Attributing coastal flood damages to sea level rise for recent flood events

Author(s):  
Simon Treu ◽  
Matthias Mengel ◽  
Katja Frieler

<p>Sea level rise increases extreme water levels and thus the flood losses from storm surge events. While it is still difficult to estimate the influence of climate change on single storms, the influence of anthropogenic climate change on sea level rise is evident. We here aim to quantify the fraction of damages caused by sea level rise for a set of flood events of the last decade. Flood-extents and the spatial distribution of damages are reconstructed from openly available data-sources. We construct counterfactual flood extents for each event by a counterfactual sea level as it would have been in a world without climate change. As we are particularly interested in losses in poorer countries that often lack high resolution data such as LiDAR based elevation maps or tide-gauge records, our methodology is transferable between regions, building on global and open data. Depending on the study site, we detect a difference between observed and counterfactual damages though uncertainties remain high. Data availability and data detail remain a major restriction.</p>

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Naila Matin ◽  
G. M. Jahid Hasan ◽  
Myisha Ahmad

Bangladesh is becoming increasingly vulnerable to the growing threat of climate change induced sea level rise. Considering the potential severe impacts that sea level rise will have on the coastal population and the country’s economy, it has become very important to know about the regional trends of changing sea levels along the coastlands of Bangladesh. The present study attempted to portray a representative scenario of sea level rise in the coastal regions of Bangladesh. Historic tide gauge records, ranging from 20 to 45 years, were used to determine reliable trends at multiple locations along the coast. Linear regression method was applied to derive the changing trend of annual high, mean and low tidal water levels. The location-specific trends of sea level rise determined in this study can be helpful to planners and policy makers to combat the emerging threat of SLR in a more efficient manner.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Benjamin H. Strauss ◽  
Philip M. Orton ◽  
Klaus Bittermann ◽  
Maya K. Buchanan ◽  
Daniel M. Gilford ◽  
...  

AbstractIn 2012, Hurricane Sandy hit the East Coast of the United States, creating widespread coastal flooding and over $60 billion in reported economic damage. The potential influence of climate change on the storm itself has been debated, but sea level rise driven by anthropogenic climate change more clearly contributed to damages. To quantify this effect, here we simulate water levels and damage both as they occurred and as they would have occurred across a range of lower sea levels corresponding to different estimates of attributable sea level rise. We find that approximately $8.1B ($4.7B–$14.0B, 5th–95th percentiles) of Sandy’s damages are attributable to climate-mediated anthropogenic sea level rise, as is extension of the flood area to affect 71 (40–131) thousand additional people. The same general approach demonstrated here may be applied to impact assessments for other past and future coastal storms.


Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 545
Author(s):  
Alexis K. Mills ◽  
Peter Ruggiero ◽  
John P. Bolte ◽  
Katherine A. Serafin ◽  
Eva Lipiec

Coastal communities face heightened risk to coastal flooding and erosion hazards due to sea-level rise, changing storminess patterns, and evolving human development pressures. Incorporating uncertainty associated with both climate change and the range of possible adaptation measures is essential for projecting the evolving exposure to coastal flooding and erosion, as well as associated community vulnerability through time. A spatially explicit agent-based modeling platform, that provides a scenario-based framework for examining interactions between human and natural systems across a landscape, was used in Tillamook County, OR (USA) to explore strategies that may reduce exposure to coastal hazards within the context of climate change. Probabilistic simulations of extreme water levels were used to assess the impacts of variable projections of sea-level rise and storminess both as individual climate drivers and under a range of integrated climate change scenarios through the end of the century. Additionally, policy drivers, modeled both as individual management decisions and as policies integrated within adaptation scenarios, captured variability in possible human response to increased hazards risk. The relative contribution of variability and uncertainty from both climate change and policy decisions was quantified using three stakeholder relevant landscape performance metrics related to flooding, erosion, and recreational beach accessibility. In general, policy decisions introduced greater variability and uncertainty to the impacts of coastal hazards than climate change uncertainty. Quantifying uncertainty across a suite of coproduced performance metrics can help determine the relative impact of management decisions on the adaptive capacity of communities under future climate scenarios.


2021 ◽  
Author(s):  
Evgeniya Panchenko ◽  
Andrei Alabyan ◽  
Inna Krylenko ◽  
Serafima Lebedeva

<p>Possible sea level rise and changes in hydrological regime of rivers are the major threats to estuarine systems. The sensibility of hydrodynamic regime of the Northern Dvina delta and the Onega estuary under various scenarios of climate change has been investigated. Hydrodynamic models HEC-RAS (USA, US Army Corps of Engineers Hydrologic Engineering Center) and STREAM_2D (Russia, authors V.Belikov et.al.) were used for analysis of estuarine flow regime (variations of water levels, discharges and flow velocities throughout tidal cycles). Input runoff changes were simulated for different climate scenarios using ECOMAG model (Russia, author Yu.Motovilov) based on data of global climate models (GSM) of CMIP5 project for the White Sea region.</p><p>ECOMAG modelling has demonstrated that the maximum river discharges averaged for 30-year period 2036 – 2065 can reduce for about 20 – 27% for the Onega and 15 – 20% for the Northern Dvina river compared against the historical period 1971 – 2000.Averaged minimum river discharges can reduce for about 33 – 45% for the Onega and 30 – 40% for the Northern Dvina.</p><p>The White Sea level rise by 0.27 m in average (with inter-model variation from 0.20 to 0.38 m) can took place by the middle of the XXI century according to input data of GSM models. The 12 scenarios of estuarine hydrodynamic changes were simulated for the both rivers based on combining river runoff changes and sea level elevation.</p><p>In general, the expected flow changes are negative for the local industry and population. According to modelling results for ‘high runoff/spring tide’ scenarios the flooding area in the Northern Dvina delta will increase by 13-20% depending on the intensity of sea level rise. In the low water seasons the distance from the river mouth to the upper boundary of the reach, where reverse currents can be observed, will move upstream by 8 - 36 km depending of sea/river conditions due to decrease in minimum river runoff. It may adversely effect on shipping conditions at the city of Arkhangelsk and on brackish water intrusion up-to industrial and communal water intakes.</p><p>The reverse currents also will intensify in the Onega estuary (tidal flow velocities increase for 11 – 19%) that leads to the change of the sediment regime and can significantly deteriorate the navigation conditions at the seaport of the Onega town. The problem of the intensification of salt intrusion can arise there as well.</p><p>The research was supported by the Russian Foundation for Basic Research (Projects No. 18- 05-60021 in development of the scenarios; No. 19-35-90032 in providing hydrodynamic modelling of the Onega; Project No. 19-35-60032 in providing hydrodynamic modelling of the Northern Dvina).</p>


Atmosphere ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 95
Author(s):  
Phil J. Watson

This paper provides an Extreme Value Analysis (EVA) of the hourly water level record at Fort Denison dating back to 1915 to understand the statistical likelihood of the combination of high predicted tides and the more dynamic influences that can drive ocean water levels higher at the coast. The analysis is based on the Peaks-Over-Threshold (POT) method using a fitted Generalised Pareto Distribution (GPD) function to estimate extreme hourly heights above mean sea level. The analysis highlights the impact of the 1974 East Coast Low event and rarity of the associated measured water level above mean sea level at Sydney, with an estimated return period exceeding 1000 years. Extreme hourly predictions are integrated with future projections of sea level rise to provide estimates of relevant still water levels at 2050, 2070 and 2100 for a range of return periods (1 to 1000 years) for use in coastal zone management, design, and sea level rise adaptation planning along the NSW coastline. The analytical procedures described provide a step-by-step guide for practitioners on how to develop similar baseline information from any long tide gauge record and the associated limitations and key sensitivities that must be understood and appreciated in applying EVA.


2019 ◽  
Vol 11 (3) ◽  
pp. 277 ◽  
Author(s):  
Suresh Palanisamy Vadivel ◽  
Duk-jin Kim ◽  
Jungkyo Jung ◽  
Yang-Ki Cho ◽  
Ki-Jong Han ◽  
...  

Vertical land motion at tide gauges influences sea level rise acceleration; this must be addressed for interpreting reliable sea level projections. In recent years, tide gauge records for the Eastern coast of Korea have revealed rapid increases in sea level rise compared with the global mean. Pohang Tide Gauge Station has shown a +3.1 cm/year sea level rise since 2013. This study aims to estimate the vertical land motion that influences relative sea level rise observations at Pohang by applying a multi-track Persistent Scatter Interferometric Synthetic Aperture Radar (PS-InSAR) time-series analysis to Sentinel-1 SAR data acquired during 2015–2017. The results, which were obtained at a high spatial resolution (10 m), indicate vertical ground motion of −2.55 cm/year at the Pohang Tide Gauge Station; this was validated by data from a collocated global positioning system (GPS) station. The subtraction of InSAR-derived subsidence rates from sea level rise at the Pohang Tide Gauge Station is 6 mm/year; thus, vertical land motion significantly dominates the sea level acceleration. Natural hazards related to the sea level rise are primarily assessed by relative sea level changes obtained from tide gauges; therefore, tide gauge records should be reviewed for rapid vertical land motion along the vulnerable coastal areas.


Ocean Science ◽  
2015 ◽  
Vol 11 (4) ◽  
pp. 617-628 ◽  
Author(s):  
Q. H. Luu ◽  
P. Tkalich ◽  
T. W. Tay

Abstract. Sea level rise due to climate change is non-uniform globally, necessitating regional estimates. Peninsular Malaysia is located in the middle of Southeast Asia, bounded from the west by the Malacca Strait, from the east by the South China Sea (SCS), and from the south by the Singapore Strait. The sea level along the peninsula may be influenced by various regional phenomena native to the adjacent parts of the Indian and Pacific oceans. To examine the variability and trend of sea level around the peninsula, tide gauge records and satellite altimetry are analyzed taking into account vertical land movements (VLMs). At annual scale, sea level anomalies (SLAs) around Peninsular Malaysia on the order of 5–25 cm are mainly monsoon driven. Sea levels at eastern and western coasts respond differently to the Asian monsoon: two peaks per year in the Malacca Strait due to South Asian–Indian monsoon; an annual cycle in the remaining region mostly due to the East Asian–western Pacific monsoon. At interannual scale, regional sea level variability in the range of ±6 cm is correlated with El Niño–Southern Oscillation (ENSO). SLAs in the Malacca Strait side are further correlated with the Indian Ocean Dipole (IOD) in the range of ±5 cm. Interannual regional sea level falls are associated with El Niño events and positive phases of IOD, whilst rises are correlated with La Niña episodes and negative values of the IOD index. At seasonal to interannual scales, we observe the separation of the sea level patterns in the Singapore Strait, between the Raffles Lighthouse and Tanjong Pagar tide stations, likely caused by a dynamic constriction in the narrowest part. During the observation period 1986–2013, average relative rates of sea level rise derived from tide gauges in Malacca Strait and along the east coast of the peninsula are 3.6±1.6 and 3.7±1.1 mm yr−1, respectively. Correcting for respective VLMs (0.8±2.6 and 0.9±2.2 mm yr−1), their corresponding geocentric sea level rise rates are estimated at 4.4±3.1 and 4.6±2.5 mm yr−1. The geocentric rates are about 25 % faster than those measured at tide gauges around the peninsula; however, the level of uncertainty associated with VLM data is relatively high. For the common period between 1993 and 2009, geocentric sea level rise values along the Malaysian coast are similar from tide gauge records and satellite altimetry (3.1 and 2.7 mm yr−1, respectively), and arguably correspond to the global trend.


2014 ◽  
Vol 8 (9) ◽  
pp. 6483-6495 ◽  
Author(s):  
A. Parker ◽  
C. D. Ollier

2017 ◽  
Author(s):  
Aiqing Feng ◽  
Jiangbo Gao ◽  
Shaohong Wu ◽  
Yanzhong Li ◽  
Xiliu Yue

Abstract. Extreme water levels, caused by the joint occurrence of storm surges and high tides, always lead to super floods along coastlines. Given the ongoing climate change, this study explored the risk of future sea-level rise on the extreme inundation by combining P-III model and losses assessment model. Taking Rongcheng as a case study, the integrated risk of extreme water levels was assessed for 2050 and 2100 under three Representative Concentration Pathways (RCP) scenarios of 2.6, 4.5, and 8.5. Results indicated that the increase in total direct losses would reach an average of 60 % in 2100 as a 0.82 m sea-level rise under RCP 8.5. In addition, affected population would be increased by 4.95 % to 13.87 % and GDP (Gross Domestic Product) would be increased by 3.66 % to 10.95 % in 2050 while the augment of affected population and GDP in 2100 would be as twice as in 2050. Residential land and farmland would be under greater flooding risk in terms of the higher exposure and losses than other land-use types. Moreover, this study indicated that sea-level rise shortened the recurrence period of extreme water levels significantly and extreme events would become common. Consequently, the increase in frequency and possible losses of extreme flood events suggested that sea-level rise was very likely to exacerbate the extreme risk of coastal zone in future.


Eos ◽  
2016 ◽  
Vol 97 ◽  
Author(s):  
Leah Crane

Tide gauges can help measure sea level change, but their limited locations and short records make it hard to pinpoint trends. Now researchers are evaluating the instruments' limitations.


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