recovery from a shock becomes much longer (extended by three years under realistic assumptions), especially under limited reconstruction investments. Top-down, long-term models, as well as exposure and vulnerability-based studies cannot be expected to reproduce the total effects of an extreme event and this would probably apply to coastaldisasters as well. Both approaches under-represent indirect effects (migration and consequent long-run effect on growth, see for example Zissimopoulos and Karoly 2007 15 ), social and institutional aspects (political stability, inequality, education, trade openness, financial development, government burden) and more generally elements that are difficult to translate into monetary values. Cavallo and Noy (2011) show that only disasters followed by political revolution have a persistent (lasting 10 years) effect on economic growth, indicating that the political stability ofa country and institutional conditions certainly influence a country’s vulnerability to disasters.
Morphodynamics is the evolution of the shape ofa system such as river estuary, including the water movement, sediment dynamics and salinity distribution as a function of the driving forces (sealevel, tide, river flow, human interference). Development of morphodynamics modeling has been worldwide raised for representing the response of sediment dynamics to natural driving forces and human intervention. Prediction of morphological changes with numerical models is a powerful technique (van Rijn, 2001). It is nowadays a topic of increasing interest in the fields ofcoastaland estuarine management, environment protection, and water resource exploitation. Operated over timescales of months to decades, the morphodynamics model can provide information on how the morphology of an estuary should evolve in response to natural or man‐made forcing (Lesser et al., 2004; Sutherland et al., 2004a, 2004b). However, the research and development of these models are still in progress and not finished. Morphodynamics modeling often perform poorly in detail due to several reasons. First of all, the longer term morphological changes are driven by shorter term processes such as flow, tidal and sediment motions. Many aspects of the complex interrelation between flow, waves, sediment flux, bottom change, morphological time scales and vice versa are not definitely investigated sophisticated for long term applications. Especially for practical applications, the secure prediction of morphological changes is often required. Second, sediment characterization is very complex due to the presence of both cohesive and noncohesive materials, originating from the river, the sea, and/or from wind transport. The study of sand–mud mixtures is still one of the pioneering areas in sediment transport modeling (Toorman, 2001). Furthermore, the behavior of cohesive sediments is influenced by a large amount of parameters and processes, which are often difficult to describe and that introduce large uncertainties in the morphodynamics model prediction. Over the recent decades, there have been continuing efforts to enhance the understanding of morphodynamics models. State‐of‐the‐art models are becoming increasingly sophisticated in their attempts to model the flow condition and sediment transport accurately (Benkhaldoun et al. 2009).
Coastal areas are of great importance for prosperity and economy of human societies. In EU these areas are inhabited by approximately 200 million people and they should really be protected, in a context of rapid globalization andclimatechange. In 2007, EU proposed and developed the Floods Directive 2007/60/EC (FD) in order to reduce and manage the risk of flooding affecting environment and human societies and activities. This stresses the importance of the assessment ofcoastal vulnerability to flooding. Vulnerability, according to the recommendation of the FLOODsite project, is the potential ofa system to be harmed by a hazard (Gouldby and Samuels, 2007). However, the complexity of the morphology and dynamics of the coastal areas makes it very difficult to adopt a common methodology, for the evaluation of vulnerability to flooding. The IPCC's Common Methodology was the first method to be widely applied to assess the vulnerability of countries to sea-levelrise (IPCC, 1992). However, the methodology lacks the flexibility to consider factors of critical significance. In 1991, Gornitz et al. developed and proposed the Coastal Vulnerability Index (CVI) which was widely applied at USA and Canada coastlines. A more complex index, Coastal Social Vulnerability Index (CSoVI) was proposed by Cutter et al.(2003) which combines CVI and some socio-economic parameters. The CSoVI is a combination of variables for North America and Australia coastal regions. Another effort for the assessment ofcoastal vulnerability was pro-
The Links between ClimateChange, Disasters, Migration, and Social Resilience in Asia | 9
expected to place considerable pressure on rural livelihoods, a dynamic sometimes described as “double exposure” (O’Brien and Leichenko 2000).
Scale ofclimate-induced migration. The estimates ofclimate-related migration in Asia are diverse, with one study projecting up to 60 million migrants in South Asia alone by 2050 (Rigaud et al. 2018). The spatial distribution of these migrants is uneven across the region. Since climate-related out-migrations occur in areas of deteriorating water availability and crop productivity, hotspots include the northern part of the Gangetic Plain and parts of the broader Gangetic Plain and the Delhi–Lahore corridor. Sealevelriseand storm surge impacts will dampen growth in major coastal metropolitan areas such as Chennai, Chittagong, Dhaka, and Mumbai. For example, Mumbai, a low-lying city vulnerable to cyclones and severe ﬂooding, may become less hospitable, especially under a high- emissions pathway, which projects asealevelriseof 2 meters by 2050. However, declining crop productivity raises the high likelihood of movement toward sources of income that are not dependent on climate in cities such as Hyderabad and Karachi, amplifying already existing patterns of rural–urban migration. Climate impacts are also especially dire for low-lying deltaic countries, such as Bangladesh, where the same study projects 13 million internal climate migrants by 2050 (Rigaud et al. 2018).
Globally, the single-most observable, predictable, and certain impact ofclimatechange 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 ofsea-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 ofcoastal 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 ofsea-levelrise as they do not incorporate these risks in their investment decisions.
Furthermore infrastructure like e.g. roads, railways or transmission links of energy be- tween the safe havens would be more vulnerable against the impact of storm surges and would require much higher maintenance costs than in protected areas. Already a rough comparison makes it evident that Accommodation as an alternative coastal protection strategy for dealing with an accelerating sea-levelrise will require high investments corre- sponding with enormous economic losses due to the abandonment of smaller settlements and agricultural revenues on the one hand and increasing maintenance costs of infrastruc- ture after flooding due to storm surges. For areas like the lowlands at the Lower Saxon coast the strategy Accommodation is therefore extremely unfavourable in comparison to protection of the areas in total.
This will impact on the airports’ transportation activities for flights (3.1%), passengers (3.5%), freight and mail (9.9%). However, the detrimental consequences do not stop here, because airports located in a today 2 meters altitude are also concerned because of the change in the intensity in storms and floods that largely remain unknown. Thus, the 2°C assumption does not remove uncertainties about the effective consequence of the SLR. Hope and Pearce (2014) recall how Nordhaus in 1975 defined this value, and how it became the actual indisputable benchmark for policy makers. Reaching this point, we must distinguish two things. The first one is the relationship between the 2°C benchmark and the well accepted idea ofariseofsealevel limited to one meter in the worst IPCC’s scenario. The second one concerns threatened Countries by the ocean rise that reject this temperature as detrimental for them and Petra Tschakert (2015) shows that it is highly controversial: “Among parties to the United Nations Framework Convention on ClimateChange (UNFCCC), many Caribbean states proclaimed already at COP15 that a 2°C temperature rise was unacceptable as a safe threshold for the protection of small island states and that even a 1.5°C increase would undermine the survival of their communities”. Tschakert (2015, p.2).
Abstract: Climatechange is a natural phenomenon which accelerates due to human activities. This would result in altering the natural processes on the Earth. The climatechange impacts on the sea environment have adverse effects on the coastal infrastructures. There will be large variation in temperature, humidity, water density, wave and current parameters due to sealevelriseand, which all together affect the structures. It accelerates the rate of deterioration of the structure in the form of corrosion, sulphate attack, erosion and scouring at the foundation due to waves, current, etc. In this paper, a berthing structure in a port located along the west coast of India is considered for the study. The berthing structure was severely damaged due to the exposure to the aggressive sea environment. Visual inspection and non-destructive tests like UPV, Half-cell potential, powder sampling, core sampling were conducted to assess the damage occurred to the structure and retrofitting methodology is proposed in order to prolong the life of the structure.
Abstract — Climatechangeand the resulting sealevelrise are a serious threat to coastal zone in the world, including estuaries andcoastal villages. The consequence ofsealevelrise (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.
In addition to varying the parameters µ and ω as dis- cussed in the main text, the alteration of the scale pa- rameter σ represents also a potential impact from climatechange. Such an effect could be explained by changing wind patterns leading to a lower or higher variability of water levels. Although alterations of σ can be observed (Mudersbach and Jensen, 2010), the underlying mechanism behind is still unexplained. Nevertheless, for the sake of com- pleteness, we investigate the hypothetical effect ofa varying scale parameter σ on the annual damage – analogous to the other parameter shifts. The corresponding asymptotic rela- tions, Eqs. (B14) and (B15), are derived in the following sec- tion. Figure A1 illustrates the comparison of numerical cal- culations with the asymptotic results. It can be seen that in both case studies the increase of damage is less steep than the asymptotic behaviours for σ close to the present value
Decision-making in the coastal zone is a complex issue. Many agencies are involved and even if acoastal zone management (CZM) scheme is in place, meaningful co-operation is not guaranteed. Chapter 3 discusses coastal zone management (CZM) in China and highlights the structural impacts the Chinese political system has on the decision-making processes involved. In order to describe the political conditions found in the country, general power structures are distinguished between the formal (the political system and the administrative set-up) and the informal (the personal networks of the guanxi-system). In this way, the polity of China is evaluated as an obstacle to the adoption of general CZM guidelines that are tailored for systems that are more democratic. In order to examine the potential of bottom-up, instead of top-down, approaches, two local CZM programs in the city of Xiamen and the municipality of Shanghai are compared. The very successful integrated CZM project of Xiamen is applied, in theory, to Shanghai. This device reveals that applicability not only depends on the organizational set-up of the CZM program (naming a responsible agency, allocating participating sectors, formulating goals and policies, identifying instruments, building a legislation, broad participation) but also on factors such as political will (of the responsible agency), a clear jurisdiction of responsibilities (of involved government agencies) and the acknowledgement of informal structures, such as the guanxi. An organizational set-up for CZM in China that includes informal power structures is proposed. A transparent jurisdiction and political system are necessary for a functioning legislation in a country like China, where classical stakeholder participation is less decisive and, therefore, power structures among agencies and the ability to cooperate gain in importance. Informal power structures are often underestimated or completely excluded from analysis, as they are difficult to measure, however, they should not be ignored. For example, the guanxi determine almost all spheres of life and activity in China.
ABSTRACT: In the present work a Boussinesq type hydrodynamic and morphodynamic model is applied to simulate cross-shore coastal erosion during a storm surge event under extreme wave conditions. Non linear wave transformation in the surf and swash zone is computed by a non-linear breaking wave model based on the higher order Boussinesq equations for breaking and non breaking waves. The new transport rate formula (involving unsteady aspects of the sand transport phenomenon) is adopted for estimating the sheet flow sediment transport rates, as well as the bed load and suspended load over ripples. Suspended sediment transport rate is incorporated by solving the depth-integrated transport equation for suspended sediment. The model is applied to determine extreme beach erosion andcoastal flooding due to storms in Eressos beach (Lesbos island, Greece). Extreme values of wave height and period as well as sealevelrise are estimated using extreme value theory techniques. Marginal Extreme Generalized Value (GEV) distributions are first fitted to wave height and storm surge extremes. The dependence structure between wave height and storm surge extremes is modeled using a distribution from the family of Multivariate Ex- treme Value distributions (MVE), namely the simple bivariate logistic distribution function.
The costs ofcoastal sector impacts from sealevelrise (SLR) are an important component of the total projected economic damages ofclimatechange, a major input to decision-making and design ofclimate policy. Moreover, the ultimate costs to coastal resources will depend strongly on adaptation, society’s response to cope with the impacts. This paper presents a new model to assess coastal impacts from SLR, combining global scope with high spatial resolution to fill a gap between very detailed local studies and aggregate global estimates. The Coastal Impact and Adaptation Model (CIAM) determines the optimal strategy for adaptation at the local level, evaluating over 12,000 coastal segments, as described in the DIVA database (Vafeidis et al, 2006), based on their socioeconomic characteristics and the potential impacts of relative sealevelriseand uncertain storm surge. An application of CIAM is then presented to demonstrate the model’s ability to assess local impacts and direct costs, choose the least-cost adaptation, and estimate global net damages for several probabilistic SLR scenarios (Kopp et al, 2014). CIAM finds that there is large potential for coastal adaptation to reduce the expected impacts of SLR compared to the alternative of no adaptation, lowering global net present costs by a factor of 10 to less than $1.5 trillion over the next two centuries, although this does not include initial transition costs to overcome an under-adapted current state. In addition to producing aggregate estimates, CIAM results can also be interpreted at the local level, where we find that retreat (e.g., relocate inland) is often a more cost-effective adaptation strategy than protect (e.g., construct physical defenses).
The effect ofsealevelrise is an equally important effect ofclimatechange on the potential damage that may result from cyclones. Higher sealevel provides storm surges with a higher ‘launch point’ for the surge, which may increase both the real extent and the depth of the surge in areas already vulnerable to coastal storms. In addition, future sealevelrise, while uncertain, is a more reliably forecast to 2050 than future storm activity. In general, the increase in sealevel would make existing storms significantly more damaging, even for minimal changes in storm activity. This analysis focuses on the more reliably forecast marginal effect of SLR on the extent and effective return period of these already damaging storms. Using a simulated dataset for storms and surges along with three alternative forecasts for future SLR in Vietnam, we estimate the effect ofclimatechange induced SLR on surge risk due to cyclones. The overall method involves four steps:
The concern about SLR for these regions is the potential for SLR to affect economies and populations in dramatic ways. Industries that operate in low-lying coastal areas, including tourism, settlement, shipping, commercial and recreational fishing, and agriculture face pressures and consequences from SLR (Neumann et al. 2000). Additionally, road infrastructure is an important component when considering the impacts of SLR. Because infrastructure investment represents an important aspect of national budgets and economic development, and the life cycle of many roads is 20 years or greater, it is important to consider climatechange for current and future plans. For low-lying coastal areas, specifically those in developing countries, making decisions about infrastructure with a forward-looking perspective is a key to mitigating potentially costly impacts from SLR.
One interesting feature is the temperature distribution in the tails. The 99 th percentile ranges from 5.6 (WITCH) to 7.1 °C (MERGE), while the far tail of the 99.9th percentile ranges from 6.2 (WITCH) to 8.5 °C (MERGE).
Table 5 shows the distribution of the SCC for the three models that provide these estimates. These are the estimates of the present value of the flow of future marginal damages of emissions in 2020. Two of the models (WITCH and DICE) use similar quadratic damage functions and are roughly comparable in the middle of the distribution, but the range is much smaller in WITCH. 6 The FUND model has much lower damages (due to a different damage function), and the SCC distribution is an order of magnitude lower than the other two models. Note that the central estimate of the SCC here is $13.30 per ton of CO 2 . This is much lower than the preferred estimate of the US government for 2020, which is $46 per ton in 2011$ with a 3% annual discount rate. However, the base case discount rates in the MUP runs for the models that report average 4½% per year to 2050. The IAWG estimate at a 5% discount rate is $13 per ton and therefore consistent with the estimates presented here.
A fifth interesting finding of this analysis is the lack of evidence in support of fat tails in the distributions of emissions, global mean surface temperature, or damages. Population growth, total factor productivity growth, andclimate sensitivity are very likely to be three of the key uncertain parameters in climatechange. Yet, based on both informal and formal tests, the models as currently constructed find that the tails are relatively thin. The decline in probabilities associated with achange in any of the variables is much larger than would be associated with an infinite-variance Pareto process. As discussed above, we emphasize that these findings should be interpreted in the context of the current group of models and the assumed pdfs. The results do not rule out fat tails, but they do provide empirical evidence against fat tails in outcomes investigated in this study for the current set of models and the distributions of the three uncertain variables considered here. These results tend to support the use of expected benefit-cost analysis for climatechange policy, in contrast to suggestions by some authors that neglect of fat tail events may vitiate standard analyses (Weitzman 2009).
Another point of criticism concerns the heterogeneity of sector analyses. The depth of analysis between the sector studies differs substantially. For example, the infrastructure study and the analysis of investment needs in agriculture, forestry and fisheries adopt a simple mark-up methodology. In contrast, the coastal-systems study employs detailed physical-impact modelling together with cost-benefit analysis. Aggregating the sector estimates hides those differences. 4 Agrawala et al. (2008) note that a particular distortion might be introduced by the infrastructure estimate which represents up to three quarters of the total estimate and therefore has a large influence on the aggregate result. They also highlight the risk of double-counting investments, since infrastructure is also the main component of the coastaland water sectors, among others, including coastal defences and flood protection, but also infrastructure used for heating and cooling purposes and for hydropower production (UNFCCC, 2007). The infrastructure estimate is obtained by applying a simple mark-up methodology similar to the studies by Simms et al. (2004), the World Bank (2006), and the Stern Review (2007) which were discussed above. Two differences are that total infrastructure investment is projected forward to the year 2030 and that the portion ofclimate-sensitive infrastructure investments is estimated based on insurance data. However, the UNFCCC (2007) study applies the same uniform mark-up (5-20%) to estimate the additional costs ofclimate proofing sensitive infrastructure as the Stern Review (2007) applies for developing countries. Thus, this methodology is subject to the general criticism of first-generation adaptation- cost estimates raised above and stressed in a detailed reviewof the UNFCCC infrastructure estimate by Satterthwaite and Dodman (2009).
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-levelriseand 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 ofcoastal infrastructures in order to avoid any misdesigning of seaports or even to maladaptation practices in remote islands.