in 2003, 2010, and 2018, developed following dry conditions in spring or early summer.