Groundwater influence on the frequency of heatwaves: A global perspective

Groundwater plays a crucial role in land-atmosphere interactions through its effect on soil moisture, evaporation and thus surface heat fluxes (1). Variation of rainfall patterns in a changing climate and the increase in water demands are expected to influence groundwater dynamics that affect soil moisture-air temperature feedback processes and subsequently the occurrence of heatwaves. The decline in groundwater levels with intensified abstraction could hinder its buffer capacities to impede soil desiccation and onset of heatwaves. The current understanding of the relationship between shallow groundwater tables and heatwave events is often limited to regional studies or specific land covers, with a very few endeavors seeking to characterize global-scale trends and responses. We thus aim to globally investigate the relation between groundwater levels and heatwave events considering different land cover types and environmental variables by conducting a wide-ranging statistical analysis. Our approach involved leveraging a comprehensive dataset, allowing us to distinguish potential links between groundwater tables and the frequency of heatwaves over a range of geographical and climatological parameters. The findings from our investigation provide valuable insights into the relationship between groundwater dynamics and heatwave frequency within the broader context of the interactions between soil moisture and air temperature. This information will aid in devising effective action plan to mitigate the adverse effects of climate change.     Reference: (1) Maxwell, R., Kollet, S. Interdependence of groundwater dynamics and land-energy feedbacks under climate change. Nature Geosci1, 665–669 (2008). https://doi.org/10.1038/ngeo315