Sea level rise and coastal erosion

Coastal erosion is a natural process of changing shape over time given the unstable character of this landform, and depends on different factors such as wave action, ocean currents, sediment load and sea level rise (Landry et al, 2003). Sea level rise by global warming has been recognized as one of the biggest threats to beach erosion (EPA, 2008, Zhang et al, 2004). At least 100 million persons live within one meter of mean sea level and are at increased risk in the coming decades. The very existence of some island states and deltaic coasts is threatened by sea level rise (Zhang et al, 2004).

Fig. 1 Sea level rise scenarios for two small islands

Opinions are diverse regarding sea level rise and the model applied to calculate it, varying from 0.30 m to 2 m by the end of the century (fig 1.)

Most of these differences depend on including or not the melting of glaciers and ice loss to the sea, but they all agree on important consequences of this rise in the oceans (Rahmstorf, 2007 , Meier et al, 2007,Meehl et al, 2005, Overpeck et al, 2006).

When we talk about the need of planning for the future, coastal erosion caused by sea level rise should be one good example, but to date, there are no appropriate measures to face a problem that will increase at the same pace as global temperatures in the near future. Just to mention at which point we are behind with proposals and solutions, the population of Kiribati in the southern Pacific and The Maldivas in the Indian Ocean, are facing the disappearance of their homeland by sea level rise in what has been called, the first climate change force displacement.

The truth is that we cannot avoid what is already happening, the question is, how are we going to react and how fast? Experts propose different ways to manage coastal erosion, from different types of beach nourishment to shoreline retreat, which is basically, letting nature act and move back, (Landry et al 2003) but some areas do not have enough space to move back as the abovementioned case of small islands or there might be other constraints. It is also important to notice that some of the most expensive properties and developments are exposed to coastal erosion as well as poor communities, mostly in developing countries. The measures to manage this problem must guarantee equality for not only the valuable real estate be protected, but all human settlements as well.

An Strategic Environmental Assessment (SEA) at a governmental level that applies to all threatened coastal areas and flooding risk zones would help to find more appropriate ways to deal with the ocean without leaving vulnerable groups outside and without the fight for private versus public lands.  These measures should all be done fast as the coastlines are slowly being taken by the sea.

Another interesting video from UN


Environmental Protection Agency, 2008. Scientific American online publication

Landry, C., Keeler, A. and Kriesel, W. 2003. An economic evaluation of beach erosion management alternatives. Marine Resource Economics, Volume 18, pp. 105–127

Meehl, G., Washington, W., Collins, W., Arblaster, J., Hu, A., Buja, L., Strand, W. and Teng, H. 2005. How Much More Global Warming and Sea Level Rise? Science 307, pp. 1769-1772

Meier, M., Dyurgerov, M., Rick, U., O’Neel, S., Pfeffer, T., Anderson, R., Anderson, S. and Glazovsky, A. 2007. Glaciers Dominate Eustatic Sea-Level Rise in the 21st Century. Science 317, 1064-1067

Overpeck, J.; Bliesner, O., Bette, L., Gifford, M., Muhs, D., Richard A.; and Kiehl, J. 2006. “Paleoclimatic Evidence for Future Ice-Sheet Instability and Rapid Sea-Level Rise” USGS Staff — Published Research. Paper 189.

Rahmstorf, S. 2007. A semi-empirical approach to projecting future sea-level rise. Science 315, pp. 368-370

Zhang, K., Douglas, B. and Leatherman, S. 2004. Global warming and coastal erosion. Climatic change 64, pp. 41-58


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