Coastal Impacts Due to Sea-Level Rise

Abstract

Recent estimates by Intergovermental Panel on Climate Change (2007) are that global sea level will rise from 0.18 to 0.59 m by the end of this century. Rising sea level not only inundates low-lying coastal regions, but it also contributes to the redistribution of sediment along sandy coasts. Over the long-term, sea-level rise (SLR) causes barrier islands to migrate landward while conserving mass through offshore and onshore sediment transport. Under these conditions, coastal systems adjust to SLR dynamically while maintaining a characteristic geometry that is unique to a particular coast. Coastal marshes are susceptible to accelerated SLR because their vertical accretion rates are limited and they may drown. As marshes convert to open water, tidal exchange through inlets increases, which leads to sand sequestration on tidal deltas and erosion of adjacent barrier shorelines.

A global standard for monitoring coastal wetland vulnerability to accelerated sea-level rise

“…Coastal wetlands provide essential direct livelihood services to millions of people, as well as critical regulating services such as maintenance of water quality, protection from storms and erosion, and carbon sequestration 3,4 . Yet sea-level rise (SLR) threatens human populations around the world and coastal wetlands sensitive to increased inundation 5,6 , making SLR adaptation a top priority for civil society 6,7 . Recent (1993-2009) global mean SLR has been estimated at 3.4 ± 0.4 mm per annum 8 , but it is expected to accelerate significantly over the coming century due to thermal expansion and ice melt 9,10 .…”

“…Contemporary global models suggest that by the 2080s, up to twenty per cent of global coastal wetlands may disappear as a result of SLR alone 11 ; such a loss of coastal wetlands would lead to massive economic and societal costs resulting from increased carbon emissions, the loss of direct and indirect ecosystem services, increased vulnerability to extreme storm events (cyclones, storm surges), and increased costs of adaptation and/or mitigation 12 . A possible 1 m rise in sea level could affect 6.1 million people living on the Nile delta, and a 1.5 m rise could flood 22,000 km 2 of the deltaic areas of Bangladesh, affecting 17 million people 6 .…”

Coastal wetlands of temperate eastern Australia: will Cinderella ever go to the ball?

“…3). If, instead, coastal wetlands can increase the level of their sediments, they can maintain an ecologically sustainable relative position vis-à-vis the increasing level of the sea (FitzGerald et al 2008). There are few reports of changes in surface elevation in Australian coastal wetlands, but Rogers et al (2006) gave rates varying from À0.68 to þ5.27 mm year À1 in various saltmarshes of south-eastern Australia.…”

Sensitivity analysis of climate change impacts on dune erosion: case study for the Dutch Holland coast

“…These numbers are slightly higher than the increase in erosion due to SLR suggested by Li et al (2013) who concluded that erosion volumes will increase by 17 % at Noordwijk with 1.05 m of SLR. In literature (Vellinga and Leatherman 1989;Zhang et al 2004;FitzGerald et al 2008; Nicholls and Cazenave 2010) coastal change with respect to SLR was linked primarily to RD, where RD is defined as the horizontal retreat of the cross-section of the dune under an offshore surge level including SLR in the pre-and post-storm profile. In our simulation, RD is larger for Noordwijk than for Egmond (e.g., RD = 15 m in Egmond and 25 m in Noordwijk for SLR of 1.3 m).…”