Borehole heat exchangers in coastal areas may reduce heatwave seagrass loss

Abstract Mitigation of climate change, implies, among other measures, the increase on the use of carbon-free energy sources, ensuring a zero environmental footprint. Borehole heat exchangers (BHE), a renewable heat source from the ground used for thermal regulation of infrastructures, could significantly reduce CO 2 emissions. Yet, BHE perturbs groundwater temperature by heating and cooling the ground in summer and winter, respectively, which may alter the temperature of Sea Groundwater Discharges. We propose a methodology to strategically locate BHE to discharge cooler temperatures into the sea during summer, alleviating the extreme marine temperatures occurring during marine heatwaves around the groundwater discharge areas, and ensuring a thermal refuge for temperature-sensitive coastal ecosystems. This study opens a new avenue to accomplish the climate targets of the Paris Agreement and mitigate the negative effects of global warming on coastal ecosystems.