Sea Level Rise

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Warmer global temperatures associated with climate change will likely result in Sea-Level Rise (SLR), which is caused by both thermal expansion of sea water and from glaciers and ice sheets melting into the ocean. Current measurements of SLR show an annual increase of 3 mm. The Intergovernmental Panel on Climate Change (IPCC) estimates that sea-level will rise 0.2 m to 0.6 m by 2100. However, SLR could exceed 1 m if there is a catastrophic loss of ice from Greenland or Antarctica.

An increase in sea-level will threaten coastal regions and cause a number of impacts, including lowland inundation, wetland displacement, altered tidal ranges in rivers and bays, changes in sedimentation patterns, severe storm-surge flooding, salt water intrusion into estuaries and freshwater aquifers, and increased wind and rainfall damage in areas vulnerable to tropical storms and cyclones.

Water resource managers located in coastal areas will be most affected by SLR, especially those relying on groundwater for their water supply. This is because groundwater is vulnerable to salt water intrusion and inundation, which increases water salinity. Resource managers relying on fresh surface water located at low elevations and adjacent to the ocean will be vulnerable to salinization. This may necessitate development of new storage techniques and treatment processes.

SLR will also increase storm surges that threaten utility infrastructure and result in greater risk of flooding. This will require water resource managers to make additional investments in protective structures and flood control methods. Infrastructure at the greatest risk from SLR includes water intakes located in estuaries, since sedimentation patterns are dependent on tidal patterns, storm surges, and flow conditions; and buried infrastructure at risk from corrosion due to contact with saltwater. Furthermore, it will be important for water utility managers to include forecasts of SLR into their long-term planning.

Sea-Level Rise – San Francisco, CA Coastal cities, such as San Francisco, are most threatened by sea-level rise (SLR). Over the last century, tidal gauges have shown a 0.6-foot increase in sea level. However, recent observations indicate that the rate of SLR is accelerating, and modeled simulations estimate that SLR could range from 2.3–3.3 feet in 2050 and 1.6–4.6 feet by 2100 (Chung et al. 2009). An increase of this magnitude may result in greater storm surges and salinization of surface and groundwater resources.

Sea-Level Rise – Estonia Overall, the relative impacts of climate change are expected to be mild for Estonia. However, Estonia is vulnerable to sea-level rise resulting from climate change. Though sea-level rise is not forecasted to exceed 1 meter, further increases in sea-levels in Estonia will exacerbate coastal flooding and threaten low-lying coastal infrastructure. These impacts are projected to be particularly large for coastal areas around Tallinn, where infrastructure is often adjacent to the coastline. (European Environmental Agency 2007)

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