Stimulus details: sea-level rise

impact chain for tropical coastal areas / sea-level rise (click nodes to view details):
Sea-level rise (SLR) is one of the most certain outcomes of climate change. Relative SLR that exceeds mangrove sediment accretion and elevation is a substantial cause of recent and predicted reductions in mangrove areas and health, as it leads to sediment erosion, inundation stress and increased salinity at landward zones.[13] Even when mangroves have the possibility of migrating landwards (i. e., no barriers are present), conservation concerns are not eased, because it is the seaward fringes that provide the most valuable ecosystem services for fisheries and coastal protection.[18] Any degradation or loss of mangroves will also result in substantial carbon emissions.

Accelerating SLR can also have an impact on coral reefs through increases in energy and sediment resuspension, and drowning. Sediment particles that settle on coral surfaces interfere with photosynthesis and feeding, and turbidity induced by suspended sediment reduces incident light levels.[19] As mentioned above, coral reef degradation will have detrimental effects on reef fish, and subsequently on the coastal communities that depend on them for their livelihoods. Mangrove ecosystems also provide important habitats for fish and crustaceans and any losses in their extent will increase people's vulnerability. Furthermore, alterations in tidal patterns and increased turbidity and salinity will directly lead to modifications of fish habitats and, in turn, to changes in the distribution of many fish species, especially estuary species.[17]

Following mangrove losses, and hence the protective services they provide, coastal communities will experience the negative impacts of SLR and tropical storms more strongly. The SLR impacts of inundation and shoreline erosion have been exacerbated along many coasts in the Pacific by the clearance of coastal vegetation, the mining of sand and the construction of artificial structures that fail to take into account coastal dynamics.[20]

SLR will have both direct and indirect impacts on coastal settlements and agriculture. Indirect impacts are associated with the loss of ecosystem services caused by the inundation and degradation of ecosystems. Direct impacts are inundation and erosion of land, saline water intrusion and coastal flooding. The losses of land, livelihoods and property caused by SLR are projected to be significant and to force many coastal communities to migrate.[21]

Sea levels will continue to rise even under the strictest mitigation scenarios, and measures should be taken to protect coastal communities and ecosystems. However, ecosystem management should be done at the landscape level to manage sediment and other inputs that can induce further stress on coastal ecosystems. Activities can be conducted within the mangrove catchment to maintain or enhance elevation.[13]


[13]    Gilman, E. L., Ellison, J., Duke, N. C., Field, C., 2008. Threats to mangroves from climate change and adaptation options: a review. Aquatic Botany 89, 237-250.

[17]    Martínez Arroyo, A., Manzanilla Naim, S., Zavala Hidalgo, J., 2011. Vulnerability to climate change of marine and coastal fisheries in México. Atmósfera 24, 103-123.

[18]    López-Medellín, X., Ezcurra, E., Gonzélez-Abraham, C., Hak, J., Santiago, L. S., Sickman, J. O., 2011. Oceanographic anomalies and sea-level rise drive mangroves inland in the Pacific coast of Mexico. Journal of Vegetation Science 22, 143-151.

[19]    Ogston, A. S., Field, M. E., 2010. Predictions of turbidity due to enhanced sediment resuspension resulting from sea-level rise on a fringing coral reef: evidence from Molokai, Hawaii. Journal of Coastal Research 26, 1027-1037.

[20]    Nunn, P. D., Mimura, N., 1997. Vulnerability of South Pacific island nations to sea-level rise. Journal of Coastal Research 133-151.

[21]    Wetzel, F. T., Kissling, W. D., Beissmann, H., Penn, D. J., 2012. Future climate change driven sea-level rise: secondary consequences from human displacement for island biodiversity. Global Change Biology 18, 2707-2719.
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