Significant Local Sea Level Variations Caused by Continental Hydrology Signals

Space gravity missions have enabled the quantification of the mass component of sea-level rise over the past two decades. Barystatic sea-level rise is predominantly driven by melting polar ice sheets and mountain glaciers. However, continental hydrological processes also contribute to global sea level change at significant magnitudes. We show that for most coastal areas in low-to-mid latitudes, up to half of manometric sea-level rise is due to changes in water storage in ice-free continental regions. At other locations the direct attraction effect of anthropogenic pumping of groundwater over the duration of the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) mission offsets sea-level rise from ice sheet and glacier melt. If these trends in continental hydrological storage were to slow or stop, these regions would experience greatly accelerated sea-level rise, posing a risk to coastal settlements and infrastructure, however, for most coastal communities current rates of sea-level rise would be significantly reduced.