Controlling factors for land productivity under extreme climatic events in continental Europe and the Mediterranean Basin

Within the context of achieving Land Degradation Neutrality by 2030, this work studied to which extent soil variability acts as controlling factor for changes in observed land productivity under extreme climatic events. This was done by analysing 30 years of Normalized Difference Vegetation Index (NDVI) data and coinciding extreme warm, dry and their compound events in continental Europe and the Mediterranean Basin. In order to better understand the response of vegetation activity to extreme climatic events in relation to soil functioning, the data was segmented into different climate zones and further studied as a function of land cover and soil type. This study demonstrated that extreme climatic events cause substantial reductions in the NDVI with the maximum median impact up to 31%, one month after the occurrence of an extreme climatic event. However, the magnitude of NDVI drop largely depended on land cover and soil type. Our analysis showed that for soil types with root depth limitations, lower water retention capacity and the absence of specific symbiotic species in the soil, vegetation activity was more impacted by climate extremes compared to soil types having favourable growing conditions. Natural land cover types, especially taiga and boreal forest, were most sensitive. Consequently, with the expected increase in extreme events, the now stable and productive ecosystems may become unstable and less capable to absorb the CO2 in the future, thereby enhancing climate change and land degradation. Therefore, it is important to have mitigation policies tailored towards maintaining soil functioning in vulnerable ecosystems.