Abstract. In contrast to recent advances in projecting sea levels, estimations about the economic impact of sealevelrise are vague. Nonetheless, they are of great importance for policy making with regard to adaptation and greenhouse-gas mitigation. Since the damage is mainly caused by extreme events, we propose a stochastic framework to estimate the monetary losses from coastal floods in a confined region. For this purpose, we follow a Peak-over-Threshold approach em- ploying a Poisson point process and the Generalised Pareto Distribution. By considering the effect of sealevelrise as well as potential adaptation scenarios on the involved param- eters, we are able to study the development of the annual damage. An application to the city of Copenhagen shows that a doubling of losses can be expected from a mean sealevel increase of only 11 cm. In general, we find that for varying parameters the expected losses can be well approximated by one of three analytical expressions depending on the extreme value parameters. These findings reveal the complex inter- play of the involved parameters and allow conclusions of fun- damental relevance. For instance, we show that the damage typically increases faster than the sealevelrise itself. This in turn can be of great importance for the assessment of sealevelrise impacts on the global scale. Our results are accom- panied by an assessment of uncertainty, which reflects the stochastic nature of extreme events. While the absolute value of uncertainty about the flood damage increases with rising mean sea levels, we find that it decreases in relation to the expected damage.
3.1 Do SLR’s scientists offer enough certainties to decision-takers? Let us consider an airport’s governance particularly aware about SLR. It intends planning future mitigating investments for the long term. For instance, airport may be located on the Mediterranean coast for near seashore airports (Barcelona (1m) or Nice (2-3m) or, still, Roma (Leonardo da Vinci, 3m). Let us assume that the planner prospects for the future forty years (2055). What are the factors he should take into considerations? Can he reasonably rule out the assumption of finding another location for a new airport? An appropriate answer to this question needs having a clear understanding of the SLR consequences. Indeed, the decision-maker faces several unknown data. Mainly, the analysis defines three scenarios. The first one corresponds to IPCC’s view that considers that the SLR does not exceed one meter during the 21 st century. The second one comes from scientists that raise doubts about it. This need considering then the three following points: i) The relevancy of the 2°C assumption, ii) Sea-levelrise and past warm periods and, iii) The relevancy of semi-empirical models that deal with SLR.
4 Study results
The study results presented here are based on a one-metre SLR, which is the basis of the inundation data adopted for the study. A sealevelrise of one metre will affect the existing estimated road infrastructure in Vietnam to the extent of 19,000 km of road infrastructure inundated and destroyed; just under 12 per cent of existing road infrastructure. This is a cost of approximately US$2.09 billion to replace the inundated infrastructure (Table 3). This is for all road types. The projected SLR is distributed unevenly, with the majority of damage affecting coastal regions in the southern part of the country. There are several provinces where a complete inundation is projected, resulting in a loss of at or near 100 per cent. These include Bac Lieu, Hau Giang, Soc Trang, Tra Vinh and Ca Mau. The ten most affected provinces are located in the Mekong River Delta region and have an average of 77 per cent of road infrastructure destroyed— a total of nearly 15,200 km. Figures 1-3 illustrate the percentage of road infrastructure damaged and total cost estimates at both regional and provincial levels. A full table of approximated damages can be seen in Appendix A.
Finally, there are a host of dimensions to explore in future work. To begin with, key issues that have been omitted from this analysis include the special treatment of vulnerable areas such as low-lying islands and ports. In addition, this type of disaggregated coastal impact model could be extended to account for localized impacts like erosion, salt water intrusion on water resources, coastal tourism and recreation, and interactions with agricultural production. The treatment of uncertain extreme surge and the resulting damages could benefit from exploring different attitudes towards risk, as well sensitivity analysis around the potential for nonstationarity in the storm surge distribution, should warming increase the likelihood of sealevel extremes as in Grinsted et al (2013). Furthermore, CIAM considers storm surge in isolation, however natural disasters often combine flooding with wind damage (e.g., Superstorm Sandy in 2012). This work has begun to examine the potential for suboptimal outcomes, however there are deeper dimensions related to insurance markets and maladaptation that merit treatment. Lastly, future studies could extend the direct cost estimates presented here, integrating the high resolution of CIAM’s adaptation decisions with a CGE framework to determine the economy-wide welfare effects of sealevelrise.
Figure 2: Maximum flood current velocity in the reference case (Ref) (a), changes due to sea-levelrise (SLR - Ref) (b), changes due to sea-levelrise and topographic changes ([SLR & TC] – Ref) (c) and residual changes due to topographic changes ([SLR & TC] – SLR) (d). The same for maximum ebb current velocity (e-h) and the ratio of maximum flood current velocity to maximum ebb current velocity (i-l). Depth contour lines are displayed for 0, 3, 10 and 30 m below NHN.
ABSTRACT: The Elbe, Jade-Weser, and Ems estuaries located in the German Bight (North Sea) are not only important ecosystems, they are also used as waterways. The hydrodynamic conditions in these estu- aries are influenced by several factors. One of them is the sealevel in the North Sea. Future climate change leads to an accelerated increase of mean sealevel in the North Sea. We need to know how this af- fects the hydrodynamic conditions in order to develop adaptation strategies. The objective of this work is to investigate how sealevelrise changes tidal dynamics in the interior of the estuaries. Using 3D- hydrodynamic numerical models we simulate estuarine hydrodynamic conditions. We carry out different model simulations with and without sealevelrise. The analyses show that in most parts of the estuaries high water levels rise more than low water levels. Hence tidal range is larger in the model simulations that include sealevelrise. As a result of sealevelrise the shape of the tidal curve is changed. In many parts of the estuaries flood current velocities increase more strongly than ebb current velocities. Due to the larger ratio of flood current velocity to ebb current velocity upstream sediment transport increases.
Tidal flats of the Wadden Sea (German Bight) play a significant role for coastal defense and maintenance of navigational channels as they dissipate tidal and wave energy in the foreshore area. In principle tidal flats of the Wadden Sea are capable to adapt to sea-levelrise (SLR) by growth due to a more flood dominant tidal asymmetry with increased sediment import in tidal basins and internal redistribution of sediment between morphologic elements of tidal basins (see sketch below). However, estimates of tidal flat growth and associated critical SLR rates vary largely and have been proposed only for single tidal basins so far (e.g. van Goor et al. 2003, Dissanayake et al. 2012, Becherer et al. 2015). This study investigates feedbacks of hypothetic SLR-induced morphological changes of the entire Wadden Sea on tidal dynamics and whether these changes reinforce or compensate hydrodynamic effects, which arise from SLR alone.
Prediction of characteristics of tide in gulfs, estuaries and bays is one of the most important studies for any kind of engineering developments. The long term natural process like sealevelrise will influence the tidal characteristics and the effect will be significant in the semi-enclosed basins, like gulfs and estuaries. Global sealevel change is usually caused by melting of land-based ice and thermal expansion-as water warms. It is estimated that the sea-level for the year 1990-2100 will be rise to 280 to 340 mm (Church & White, 2006). However, as per NOAA data, the global mean sealevel variation is estimated to be order of 3.16±0.4 mm/year. As the global warming based SLR is alarming in ocean waters, it is increasingly im- portant to assess the effect of the same in all the coastal processes. In this study, an attempt is made to un- derstand the effect of SLR on the tidal levels and induced currents, along the Gulf of Khambhat, India. The existing tidal hydrodynamics are also estimated to assess the percentage difference in the levels and currents due to the SLR.
Abstract: The estimation of future sealevelrise (SLR) is a major concern for cities near coastlines and river systems. Despite this, current modelling underestimates the future risks of SLR to property. Direct risks posed to property include inundation, loss of physical property and associated economic and social costs. It is also crucial to consider the risks that emerge from scenarios after SLR. These may produce one-off or periodic events that will inflict physical, economic and social implications, and direct, indirect and consequential losses. Using a case study approach, this paper combines various forms of data to examine the implications of future SLR to further understand the potential risks. The research indicates that the financial implications for local government will be loss of rates associated with total property loss and declines in value. The challenges identified are not specific to this research. Other municipalities worldwide experience similar barriers (i.e., financial implications, coastal planning predicaments, data paucity, knowledge and capacity, and legal and political challenges). This research highlights the need for private and public stakeholders to co-develop and implement strategies to mitigate and adapt property to withstand the future challenges of climate change and SLR.
In line with Gregory et al. (2019), barystatic sealevelrise is understood here as the mass component of the sealevelrise, which is the change in hydrostatic pressure above the deformable ocean bottom. Barystatic sealevel thus reflects the net transfer of water from continental storages as land-ice or groundwater into the oceans. It might be spatially variable due to the effects of gravitational attraction, Earth's rotation, and solid Earth deformation, and can be predicted from numerically solving the SLE (Farrell & Clark, 1976). Barystatic sealevelrise can be also directly inferred from GRACE mass estimates over the oceans. Averaging over huge areas will diminish the contribution of residual ocean tides or circulation signals not accounted for by means of a priori information. Such background models are applied for both tidal and nontidal ocean mass variations during the processing of each gravity field from GRACE sensor data accumulated over one month. Regions in the vicinity of the coasts must not be included into the averaging region since those are expected to be subject of spatial leakage, which would bias the results. Buffer zones are often derived by smoothing a land mask with an isotropic Gaussian filter to exclude all regions with a notable continental influence (Johnson & Chambers, 2013). In the following, we will use five different buffer zones extending between 200 and 1,000 km off the coast.
To quantify its impact on the current status of balance between the Nile and the sea, three scenarios for sealevelrise were analysed using the same model, the scenarios are sealevelrise of 0.24 m, 0.69 m and 1.0 m. The results revealed that the sealevelrise caused more propagation of saline water towards the Nile with values of 1.2 km, 5.1 km, and 6.6 km in case of sealevelrise of 0.24 m, 0.69 m and 1.0 m respectively. To mitigate the sealevelrise impact, discharging more water from Edfina Barrage could be required. The discharge of Edfina barrage will be increased by about 1.15, 3.67 and 5.88 BCM/year, such amount is a considerable loss of the Egyptian water budget (55.5 BCM/year). Some compromises could be done in which more salt water intrusion can be allowed to a certain extent.
2. Church, J.A.; Clark, P.U.; Cazenave, A.; Gregory, J.M.; Jevrejeva, S.A.; Levermann, A.; Merrifield, M.A.; Milne, G.A.; Nerem, R.S.; Nunn, P.D.; et al. SeaLevel Change. In Climate Change 2013: The Physical Science Basis; Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change; Stocker, T.F., Qin, D., Plattner, G.-K., Tignor, M., Allen, S.K., Boschung, J., Nauels, A., Xia, Y., Bex, V., Midgley, P.M., Eds.; Cambridge University Press: Cambridge, UK; New York, NY, USA, 2013. 3. Dasgupta, S.; Meisner, C.; Laplante, B.; Wheeler, D.; Yan, J. The Impact of SeaLevelRise on Developing Countries;
Abstract — Climate change and the resulting sealevelrise are a serious threat to coastal zone in the world, including estuaries and coastal villages. The consequence of sealevelrise (SLR) on the Welsh coast is still ambiguous, and updating of current flood risk tools is necessary to mitigate the potential damages arising from the future flood events along the Welsh coasts. This study focuses on hydrodynamic impacts of SLR on Welsh coasts, particularly in the Dyfi Estuary at Mid Wales, using an advanced modelling tool – TELEMAC2D. The analysis of flood dynamics is based on the time varying water depth and velocity from the model, so that flood index, flood duration and hazard rate can be more accurately predicted and assessed. In this study a high-resolution TEELAC2D model was setup, calibrated and validated for the Dyfi Estuary with a number of SLR and river discharge scenarios. Results showed that with the commonly accepted SLR quantities, a considerable area within the Dyfi Estuary is to be affected, but the flood duration and hazard rate vary widely within the study area, providing the insightful details of the flood risk in the region for better and sustainable future coastal management.
maximum increase in the central section of tidal inlets, e.g. between barrier islands (Fig. 5b ). Some channels also show an increase in maximum ebb current velocity (ve_max) (Fig. 5c ). However, the increase in vf_max is generally larger than the increase in ve_max. Moreover, ve_max decreases in many parts of the tidal channel systems of the Wadden Sea (Fig. 5c ), especially in the landward sections within the tidal basins as well as in some ebb tidal deltas (see the inset of a detailed view in Fig. 5c ). As a result, the tidal channel systems of the Wadden Sea are generally characterised by an increased ratio of maximum flood current velocity to maximum ebb current velocity (vf_max/ve_max) (Fig. 5d ). This implies a reinforcement of flood dominance, an attenuation of ebb dominance, or a reversion from ebb dominance to flood dominance (compare Fig. 4c and Fig. 5e ). Prominent examples for an attenuation of ebb dominance are the ebb tidal deltas of the East Frisian Wadden Sea and the main channel of the outer Weser estuary. Many sections of tidal channel systems, which have no tidal asymmetry of current velocity in the reference case, show distinct flood dominance in response to sealevelrise. These results are in agreement with findings of e.g. Stanev et al. ( 2006 ), French ( 2008 ), and Dissanayake et al. ( 2012 ). However, regional differences are obvious. While an in- creased vf_max/ve_max is observed within the entire tidal chan- nel systems of the East Frisian Wadden Sea and central German Bight, the ratio is increased only in the landward reaches of the tidal channel systems of the North Frisian Wadden Sea. A maximum increase in vf_max/ve_max is often located in the landward sections of the channel systems (see the inset of a detailed view in Fig. 5d ), which is primarily related to a decreased ve_max (see the inset of a detailed view in Fig. 5c ). In response to sealevelrise, the duration of the flood current (df) is shortened in the major tidal channels of the southern German Bight (Fig. 5f ). This is consistent with the observed increase of vf_max/ve_max in these tidal channels (Fig. 5d ).
Globally, the single-most observable, predictable, and certain impact of climate change is sealevelrise. Using a case study from the Kapiti Coast District in New Zealand, we pose a simple question: Do people factor in the warnings provided by scientists and governments about the risk of sea-levelrise when making their investment decisions? We examine the single most important financial decision that most people make – purchasing a home, to see whether prices of coastal property change when more/less information becomes available about property- specific consequences of future sealevelrise. The Kapiti Coast District Council published detailed projected erosion risk maps for the district’s coastline in 2012 and was forced to remove them by the courts in 2014. About 1,800 properties were affected. We estimate the impact of this information on home prices using data from all real estate transactions in the district with a difference-in-differences framework embedded in a hedonic pricing model. We find that the posting of this information had a very small and statistically insignificant impact on house prices, suggesting people do not care much about the long-term risks of sea-levelrise as they do not incorporate these risks in their investment decisions.
The garbage can theory proved to be applicable to new issues – such as climate change – and long-term problems – such as adaptation to sea-levelrise. The analysis in chapter 2 combined the garbage can approach with the three dimensions of a political system – policy, politics and polity – of which the latter has been underestimated in climate change research so far. A straightforward decision based on rational choice is constrained by the relevance these themes have in decision-making of institutions. The analysis equates polity with power structures and it shows that power is decisive in decision-making regardless of the political system. Framework compliance and information control are identified as major factors that are effective in a political system. Polity has been equated with power structures and the analysis showed that power is decisive in decision-making regardless of the political system. Moreover, the benefits of institutional change – in order to meet the demands of new challenges – are questionable as long as only parts of the system (policy, politics and polity) are addressed. Thus, the revised garbage can perspective showed that a global analysis of political and institutional structures is necessary in research into climate change.
ABSTRACT: Sealevelrise (SLR) can give various impacts such as inundation in the low-lying areas, in- crease the coastal erosion and extreme events such as storm surge, wave overtopping, salt intrusion and damage to existing coastal infrastructure, hence affects the socio-economy and the livelihood of the coastal communities. The projected SLR along the Sandakan coast for the year 2020, 2040 and 2060 are 0.1 m, 0.25 m and 0.5 m, respectively. This study was carried out to assess the impacts of SLR to Sanda- kan coast for 2020, 2040 and 2060; and to recommend some relevant adaptation measures to reduce the impact. Hydrodynamic model with simulations of 2020 and 2040 projected SLR show no significant change in Sandakan Town when compared to the existing condition, probably due to its high platform level. However, model simulations for 2060 projected SLR show that the wave heights may increase by 0.18 m compared to the existing 2.6 m, although the wave heights in Teluk Sandakan will not change much. Similarly, the maximum current velocities will increase by 0.15 m/s in 2060, compared to the ex- isting condition of 0.3 - 0.5 m/s. Overall, more impacts of SLR can be observed at Pulau Duyong due to its low-lying area. There will be a reduction in land area; about 958 hectares out of the existing 1,800 hec- tares of mangrove forests and coastal vegetation will be lost due to inundation and erosion, generated by the 0.5 m projected SLR in 2060. Construction of railings, low walls and rock bunds are recommended as an adaptation measures to ensure the safety of the people living along the Sandakan coast. There is also a need to raise the bund and platform levels for jetties and slipways at the Marine Police Complex to avoid inundation. The estimated cost for the recommended adaptation measures is about RM18.25 Million.
remote islands. Air and seaports are important hubs in the exchange of cargo and transfer of passengers in any logistic transport network. Once designed and constructed, seaports interfere with the local hydro- and morphodynamic system and potentially affect adjacent coastal areas. Small reef islands are particularly sensitive towards sea-levelrise and impacts due to coastal structures as implementation may increase their exposure and increase the vulnerability of the local population, if infrastructure development compromise or even imperil the natural equilibrium. This study documents and validates the erosion on the east coast of the Maldivian coral reef island of Fuvahmulah. Two numerical models help to identify the key drivers and interdependent processes of sediment transport on the coral reef and assess the port’s influence in aggravating formerly balanced sediment budgets. Our results highlight the significant susceptibility of reef islands in regard of inherent coastal processes as it calls for thoughtful investigations in the design stage prior to implementation of coastal infrastructures in order to avoid any misdesigning of seaports or even to maladaptation practices in remote islands.
Some limitations faced the work in this research and may affect the results. Data availability in terms of bathymetry data or flow data were in general enough. However, it would be better to have more data for calibration purposes, such as the flow in other locations in the domain not only at the boundaries. No measurements for the salinity in the Nile were found, so it was not possible to calibrate the turbulent diffusivity or to compare the numerical results with data collected from the field. Extending the model by using a wider mesh to include the flood plain, to simulate possible flooding that may occur due to the different sealevelrise scenarios, was not considered in this research. However, the impacts on a wider mesh are expected to be very small.
Global sealevelrise (SLR) variations have undeniably begun to make an impact on highly vulnerable economies. These impacts of SLR are a key component of the projected economic damage of climate change, an important input to climate change policies and adaptive measures. This paper considers SLR projections and its impact on the economy and includes a consolidation of various related studies. Estimated global gross domestic product (GDP) loss by 2100 ranges from 0.3% to as high as of 9.3% (Hinkel et al. 2014; Pycroft, Abrell, and Ciscar 2015). Climate change impact should be addressed at the global level through a locally focused effort where education and acceptance by all stakeholders are crucial and warranted. Further, this paper tackles several adaptive strategies as a response to SLR which include retreat, accommodation, and protection. The retreat strategy simulates that SLR causes the loss of inundated land and incurs planned relocation (migration) costs above a certain sealevel. The accommodation strategy allows usage of vulnerable areas or land and limits damage by flood- proofing or raising structures. Finally, the protection strategy projects that land will be protected from SLR damage by sea walls or other barriers of a certain height. On the other hand, Diaz (2016) estimates a median adaptation cost from migration at 16% of GDP under the least-cost strategy by 2050. In general, the education of and the acceptance by the concerned local community will be crucial in the successful implementation of SLR adaptation strategies, notwithstanding parallel mitigation efforts on a global scale.