Assessing the impact of extreme climate events on European gross primary production

Climate warming and the associated intensification of extreme climate events (such as droughts, heavy precipitation, and heatwaves) present challenges to plant growth. Plant growth is influenced by a number of factors such as soil moisture, water demand by plants, temperature sensitivity, growth stage, and by irrigation practices in the case of crops. The response of plant growth to extreme climate events across a range of growing periods, climate regions, and agricultural land types under different irrigation strategies remains unclear. This study utilizes ten extreme climate indices and six drought indices to predict plant growth outcomes, as indicated by the end-of-growing season Gross Primary Production (GPP), across different growing seasons in Europe from 2003 to 2020. This work examines the impact of extreme climate events on plant growth with a novel explainable LightGBM model. This model elucidates the contribution of such events to plant growth, and helps to identify their tipping points. This paper's results demonstrate that early-season soil moisture and extreme absolute temperatures are key predictors in forecasting the end-of-growing season GPP, indicating potential drought memory. Plant growth correlates highly with extreme climate events in arid, cold, and temperate climates. In arid climates the extreme precipitation amounts are the predominant predictor of end-of-growing season GPP. Agricultural drought plays a leading role in the model prediction results in cold climates. Extreme climate events have a more pronounced effect on plant growth yield in rainfed cropland and grasslands compared to irrigated croplands. The implementation of irrigation strategies involving human intervention would help mitigate the impact of extreme climate events on plant growth outcomes.