California coastal management with a changing climate

With over 2,000 miles (3,218 km) of ocean and estuarine coastline, California faces significant coastal management challenges as a result of climate change-induced sea level rise. Under high emission scenarios, recent models predict 1.4 m or more of sea level rise by 2100, accompanied by increasing storm surges. This article investigates the most important issues facing coastal managers, explores the policy tools available for adapting to the impacts of climate change, assesses institutional constraints to adaptation, and identifies priorities for future research and policy action. We find that adaptation tools exist for dealing with anticipated increases in coastal erosion and flooding, but they involve significant costs and tradeoffs. In particular, coastal armoring, such as seawalls, can protect developed coastal lands, but destroys beaches and habitat. Although California already has policies and institutions that aim to balance the competing objectives for coastal development, management agencies are at the early stages of understanding how to facilitate adaptation. Research priorities to inform coastal adaptation planning include: (i) inventorying coastal resources to provide a firmer basis for balancing decisions on property and habitat protection, (ii) identifying opportunities for coastal habitat migration, (iii) assessing the vulnerabilities of existing and planned coastal infrastructure, and (iv) experimenting with alternatives to armoring as a way of managing the changing coastline.     

Regional impact assessment of flooding under future climate and socio-economic scenarios for East Anglia and North West England

Interactive tools developed within the RegIS project for assessing the impacts of flooding provide information to support flood management policies and analyse the performance of possible adaptation activities to climate change. This paper describes the methodologies used in the development of these tools including tidal and fluvial flooding processes with different levels of climate pressures, represented by changes in sea level and peak river flows. Potential impacts of climate change for East Anglia and North West England are explored to the 2050s using four socio-economic scenarios to represent plausible futures. This includes changes in urban land use as well as adaptive responses to flooding comprising dike upgrade and realignment options. The results indicate that future climate will increase flood risk in both regions. East Anglia is more vulnerable to climate change than North West England at the present level of protection, especially in the extensive coastal lowlands of the Fens and Broads because of the combined effects of sea-level rise and increased fluvial flows. Although the present adaptive policy of upgrading defences in East Anglia will reduce the impacts of flooding, this policy is not effective in the case of the more extreme climate change scenarios by 2050s. In this case, more extensive adaptation would be required.     

The present and future role of coastal wetland vegetation in protecting shorelines: answering recent challenges to the paradigm

For more than a century, coastal wetlands have been recognized for their ability to stabilize shorelines and protect coastal communities. However, this paradigm has recently been called into question by small-scale experimental evidence. Here, we conduct a literature review and a small meta-analysis of wave attenuation data, and we find overwhelming evidence in support of established theory. Our review suggests that mangrove and salt marsh vegetation afford context-dependent protection from erosion, storm surge, and potentially small tsunami waves. In biophysical models, field tests, and natural experiments, the presence of wetlands reduces wave heights, property damage, and human deaths. Meta-analysis of wave attenuation by vegetated and unvegetated wetland sites highlights the critical role of vegetation in attenuating waves. Although we find coastal wetland vegetation to be an effective shoreline buffer, wetlands cannot protect shorelines in all locations or scenarios; indeed large-scale regional erosion, river meandering, and large tsunami waves and storm surges can overwhelm the attenuation effect of vegetation. However, due to a nonlinear relationship between wave attenuation and wetland size, even small wetlands afford substantial protection from waves. Combining man-made structures with wetlands in ways that mimic nature is likely to increase coastal protection. Oyster domes, for example, can be used in combination with natural wetlands to protect shorelines and restore critical fishery habitat. Finally, coastal wetland vegetation modifies shorelines in ways (e.g. peat accretion) that increase shoreline integrity over long timescales and thus provides a lasting coastal adaptation measure that can protect shorelines against accelerated sea level rise and more frequent storm inundation. We conclude that the shoreline protection paradigm still stands, but that gaps remain in our knowledge about the mechanistic and context-dependent aspects of shoreline protection.     

Impact of justice and solidarity variables on the acceptability of managed realignment

Sea-level rise due to climate change will have significant effects on coastal areas and populations. Adaptation policies recommend the managed realignment of the most vulnerable assets and activities. Despite their medium- and long-term benefits, these policies face significant friction due to social acceptability in the communities where they are implemented.

This article investigates the hypothesis that respecting principles of justice in the implementation of managed realignment should increase its acceptability. We compare preferences of those people who are exposed to the risk of climate-change-induced flooding and those who are not, as regards funding managed retreat policies and defining compensation criteria for assets at risk. The main theories of social justice provide the four principles included in the analysis: efficiency, need, responsibility and priority assigned to property rights.

A choice experiment survey was conducted with 258 residents of coastal and hinterland communities in the south of France. Four attributes were selected to define the managed realignment policy: the dialogue arrangements, the implementation period, the policy implementation schedule and the cost. The results show support for a relatively fast launch of these policies (within 15 years) but in stages and through a process of dialogue with the population. People's perceptions of the funding criteria reveal a preference for national solidarity. Finally, national funding of managed retreat policies and compensation criteria based on market prices have a significant positive influence on the acceptability of managed realignment policies, whereas introducing responsibility-based compensation criteria tends to favour the status quo over the adaptation policy.

Policy relevance

Prioritization of the funding criteria reveals the preference for national solidarity. Preferences for the justice criteria underpinning compensation reveal a great diversity of values. Besides implantation modalities, preferences for managed realignment policies depend on which level they are implemented at, on the expropriation criteria (the emphasis given to property rights, i.e. market price), on the attachment (people perceived as worst off, i.e. the property is their main residence rather than a second home or they have lower levels of income) and on the degree of responsibility (related to the date of purchase, i.e. on the information given at the time on the risk).     

Territorial inertia versus adaptation to climate change. When local authorities discuss coastal management in a French Mediterranean region

Adaptation to climate change is a critical issue in coastal areas, at risk from sea-level rise, erosion, and sea flooding. In territories strongly urbanized and long oriented toward tourism and a residential economy, a change in coastal management and territorial development is hard to initiate. In Provence-Alpes-Côte d'Azur (France), a leading tourism region, this article explores how local authorities perceive climate change and talk about adaptation strategies. Interviews with municipal-level authorities, both elected officials and technical agents, reveal the influence of territorial inertia, with persistent statements promoting the beach- and residential-oriented economy and a wait-and-see attitude regarding climate change. Beach erosion is the only coastal risk interviewees really recognize, while sea-level rise and sea flooding are barely perceived. Yet evidence supporting the possibility of a future change in position is provided by the younger generation of interviewees, who are more aware of environmental challenges. Providing original data for a coastal region often considered as a model of development throughout the world, this article also proposes an original and transferable method combining geographical sampling of municipalities, text statistics and qualitative analysis of interviews, to apprehend the social representations of the coast, of climate change and coastal risks. Such a methodology is recommended prior to any quantitative assessment of climate action at local scale.     

Integrated analysis of risks of coastal flooding and cliff erosion under scenarios of long term change

The risks to human populations in coastal areas are changing due to climate and socio-economic changes, and these trends are predicted to accelerate during the twenty-first century. To understand these changing risks, and the resulting choices and pathways to successful management and adaptation, broad-scale integrated assessment is essential. Due to their complexity the two risks of flooding and erosion are usually managed independently, yet frequently they are interconnected by longshore exchange of sediments and the resulting broad scale morphological system behaviour. In order to generate new insights into the effects of climate change and coastal management practises on coastal erosion and flood risk, we present an integrated assessment of 72 km of shoreline over the twenty-first century on the East Anglian coast of England which is a site of significant controversy about how to manage coastal flood and erosion risks over the twenty-first century. A coupled system of hydrodynamic, morphological, reliability and socio-economic models has been developed for the analysis, implemented under scenarios of coastal management, climate and socio-economic change. The study is unique in coastal management terms because of the large spatial scale and extended temporal scale over which the analysis is quantified. This study for the first time quantifies what has for some years been argued qualitatively: the role of sediments released from cliff erosion in protecting neighbouring low-lying land from flooding. The losses and benefits are expressed using the common currency of economic risk. The analysis demonstrates that over the twenty-first century, flood risk in the study area is expected to be an order of magnitude greater than erosion risk. Climate and socio-economic change and coastal management policy have a significant influence on flood risk. This study demonstrates that the choices concerning coastal management are profound, and there are clear tradeoffs between erosion and flood impacts.     

The economic value of delaying adaptation to sea-level rise: An application to coastal properties in Connecticut

The magnitude and frequency of coastal storms are expected to increase with rising global sea levels, which necessitates evaluating coastal flood adaptation measures. This study examines an important issue in the context of coastal flood protection, namely, the decision when to adopt protection measures. For any given coastal region, our benefit-cost framework allows us to determine the optimal timing of initiating protection that maximizes expected net benefits. We present an application of this framework to a coastal area in Connecticut. Our results suggest that the optimal timing of adopting protection may vary across different census blocks within the study area. We find that using a relatively low discount rate in the benefit-cost analysis implies greater heterogeneity in the timing decisions and earlier overall adoption, whereas, with higher discount rates, the timing decisions are reduced to a choice between early protection and no protection at all. If possible negative environmental and aesthetic impacts of sea barriers are taken into account, delaying protection would become more desirable, with the extent of delay being sensitive to the relative magnitude of one-time costs (e.g., loss of ocean view and recreational opportunities) vs. continuous costs (e.g., shoreline erosion and loss of wetlands).     

A 3-D sea breeze model of the PBL including pollutant dispersion

A 3-D sea breeze model has been developed to study the sea breeze and the pollutant dispersion over a coastal area. Topography is also included. Similarity theory is adopted while a turbulent kinetic energy equation is used to study turbulence and to parameterize eddy diffusion. The integration is repeated in diurnal cycles and the results — meteorological and pollutant — are compared with data from the Athens area.     

Simulations of Hurricane Katrina (2005) under sea level and climate conditions for 1900

Global warming may result in substantial sea level rise and more intense hurricanes over the next century, leading to more severe coastal flooding. Here, observed climate and sea level trends over the last century (c. 1900s to 2000s) are used to provide insight regarding future coastal inundation trends. The actual impacts of Hurricane Katrina (2005) in New Orleans are compared with the impacts of a similar hypothetical hurricane occurring c. 1900. Estimated regional sea level rise since 1900 of 0.75 m, which contains a dominant land subsidence contribution (0.57 m), serves as a ‘prototype’ for future climate-change induced sea level rise in other regions. Landform conditions c. 1900 were estimated by changing frictional resistance based on expected additional wetlands at lower sea levels. Surge simulations suggest that flood elevations would have been 15 to 60 % lower c. 1900 than the conditions observed in 2005. This drastic change suggests that significantly more flood damage occurred in 2005 than would have occurred if sea level and climate conditions had been like those c. 1900. We further show that, in New Orleans, sea level rise dominates surge-induced flooding changes, not only by increasing mean sea level, but also by leading to decreased wetland area. Together, these effects enable larger surges. Projecting forward, future global sea level changes of the magnitude examined here are expected to lead to increased flooding in coastal regions, even if the storm climate is unchanged. Such flooding increases in densely populated areas would presumably lead to more widespread destruction.     

Significance of nitrogen dioxide absorption in estimating aerosol optical depth and size distributions

Abstract

Changes to the Beaufort Sea shoreline occur due to the impact of storms and rising relative sea level. During the open‐water season (June to October), storm winds predominantly from the north‐west generate waves and storm surges which are effective in eroding thawing ice‐rich cliffs and causing overwash of gravel beaches. Climate change is expected to be enhanced in Arctic regions relative to the global mean and include accelerated sea‐level rise, more frequent extreme storm winds, more frequent and extreme storm surge flooding, decreased sea‐ice extent, more frequent and higher waves, and increased temperatures. We investigate historical records of wind speeds and directions, water levels, sea‐ice extent and temperature to identify variability in past forcing and use the Canadian Global Coupled Model ensembles 1 and 2 (CGCM1 and CGCM2) climate modelling results to develop a scenario forcing future change of Beaufort Sea shorelines. This scenario and future return periods of peak storm wind speeds and water levels likely indicate increased forcing of coastal change during the next century resulting in increased rates of cliff erosion and beach migration, and more extreme flooding.     

CLIMATE CHANGE VULNERABILITY AND RESPONSE STRATEGIES FOR THE COASTAL ZONE OF POLAND

Four accelerated sea level rise scenarios, 30 and 100 cm by the year 2100, and 10 and 30 cm by the year 2030, have been assumed as boundary conditions (along with some wind climate changes) for the entire Polish coast, under two recent programmes completed in 1992 and 1995. Three adaptation strategies, i.e., retreat, limited protection and full protection have been adopted and compared in physical and socio-economic terms. Over 2,200 km² and 230,000 people are found vulnerable in the most severe case of 100-cm rise by 2100. The total cost of land at loss in that case is estimated at nearly 30 USD billion (plus some 18 USD billion at risk of flooding), while the cost of full protection reaches 6 USD billion. Particular features of vulnerability and adaptation schemes have been examined as well, including specific sites and the effects of not only sea level rise but also other climate change factors, and interactions with other climate change studies in Poland. Planning of coastal zone management facing climate change can be facilitated by the use of a GIS-supported coastal information and analysis system. An example of the application of such a system for a selected Polish coastal site is shown to illustrate the most recent smaller-scale research activities undertaken in the wake of the overall assessment of the vulnerability to climate change for the entire Polish coastal zone.     

A conceptual template for integrative human–environment research

Knowledge integration, the blending of concepts from two or more disciplines to create innovative new worldviews, is a key process in attempts to increase the sustainability of human activities on Earth. In this paper, we describe a ‘conceptual template’ that can be used to catalyse this process. The template comprises (a) a list of high-level concepts that capture the essential aspects of any significant human–environment problem, plus (b) broad lists of low-level basic concepts drawn from a range of disciplines. Our high-level concepts, which we call ‘conceptual clusters’, are labelled Dynamics & System, Organisation & Scale, Controlling Models, Management & Policy, Adaptation & Learning, and History. Many of the clustered, lower-level concepts are synonyms and thus provide possible connections between disciplines—for this reason we call them ‘nexus concepts’. We suggest that a conceptual template like that presented here can provide strong support to the initial phases of integrative research programs.     

Global Warming and Coastal Erosion

One of the most certain consequences of global warming is an increase of global (eustatic) sea level. The resulting inundation from rising seas will heavily impact low-lying areas; at least 100 million persons live within one meter of mean sea level and are at increased risk in the coming decades. The very existence of some island states and deltaic coasts is threatened by sea level rise. An additional threat affecting some of the most heavily developed and economically valuable real estate will come from an exacerbation of sandy beach erosion. As the beach is lost, fixed structures nearby are increasingly exposed to the direct impact of storm waves, and will ultimately be damaged or destroyed unless expensive protective measures are taken. It has long been speculated that the underlying rate of long-term sandy beach erosion is two orders of magnitude greater than the rate of rise of sea level, so that any significant increase of sea level has dire consequences for coastal inhabitants. We present in this paper an analytical treatment that indicates there is a highly multiplicative association between long-term sandy beach erosion and sea level rise, and use a large and consistent data base of shoreline position field data to show that there is reasonable quantitative agreement with observations of 19th and 20th century sea levels and coastal erosion. This result means that the already-severe coastal erosion problems witnessed in the 20th century will be exacerbated in the 21st century under plausible global warming scenarios.     

Managing shoreline retreat: a US perspective

As sea level rises, coastal communities will face increased risks of flooding, storm surge, and inundation. In some areas, structural protective measures will be built, and for some properties, accommodation to sea level rise may be possible. For other areas, however, some form of retreat will be either preferred on economic or sociopolitical grounds or required given fiscal constraints. This paper considers how society can proactively manage shoreline retreat in those locations where it is deemed the preferable policy. A three-part strategy is proposed: (1) reduce new development in the highest-risk areas; (2) adopt policies that allow for expected and orderly removal or modification of development as inundation occurs; and (3) take advantage of disasters to implement managed retreat approaches. Specific policies are recommended and the challenges of institutional change discussed.     

‘Earth system governance’ as a crosscutting theme of global change research

In 2001, the four global change research programmes ‘urgently’ called for ‘an ethical framework for global stewardship and strategies for Earth System management’. Yet this notion of ‘earth system management’ remains vaguely defined: It is too elusive for natural scientists, and too ambitious or too normative for social scientists. In this article, I develop an alternative concept that is better grounded in social science theory: ‘earth system governance’. I introduce, first, the concept of earth system governance as a new social phenomenon, a political programme and a crosscutting theme of research in the field of global environmental change. I then sketch the five key problem structures that complicate earth system governance, and derive from these four overarching principles for earth system governance as political practice, namely credibility, stability, adaptiveness, and inclusiveness. In the last part of the article, I identify five research and governance challenges that lie at the core of earth system governance as a crosscutting theme in global change research. These are the problems of the overall architecture of earth system governance, of agency beyond the state, of the adaptiveness of governance mechanisms and of their accountability and legitimacy, and of the modes of allocation in earth system governance—in short, the five A's of earth system governance research.     

Does the Aral sea merit heritage status?

In November 1972, the United Nations developed the World Heritage Convention in recognition of the need for protecting valuable cultural and natural sites of global importance. The convention was designed to identify and protect heritage sites worldwide. Although the Aral Sea has not yet been proposed by any of the Central Asian states as a world heritage site, it meets many of the criteria designated by the Convention as a site meriting such status. The purpose of this paper is threefold. First, the notion of heritage and its application to world heritage status are discussed. Second, this notion is applied to the Aral Sea Basin in Central Asia in an attempt to answer the question, ‘Does the Aral Sea merit heritage status?’. Finally, ‘environmental Justice’ issues, which might arise as a result of such a designation, are discussed.     

An assessment of the physical impacts of sea-level rise and coastal adaptation: a case study of the eastern coast of Ghana

Sea-level rise is a major coastal issue in the 21st century because many of the world??s built assets are located in the coastal zone. Coastal erosion and flooding are serious threats along the coast of Ghana, particularly, the eastern coast where the Volta delta is located. Past human interventions, climate change and the resultant rise in sea-levels, increased storm intensity and torrential rainfall have been blamed for these problems. Accelerated sea-level rise and storm surge pose serious threat to coastal habitat, bio-diversity and socio-economic activities in the coastal zone of Ghana and elsewhere. There is the need for an holistic assessment of the impacts of sea-level rise on the coast zone in order to formulate appropriate adaptation policies and strategies to mitigate the possible effects. Using the eastern coast of Ghana as a case study, this paper assesses the physical impacts of accelerated sea level rise and storm surge on the coastal environment. It evaluates adaptation policies and plans that could be implemented to accommodate the present and any future impacts. Field investigation and Geographic Information System (GIS) are among the methods used for the assessment. The outcome of the assessment has provided comprehensive knowledge of the potential impacts of accelerated sea-level rise and storm surge on the eastern coast. It has facilitated identification of management units, the appraisal of alternate adaptation policies and the selection of the best policy options based upon the local conditions and environmental sustainability. Among other things, this paper reveals that the eastern coast of Ghana is highly vulnerable to accelerated sea-level rise and therefore, requires sustainable adaptation policies and plans to manage the potential impacts. It recommends that various accommodation policies, which enable areas to be occupied for longer before eventual retreat, could be adapted to accommodate vulnerable settlements in the eastern coast of Ghana.     

The new climate discourse: Alarmist or alarming?

The discourse on climate change is in part divided between a sense of alarm and a sense of alarmism in assessments of the magnitude and urgency of the problem. The divide in the discourse among climatologists relates to tensions in the use of key phrases to describe climate change. This article reviews evidence to support claims that climate change can be viewed as ‘catastrophic’, ‘rapid’, ‘urgent’, ‘irreversible’, ‘chaotic’, and ‘worse than previously thought’. Each of these terms are imprecise and may convey a range of meaning. The method used here is to assess whether the conventional understandings of these terms are broadly consistent or inconsistent with the science, or else ambiguous. On balance, these terms are judged to be consistent with the science. Factors which divide climatologists on this discourse are also reviewed. The divide over a sense of urgency relates to disagreement on the manner and rate at which ice sheets breakdown in response to sustained warming. Whether this rate is fast or slow, the amount of time available to reduce emissions sufficient to prevent ice sheet breakdown is relatively short, given the moderate levels of warming required and the inertia of the climate and energy systems. A new discourse is emerging which underscores the scope of the problem and the scope and feasibility of solutions. This discourse differentiates itself from existing discourses which view the magnitudes of the problem or of solutions as prohibitive.     

Evaluating the Global Environment Facility: A goodwill gesture or a serious attempt to deliver global benefits?

Over its 17 years, the UN's Global Environment Facility (GEF) has allocated US $7.5 billion intended to develop and implement scientifically and socially credible solutions to key global environmental problems such as climate change, biological diversity loss and degradation of transboundary aquatic systems. We studied 906 GEF projects to analyse the challenges that it is facing in delivering solutions that are likely to be sustainable in the long-term. The research included desk reviews of relevant documents and follow-up interviews with a wide range of stakeholders. Some of the challenges the GEF faces are deeply rooted in temporal and spatial mismatches of scale between human economies and their environmental consequences and the strongly sectoral way current society is managed. We conclude that the GEF obtained impressive results for tackling problems of limited complexity and easily quantified benefits but progress is slower on more complex and less tangible problems impeding sustainable development. Potentially, the GEF could enable adaptive management through a ‘learning by doing’ process, transforming it into an innovative mechanism for delivering global benefits. Continued emphasis on ‘easy wins’ would not allow it to achieve this goal.     

Global warming and hurricanes: the potential impact of hurricane intensification and sea level rise on coastal flooding

Tens of millions of people around the world are already exposed to coastal flooding from tropical cyclones. Global warming has the potential to increase hurricane flooding, both by hurricane intensification and by sea level rise. In this paper, the impact of hurricane intensification and sea level rise are evaluated using hydrodynamic surge models and by considering the future climate projections of the Intergovernmental Panel on Climate Change. For the Corpus Christi, Texas, United States study region, mean projections indicate hurricane flood elevation (meteorologically generated storm surge plus sea level rise) will, on average, rise by 0.3 m by the 2030s and by 0.8 m by the 2080s. For catastrophic-type hurricane surge events, flood elevations are projected to rise by as much as 0.5 m and 1.8 m by the 2030s and 2080s, respectively.