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Local government organisations in coastal Australia have historically commissioned studies aimed at understanding risks in their locality to future sea level rise as a starting point for developing adaptation strategies to climate change. Therefore, the success of the overall adaptation activities of local government are strongly influenced by the way those initial risk studies are scoped and conducted, and how the outputs of those studies underpin subsequent adaptation planning activities within the organization. Mainstreaming of adaptation planning activities within local government is critical in terms of getting stakeholder support and required resources for its implementation. This paper analyses a sample of these coastal risk assessment studies across seven states and territories in Australia, with an aim to critically investigate the current state of practice among coastal local governments. First, we develop a typology of studies that have been undertaken by or for practitioners to understand coastal climate change risks, and discuss the applicability of the studies within the policy-making context of local government. Second, we identify a set of sample studies from the ‘grey literature’ through a systematic process and investigate to what extent they adhere to best practice risk management guidelines and principles, such as ISO31000. Third, we interview stakeholders from top performing studies to identify how/if the risk studies helped their organization in progressing their adaptation planning. We find that there is a significant inconsistency among terminologies in the coastal climate change risk assessment unpublished literature as studies use “risk”, vulnerability” and “hazard” concepts interchangeably despite their separate objectives and aims. Most studies perform poorly in evaluating risk against broader organizational criteria. Subsequently, it is difficult to integrate the findings of such studies into a broader organizational risk register, limiting opportunities for identified coastal climate change risks to be integrated into councils’ long-term strategic decision making. Conversely, the follow up interviews of studies that performed well in scoping and consultation in our assessment demonstrate that these aspects were beneficial to stakeholders in terms of informing adaptation planning. Importantly, the findings presented in this paper confirm the need for a consistent risk assessment approach for local councils in the coastal zone to underpin successful adaptation planning. This is a critical issue, not only for Australia, but for local government organisations globally given that sea level rise is a projected threat for all populated coastal regions worldwide. [ABSTRACT FROM AUTHOR]

Decision-makers, managers and communities in low-lying coastal regions face many challenges in planning for and adapting to escalating coastal hazard risk, given uncertainty about sea-level rise and complex and contested environmental and socio-economic futures. Collaborative and participatory approaches can help to address such challenges and enable proactive adaptation. However, there is limited empirical evidence of such approaches yielding outcomes that can genuinely be described as shifting business as usual, and fewer still that have informed institutional change. This paper provides such evidence based on an assessment of a novel collaboration between local government, Māori, stakeholders, community members, consultants and researchers in the formulation of a 100-year coastal hazard management strategy in Aotearoa New Zealand. Thematic analysis of interviews, surveys and workshop materials was used to distil lessons learned by participants involved in formulating this anticipatory long-term strategy. Results indicated the importance of deliberative, flexible and transparent governance processes that can enable collaboration amongst Māori, local and region-wide stakeholders, in a process consistent with and supported by the national governmental frameworks, and regulatory and non-regulatory measures. The importance of aligning scientific, local and Indigenous knowledges is highlighted. Furthermore, novel tools and methodologies were used in the strategy formulation process, hitherto not applied in a real-life coastal decision-making process, to address changing risk over time and uncertainties. This enabled the tailoring of strategic planning and decision processes to reflect local contexts and governance interactions. Adaptive pathways were developed to enable short-term actions to be taken while leaving open long-term options and alternative pathways available for future adjustment as the hazards and impacts intensify. The lessons learned from the development of the coastal management strategy offer insights to support future collaborative decision-making processes in climate change adaptation. They advance scholarly understanding about how sea-level rise risks can be addressed in a long-term strategic formulation process in a dynamic and 'fit-for-purpose' manner. [Display omitted] • We thematically analysed the formulation of a 100-year coastal hazards strategy. • Key themes emerged to reveal lessons learned from the process. • Collaborative and flexible governance processes contributed to building trust. • Proactive, tailored decision tools enabled development of adaptation pathways. • Scientific, technical, local and Indigenous knowledges were incorporated. [ABSTRACT FROM AUTHOR]

Determining effects of climate change on landscapes involves numerous uncertainties. This paper presents and illustrates a protocol for climate attribution of landscape responses. The major steps are ascertaining potential climate-related responses, establishing plausibility for a climatic influence, identifying alternative or additional causes, testing possible climate and non-climate causes, and interpreting the role of climate and climate change in the landscape response. The protocol is based on existing practice in the historical and interpretive branches of Earth and ecological sciences, and explicitly considers negative (non-confirmatory) results for climate and other factors. The protocol is applied to the conversion of brackish marsh to open water in the upper Neuse River estuary, North Carolina. Conversion since at least the mid twentieth century can be attributed to relative sea-level rise, driven primarily by general climate warming, with no supporting evidence for any additional or alternative drivers. The only other factor with supporting evidence is human modification in the form of ditches, around which conversion was concentrated, though marsh loss also occurred in unditched portions. Rapid recent marsh loss is attributable to Hurricane Florence (2018), particularly the storm surge. Weak positive inferential support exists for a role of climate change in the storm, but aspects of the storm's impact not linked to climate are more important for the marsh conversions. Overall, the landscape response can be linked to climate, exacerbated by direct human impacts of marsh ditching, and strongly influenced by local place factors and the specific storm track. Recent and ongoing climate change is a significant factor, but not paramount, in determining the landscape response. The Neuse River case study is not unusual—and is probably typical—in identifying a combination of climate and other factors strongly influencing landscape response. [Display omitted] • Attributing landscape responses to climate change presents numerous complexities. • Landscape response attribution protocol based on traditional geomorphic approaches • LRA protocol applied to recent conversion of estuarine marsh to open water • Marsh loss due to sea-level rise & major storm, but non-climate factors important • LRA protocol useful to identify & evaluate climate & non-climate drivers of change [ABSTRACT FROM AUTHOR]

This paper describes a probabilistic approach for mapping of coastal flood hazards associated with sea-level rise and storm intensification toward the end of the 21st century. Under the Representative Concentration Pathway (RCP) 8.5, the Coupled Model Intercomparison Project Phase 5 (CMIP5) predicts a 0.6-m ensemble mean of sea-level rise for the Central Pacific from the 1986–2005 to 2081–2100 epochs. Fifty downscaling simulations of the 2080–2099 period from the CMIP5 NCAR-CCSM4 model produce 2492 hurricanes around the Hawaiian Islands. In comparison with a control dataset for the 1980–1999 period, the simulated future hurricanes show a slight increase in number and a northward shift of the tracks toward the Hawaiian Islands. There are 627 hurricanes in the 2080–2099 dataset with potential impact on Oahu, and the top 24 storms selected by wind speed at the urban Honolulu coast define a scenario set for inundation mapping. A suite of spectral wave, circulation, and Boussinesq models in a nested grid system describes generation and propagation of surge and waves across the ocean as well as wave setup and runup at the coast. The interoperable package includes phase-averaged and phase-resolving processes to determine the coastal flood hazards over a range of spatial and temporal scales during a hurricane event. Since the simulated dataset corresponds to a quasi 1000-year period, barring the tail end of the distribution, the suite of inundation scenarios enables definition of flood hazard maps with return periods of up to 500 years or annual exceedance probabilities of 0.2% or greater for climate change adaptation. [ABSTRACT FROM AUTHOR]

Abstract: The paper presents a design exercise of upgrading a typical rock armoured revetment by modifying the structure profile and adding structure elements. Several concepts of upgrading are examined. A sea level rise corresponding to the mean of the IPCC 2007 predictions is used together with a slight increase in long-term wind/wave conditions as predicted for the North Sea by the Danish Coastal Authority. Both conditions of non-acceptable and acceptable increase in structure crest level are considered. Moreover, a scenario for steepening of the foreshore due to morphological changes caused by increased wave impacts is included. Only desk study tools are used for the upgrade designs. A simple comparative cost optimization analysis of the various upgrading solutions is presented, and conclusions are given for the preferred upgrading concept valid for the case study structure. A short discussion of the uncertainties related to upgrading design is included. The importance of physical model tests of the structures is underlined due to insufficient desk study tools for rubble mound upgrade design. [Copyright &y& Elsevier]

Abstract: Analysis of the risks of sea-level rise favours conventionally measured metrics such as the area of land that may be subsumed, the numbers of properties at risk, and the capital values of assets at risk. Despite this, it is clear that there exist many less material but no less important values at risk from sea-level rise. This paper re-theorises these multifarious social values at risk from sea-level rise, by explaining their diverse nature, and grounding them in the everyday practices of people living in coastal places. It is informed by a review and analysis of research on social values from within the fields of social impact assessment, human geography, psychology, decision analysis, and climate change adaptation. From this we propose that it is the ‘lived values’ of coastal places that are most at risk from sea-level rise. We then offer a framework that groups these lived values into five types: those that are physiological in nature, and those that relate to issues of security, belonging, esteem, and self-actualisation. This framework of lived values at risk from sea-level rise can guide empirical research investigating the social impacts of sea-level rise, as well as the impacts of actions to adapt to sea-level rise. It also offers a basis for identifying the distribution of related social outcomes across populations exposed to sea-level rise or sea-level rise policies. [Copyright &y& Elsevier]

Abstract: Long-term change of the global sea level resulting from climate change has become an issue of great societal interest. The advent of the technology of satellite altimetry has modernized the study of sea level on both global and regional scales. In combination with in situ observations of the ocean density and space observations of Earth’s gravity variations, satellite altimetry has become an essential component of a global observing system for monitoring and understanding sea level change. The challenge of making sea level measurements with sufficient accuracy to discern long-term trends and allow the patterns of natural variability to be distinguished from those linked to anthropogenic forcing rests largely on the long-term efforts of altimeter calibration and validation. The issues of long-term calibration for the various components of the altimeter measurement system are reviewed in the paper. The topics include radar altimetry, the effects of tropospheric water vapor, orbit determination, gravity field, tide gauges, and the terrestrial reference frame. The necessity for maintaining a complete calibration effort and the challenges of sustaining it into the future are discussed. [Copyright &y& Elsevier]

Abstract: Holocene environmental change and environmental archaeology are important components of an international project studying the human-earth interaction system. This paper reviews the progress of Holocene environmental change and environmental archaeology research in the Yangtze River Valley over the last three decades, that includes the evolution of large freshwater lakes, Holocene transgression and sea-level changes, Holocene climate change and East Asian monsoon variation, relationship between the rise and fall of primitive civilizations and environmental changes, cultural interruptions and palaeoflood events, as well as relationship between the origin of agriculture and climate change. These research components are underpinned by the dating of lacustrine sediments, stalagmites and peat to establish a chronology of regional environmental and cultural evolution. Interdisciplinary and other environment proxy indicators need to be used in comparative studies of archaeological site formation and natural sedimentary environment in the upper, middle and lower reaches of the Yangtze River Valley. Modern technology such as remote sensing, molecular bioarchaeology, and virtual reality, should be integrated with currently used dating, geochemical, sedimentological, and palaeobotanical methods of analysis in environmental archaeology macro- and micro-studies, so as to provide a greater comprehensive insight into Holocene environmental and cultural interaction and change in the Yangtze River Valley area. [Copyright &y& Elsevier]

Abstract: Changes in coastal habitats brought about by climate change have the potential to cause population decline of shoreline dependent organisms. In particular, sea level rise associated with climate change can drastically affect wetlands and beaches which are important foraging and nesting areas of these organisms. SLAMM 5 (Sea Level Affecting Marshes Model) is widely used to simulate wetland conversion and shoreline modification for the purpose of habitat vulnerability assessment and decision making, but concerns regarding the suitability of the model due to the uncertainty involved in selecting many of the model’s empirical input parameters have been expressed. This paper applies a generic evaluation framework consisting of a state-of-the-art screening and variance-based global sensitivity and uncertainty analyses to simulate changes in the coastal habitats of the barrier island in Eglin Air Force Base, Florida in order to: (1) identify the important input factors and processes that control SLAMM 5’s output uncertainty; (2) quantify SLAMM 5’s global output uncertainty and apportion it to the direct contributions and interactions of the important input factors; and (3) evaluate this new methodology to explore the potential fate of the coastal habitats of the study area. Results showed that four input factors (DEM vertical error for the lower elevation range, historic trend of sea level rise, accretion, and sedimentation rates) controlled 88–91% of SLAMM 5’s output variance in predicting changes in the beach habitat of Eglin Air Force Base. The most dominant processes governing the fate of the coastline of the study area were inundation (i.e. reduction in elevation due to sea level rise) and accretion/sedimentation. Interestingly, for lower elevation habitats (salt marsh, tidal flat, and beach), results showed possible gain or loss of these habitats depending on the relative strength of these processes resulting from the combination of input factors within their proposed uncertainty ranges. Higher-elevation habitats (swamps and inland fresh marsh) showed decrease in area over 100 years of simulation. These findings are important to implement managerial schemes in the area to protect threatened Plover birds (Charadrius sp.) communities. This generic model evaluation framework is model-independent and can be used to evaluate a wide range of environmental models. [Copyright &y& Elsevier]

Abstract: Scenarios are used to explore the consequences of different adaptation and mitigation strategies under uncertainty. In this paper, two scenarios are used to explore developments with (1) no mitigation leading to an increase of global mean temperature of 4°C by 2100 and (2) an ambitious mitigation strategy leading to 2°C increase by 2100. For the second scenario, uncertainties in the climate system imply that a global mean temperature increase of 3°C or more cannot be ruled out. Our analysis shows that, in many cases, adaptation and mitigation are not trade-offs but supplements. For example, the number of people exposed to increased water resource stress due to climate change can be substantially reduced in the mitigation scenario, but adaptation will still be required for the remaining large numbers of people exposed to increased stress. Another example is sea level rise, for which, from a global and purely monetary perspective, adaptation (up to 2100) seems more effective than mitigation. From the perspective of poorer and small island countries, however, stringent mitigation is necessary to keep risks at manageable levels. For agriculture, only a scenario based on a combination of adaptation and mitigation is able to avoid serious climate change impacts. [Copyright &y& Elsevier]

Abstract: This paper examines adaptation to current storm surge flood risk as one indicator of anticipatory adaptation to climate change impacts. Focusing on community businesses, a web-based survey obtained information on hurricane preparedness and risk perceptions in Sarasota County, Florida. A model of current precautionary action that utilized previously identified business characteristics predictive of business preparedness and post-disaster recovery, a spatial variable indicating storm surge exposure, and items measuring the risk perception and information-seeking behavior of business owners explained a majority of the variance in current levels of preparedness. Use of online risk information sources and the geographic distribution of customers and were the strongest predictors of preparedness. Results indicate that the adaptive capacity of businesses may vary significantly with types of businesses, locations, and socio-cognitive characteristics of business owners. To encourage overall community resilience, risk communication efforts should be targeted based on specific elements that predict business preparedness. [Copyright &y& Elsevier]

Summary: Rising sea level together with regionally increased storm activity, caused by elevated and increasing levels of greenhouse gases in the atmosphere will in many parts of the world increase the risk of storm surges significantly. Reducing the emissions of greenhouse gases into the atmosphere may mitigate the increasing risks somewhat, but the major task for regional and local stakeholders will be to prepare for appropriate adaptation. In most cases, possible strategies include intensification of coastal defense measures, in particular strengthening dykes, and adaptation to intermittent flooding. In case of Hamburg and the tidal Elbe river a third option seems to be available, which aims at mitigating storm surge risks by applying estuary engineering constructions. This option is sketched in this paper. The option has the potential to significantly reduce the expected future increases of local surge heights. [Copyright &y& Elsevier]

Abstract: This paper describes the impacts of sea surface temperature (SST) rise and sea-level rise (SLR) on cyclonic storm surge flooding in western Bangladesh. A calibrated numerical hydrodynamic model was used to simulate surge wave propagation through the rivers and overland flooding. The model was calibrated with base condition (present climate), and then eight flooding scenarios of plausible future conditions were assessed by considering increased surge heights. Flooded area, flooding depth and surge intrusion length were computed by superimposing the predicted maximum water level information on a digital elevation model (DEM). This analysis showed that for a storm surge under 2°C SST rise and 0.3m SLR, flood risk area would be 15.3% greater than the present risk area and depth of flooding would increase by as much as 22.7% within 20km from the coastline. Within the risk area, the study identified 5690km2 land (22% of exposed coast) as a high-risk zone (HRZ) where flooding of depth 1m or more might occur, and people should move to nearby cyclone shelters during extreme cyclonic events. Predicted area of HRZ is 1.26 times the currently demarcated HRZ. It was estimated that 320 additional shelters are required to accommodate people in the newly identified HRZ. This information would be of value to policy and decision makers for future shelter planning and designing shelter heights. [Copyright &y& Elsevier]