Tropical groundwater resources resilient to climate change
Tropical groundwater may prove to be a climate-resilient source of freshwater in the tropics as intense rainfall favours the replenishment of these resources, according to a new study published in Environmental Research Letters. As climate observations show that global warming leads to fewer but more intense rainfalls, a clearer understanding of how these sources are replenished is crucial for developing strategies for groundwater usage that are better adapted to the greater variability in rainfall and river discharge brought about by climate change. To examine how these resources are replenished, Professor Richard Taylor (UCL) and Dr Scott Jasechko (University of Calgary) assessed the chemical signatures in precipitation and groundwater at 15 sites across the tropics. By comparing the stable isotopes of oxygen and hydrogen in water molecules from precipitation and groundwater, it was found that groundwater recharge occurs disproportionately from heavy rainfalls. In this instance heavy rainfall was defined as those exceeding the 50th percentile of local rainfall intensity. Professor Richard Taylor (UCL Geography) said: "Our results suggest that the intense rainfall brought about by global warming strongly favours the renewal of groundwater resources. As over half the world's population is predicted to live in the tropics by 2050, dependence on groundwater as a resource will continue to rise.
