Relative sea-level rise reflects both ocean rise and land motion, which means local flood risk often accelerates when the ground sinks. A key distinction is that subsidence can become the dominant contributor to relative sea-level rise in heavily exploited coastal settings, and exposure can increase far faster in subsiding locations than global mean sea-level change alone suggests. For decision-makers, this framing clarifies why groundwater, drainage, and land-use policy can materially change coastal risk on practical planning timelines (Ingebritsen & Galloway, 2014; Nicholls et al., 2021).
References
- Ingebritsen, S. E., & Galloway, D. L. (2014). Coastal subsidence and relative sea level rise. Environmental Research Letters, 9(9), 091002. doi:10.1088/1748-9326/9/9/091002.
- Nicholls, R. J., Lincke, D., Hinkel, J., Brown, S., Vafeidis, A. T., Meyssignac, B., Hanson, S. E., Merkens, J.-L., & Fang, J. (2021). A global analysis of subsidence, relative sea-level change and coastal flood exposure. Nature Climate Change, 11(4), 338-342. doi:10.1038/s41558-021-00993-z.