Emerging extreme climate-related stresses over croplands and wheat-harvested areas in the southern Mediterranean region during the 21st century

The frequency and intensity of extreme weather events have noticeably risen in recent decades across the globe, especially over the southern Mediterranean region. This trend poses a threat to plant growth, affecting both the physical and metabolic aspects of plants. With the global necessity to double food production by 2050 to meet growing population demands and changing diets, it becomes crucial to understand further how and when significant changes affecting multiple climate-stress indicators may emerge over croplands and some strategic crops for the southern Mediterranean region, such as wheat.

This paper, therefore, aims to identify the spatial distributions and timings of significant positive and negative climate-related stresses affecting croplands and wheatlands. Using 17 bias-corrected climate models from the Coupled Model Intercomparison Project phase 6 (CMIP6) under the SSP370 scenario, we examine a series of agronomically-relevant climate indicators, characterising the intensity of heatwaves, coldwaves, drought, and heavy rainfall, as well as the frequency of such event to combine at the annual scale and during the reproductive phase of winter wheat. Using observed and projected land-use land-cover scenarios, we then quantify the fraction of croplands and wheat-harvested areas that could potentially be affected by positive and negative changes in these climate-stress indicators.

Overall, our analysis revealed predominantly consistent upward trends in heatwave intensity, maximum drought intensity, and the occurrence of compound Dry and Hot (DH) events expected to emerge in the early future (before 2030). Similarly, the number of Wet and Hot (WH) events exhibits an increasing trend, although not as uniform as the indicators above, and is expected to emerge predominantly in the mid-future (before 2050). Conversely, maximum frost intensity, the number of Wet and Cold (WC) and Dry and Cold (DC) events reveal consistent declining trends over the region emerging mostly in the early future (before 2030).