Journal Article

Multi‐Indicator Assessment to Assess the Increasing Impacts of Compound Dry and Hot Events on Global Wheat Yield

Skalsky, Rastislav, Folberth, Christian, Zhang, Gangfeng, Shi, Peijun, Hu, Jinpeng

2026

Overview

In a warming climate, the co‐occurrence of drought and heat events increasingly threatens the global wheat yield and food security. However, changes in compound dry and hot events (CDHEs) during the global wheat growing season and their impacts on yield remain largely unknown. Using daily ERA5 reanalysis data, multiple drought indicators including the standardized precipitation index, standardized precipitation evapotranspiration index, standardized soil moisture index (SSI), and heat indicators the standardized temperature index and standardized soil temperature index (SSTI), are compared to assess the evolution of CDHEs and their impacts on wheat yield in major wheat‐producing regions (1981–2020). The results indicate significant increases in the frequency, duration, and intensity of global CDHEs, with the most pronounced increases experienced in arid and semiarid regions (Eastern Europe, Central Asia, and Turkey). SSI–SSTI was most sensitive to frequency changes, SPEI–SSTI best captured intensity and duration, and SPI–STI provided conservative estimates. These trends reflect regional hydrothermal conditions, land–atmosphere interactions, and agricultural management. When CDHEs account for more than 10% of the growing season, over 70% of wheat areas experienced negative yield anomalies with an average anomaly of −6.3%; Canada, Australia, and Central Asia were severely impacted, whereas highly irrigated regions (e.g., China and India) were less impacted. Indicator combinations incorporating evapotranspiration and soil moisture (SPEI–SSTI, SSI–SSTI) were most strongly correlated with yield anomalies, highlighting their effectiveness for compound stress detection. This study emphasizes the importance of multi‐indicator assessments and regional adaptations for developing climate‐resilient agricultural strategies. Plain Language Summary As the climate warms, extreme drought and heat are occurring more often and can overlap during important crop growth stages. When these two stresses occur at the same time, their impact on wheat production can be much more severe than when they occur separately. This study examined how the frequency, intensity, and duration of such combined events, known as compound dry and hot events, changed globally during the wheat growing season from 1981 to 2020, and how they influenced wheat yields. Multiple approaches, including methods that capture both meteorological and soil conditions, were used to evaluate drought and heat conditions. The results indicate that these compound events are becoming more common and intense, especially in drier regions such as Eastern Europe, Central Asia, and parts of Australia. When these events affected more than 10% of the growing season, over 70% of global wheat‐growing areas experienced negative yield anomalies, with an average reduction of 6.3%. In contrast, areas with widespread irrigation, such as China and India, were less affected. These findings reveal that combining different measurement approaches improves the ability to detect crop stress and underscore the need for region‐specific adaptation strategies to safeguard food production under increasing climate extremes. Key Points Multi‐indicator assessment shows rising compound dry and hot event (CDHE) frequency, duration, and intensity, especially in arid and semiarid wheat‐producing regions Evapotranspiration and soil moisture indicators (SPEI–SSTI, SSI–SSTI) improve detection of CDHE‐related negative yield anomalies in wheat Over 70% of wheat‐growing areas experience negative yield anomalies when CDHEs account for more than 10% of the growing season

• Publisher: John Wiley & Sons, Inc,Wiley
• Subject: agricultural climate risk / Agricultural management / Agricultural production / Anomalies / Climate / Climate change / compound dry and hot events (CDHEs) / Crop yield / Datasets / Drought / Evapotranspiration / Evapotranspiration-precipitation relationships / Food security / Global warming / Growing season / Heat / Moisture index / multi‐indicator quantitative assessment / Physiology / Precipitation / Regional analysis / Regional development / Regions / Remote sensing / Semi arid areas / Semiarid zones / Soil moisture / Soil temperature / Soil-structure interaction / spatiotemporal variability / Standardized precipitation index / Systems stability / Temperature index / Trends / Wheat / Wheat yield / wheat yield anomaly