Article

A Semi-Empirical Approach to Projecting Future Sea-Level Rise

Potsdam Institute for Climate Impact Research, 14473 Potsdam, Germany.
Science (Impact Factor: 33.61). 02/2007; 315(5810):368-70. DOI: 10.1126/science.1135456
Source: PubMed

ABSTRACT

A semi-empirical relation is presented that connects global sea-level rise to global mean surface temperature. It is proposed
that, for time scales relevant to anthropogenic warming, the rate of sea-level rise is roughly proportional to the magnitude
of warming above the temperatures of the pre–Industrial Age. This holds to good approximation for temperature and sea-level
changes during the 20th century, with a proportionality constant of 3.4 millimeters/year per °C. When applied to future warming
scenarios of the Intergovernmental Panel on Climate Change, this relationship results in a projected sea-level rise in 2100
of 0.5 to 1.4 meters above the 1990 level.

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    • "A good example is Rahmstorf's (2007) work that circumvents the use of complex and incomplete process-based sea-level models by instead finding a historical relationship between temperature and sea-level rise, and applying this to IPCC predictions of future global temperature to derive global sea-level estimates for the year 2100. (In justifying this approach, Rahmstorf (2007) draws an interesting parallel with tidal predictions, which are essentially based on 'experience', because calculations from first principles are too complex and provide results that are less accurate.) Since the work by Rahmstorf (2007), several other semi-empirical studies on future sea-level changes have been published (e.g., Vermeer and Rahmstorf, 2009; Grinsted et al., 2010; Bittermann et al., 2013; see also Church et al., 2013). "
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    ABSTRACT: Future climate change is likely to increase the frequency of coastal storms and floods, with major consequences for coastal transport infrastructure. This paper assesses the extent to which projected sea-level rise is likely to impact upon the functioning of the Dawlish to Teignmouth stretch of the London to Penzance railway line, in England. Using a semi-empirical modelling approach, we identify a relationship between sea-level change and rail incidents over the last 150years and then use model-based sea-level predictions to extrapolate this relationship into the future. We find that days with line restrictions (DLRs) look set to increase by up to 1170%, to as many as 84–120 per year, by 2100 in a high sea-level rise scenario (0.55–0.81m). Increased costs to the railway industry deriving from maintenance and line restrictions will be small (£ millions) in comparison with damage caused by individual extreme events (£10s of millions), while the costs of diversion of the railway are higher still (£100s of millions to billions). Socio-economic costs to the region are likely to be significant although they are more difficult to estimate accurately. Finally, we explain how our methodology is applicable to vulnerable coastal transport infrastructure worldwide.
    Full-text · Article · Feb 2016 · Journal of Transport Geography
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    • "The Intergovernmental Panel on Climate Change (IPCC, 2013) predicted sea-level rise of up to one meter by the end of the 21st century, with a range of uncertainty from 10 to 54 cm. Recent work based on semi-empirical methods suggests that ESLR may be more than one meter (Rahmstorf, 2007; Pfeffer et al., 2008; Mitrovica et al., 2009; Vermeer and Rahmstorf, 2009; Horton et al., 2014; Williams and Ismail, 2015). Increasing eustatic sea-level rise is especially critical in the Mississippi Delta, and other deltas, because it is augmented by high rates of subsidence. "
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    ABSTRACT: The East Joyce Wetlands (EJW) bordering northwest Lake Pontchartrain have a long history of human induced changes, such as leveeing of the Mississippi River that eliminated almost all riverine input to the area and segmentation of the east and west Joyce wetlands by the construction of a railroad, U.S. highway 51, and Interstate 55. Dredged drainage canals and associated spoil banks channel upland runoff around the wetlands. The deep canal associated with I-55 causes both rapid short-circuiting of freshwater runoff to Lake Maurepas and saltwater intrusion from Lake Pontchartrain. Increasing soil salinity has caused wide-spread loss of forested wetlands in the areas. Recently, the discharge of secondarily treated municipal effluent into the northeastern EJW as part of the Hammond wetland assimilation project has focused attention on the area (i.e., Bodker et al., 2015). In response, we carried out a number of studies at the Hammond Assimilation Wetlands (HAW) detailed in Shaffer et al. (2015), as well as a series of hydrological measurements and modeling detailed here. These data show that drainage under the railroad was minimal and most flow through the wetlands was to the southeast. Water levels in the HAW were highly variable prior to the beginning of effluent discharge in 2006, with relatively high mean water levels that did not increase substantially from 2007 through summer 2009 despite the addition of municipal effluent. Following effluent addition, surface water levels lacked the variability of the pre-discharge period and mean water levels were about 20cm higher from late 2009 until 2014 due to high rainfall in 2009, 2012, and 2013 and high effluent inflow due to significant infiltration into the city collection system. Historical net watershed inputs averaged 2.69cmyr-1 if this volume of water were spread over the 4km2 area immediately south of the effluent distribution system, compared to 0.38cmyr-1 for the effluent and 0.13cmyr-1 for direct precipitation. Salinity records from five sites in the EJW showed a gradient of increasing salinity from north to south and strong seasonality, averaging 1.9-2.1 PSU near the lake to 0.4-0.6 PSU in the northwestern EJW. Peak salinities were 4.6-5.1 PSU near the lake and 1.8 PSU in northwestern EJW. There was also a significant decrease in salinity over time. Salinity was lower beginning in 2010 coinciding with the closure of the Mississippi River Gulf Outlet, high precipitation in the fall and winter of 2009, and in 2012 and 2013, and continuing operation of the assimilation system. Proposed plans to alternate effluent discharge between east and west Joyce wetlands should increase surface water depth variability as seen prior to effluent discharge and minimize salinity intrusion in both areas.
    Full-text · Article · Feb 2016
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    • "Global sea level increase in the 20th century measured approximately 170 mm (Bindoff et al. 2007) and is expected to increase exponentially in the 21st century as air temperatures continue to increase (Rahmstorf 2007). By 2050, the sea level is expected to have risen approximately 60–330 mm (Union of Concerned Scientists 2006), and by 2100, is expected to have risen by 50–1400 mm above the 1990 level (Rahmstorf 2007), with the potential to increase > 5000 mm within the next millennium (Overpeck et al. 2006). "
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    ABSTRACT: Lagoons are highly productive coastal features that provide a range of natural services that society values. Their setting within the coastal landscape leaves them especially vulnerable to profound physical, ecological, and associated societal disturbance from global climate change. Expected shifts in physical and ecological characteristics range from changes in flushing regime, freshwater inputs, and water chemistry to complete inundation and loss and the concomitant loss of natural and human communities. Therefore, managing coastal lagoons in the context of global climate change is critical. Although management approaches will vary depending on local conditions and cultural norms, all management scenarios will need to be nimble and to make full use of the spectrum of values through which society views these unique ecosystems. We propose that this spectrum includes pragmatic, scholarly, aesthetic, and tacit categories of value. Pragmatic values such as fishery or tourism revenue are most easily quantified and are therefore more likely to be considered in management strategies. In contrast, tacit values such as a sense of place are more difficult to quantify and therefore more likely to be left out of explicit management justifications. However, tacit values are the most influential to stakeholder involvement because they both derive from and shape individual experiences and beliefs. Tacit values underpin all categories of social values that we describe and can be expected to have a strong influence over human behavior. The articulation and inclusion of the full spectrum of values, especially tacit values, will facilitate and support nimble adaptive management of coastal lagoon ecosystems in the context of global climate change.
    Full-text · Article · Jan 2016
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