Interplay Among Recent Trends in Climate Extremes, Vegetation Phenology, and Crop Production in the Southern Mediterranean Region

Abstract

The southern Mediterranean region is among the most vulnerable areas to climate change globally. However, in this region, there is a need to further understand the complex interactions between climate, vegetation, and crops to fully assess the combined impacts of extreme climate events on the agricultural sector. Using daily Normalised Difference Vegetation Index (NDVI) data, we evaluated trends across 15 vegetation phenology indicators between 1982 and 2019 and analysed their links to land-use land-cover changes. We found significant increases in the maximum value of NDVI (MaxV), length of growing seasons (LengthGS), and duration from crop emergence to anthesis (BMaxT), particularly within croplands. These changes positively correlated with regional crop production, especially in coastal and interior plains where croplands and forests are expanding. Conversely, southern areas bordering the Sahara showed declining MaxV and an expansion of sparsely vegetated areas. We then conducted a comprehensive seasonal trend analysis of climatic stresses and discussed how they align with recent trends in key phenological indicators. Coastal and interior plains experienced wetter conditions throughout the year, ensuring sufficient water during the growing season. Meanwhile, areas bordering the Sahara had wetter autumns and winters but drier springs and summers. Additionally, the region experienced warmer conditions from spring to autumn, with fewer cold wave events. Analysing the frequency and duration of compound extreme events, we observed a trend toward more light to moderate dry/hot days in spring and autumn and light to extreme wet/hot days from summer to autumn. These conditions are significantly correlated with increased MaxV, improved crop productivity, and extended LengthGS and BMaxT. These findings may serve as early indicators of how future climate changes could impact crop production, highlighting regional risks and opportunities to guide informed decision-making and development of adaptive strategies in the southern Mediterranean region.