Sea-level rise impacts on Africa and the effects of mitigation and adaptation: an application of DIVA

This paper assesses sea-level rise impacts on Africa at continental and national scales including the benefits of mitigation and of applying adaptation measures, considering four scenarios of global mean sea-level rises from 64 to 126 cm in the period of 1995–2100. We find that in 2100, 16–27 million people are expected to be flooded per year, and annual damage costs range between US5 and US 5 and US 9 billion, if no adaptation takes place. Mitigation reduces impacts by 11–36%. Adaptation in the form of building dikes to protect against coastal flooding and nourishing beaches to protect against coastal erosion reduces the number of people flooded by two orders of magnitude and cuts damage costs in half by 2100. Following such a protection strategy would require substantial investment. First, Africa’s current adaptation deficit with respect to coastal flooding would need to be addressed. DIVA suggests that a capital investment of US300 billion is required to build dikes adapted to the current surge regime and US 300 billion is required to build dikes adapted to the current surge regime and US 3 billion per year for maintenance. In addition, between US2 and US 2 and US 6 billion per year needs to be spent on protecting against future sea-level rise and socio-economic development by 2100. This suggests that protection is not effective from a monetary perspective but may still be desirable when also taking into account the avoided social impact. We conclude that this issue requires further investigation including sub-national scale studies that look at impacts and adaptation in conjunction with the development agenda and consider a wider range of adaptation options and strategies.     

Regional Risk Assessment addressing the impacts of climate change in the coastal area of the Gulf of Gabes (Tunisia)

Sound, cost efficient management strategies in developed coastal zones can be reinforced by a thorough understanding of risks associated with the combination of anthropogenic and natural drivers of change. A Regional Risk Assessment (RRA) methodology was developed for the assessment of the potential impacts of climate change in the Tunisian coastal zone of the Gulf of Gabes. It is based on the use of Multi-Criteria Decision Analysis techniques and Geographic Information Systems and is designed to support the development and prioritization of adaptation strategies. The RRA focuses on sea-level rise and storm surge flooding impacts for human and natural systems, i.e., beaches, wetlands, urban areas, agricultural areas, and terrestrial ecosystems. Results suggest that for both of the studied climate change impacts, i.e., sea-level rise and storm surge flooding, the area potentially exposed is limited to a narrow, low elevation region adjacent to the shoreline. However, the exposed areas showed a high relative risk score, obtained by the integration of exposure and susceptibility factors. Beaches have the lowest relative risk scores, while wetlands and terrestrial ecosystems have the higher relative risk scores. The final outputs of the analysis (i.e., exposure, susceptibility, and risk maps) can support end-users in the establishment of relative priorities for intervention and in the identification of suitable areas for human settlements, infrastructure, and economic activities, thus providing a basis for coastal zoning and land-use planning.     

Economic,equitable, and affordable adaptations to protect coastal settlements against storm surge inundation

The distribution of risk of coastal inundation, and the potential benefits of adapting to protect against inundation, vary greatly both within and between coastal communities. This diversity is a result of physical factors, such as the risk of storm surge, sea level rise projections, and the topography of the landscape, as well as socio-economic factors, such as the level of development, and the capacity within the community to adapt. Despite this strong local variation, various communities share common characteristics that constrain or enable different adaptation options in different situations. Understanding these drivers is likely to be important in engaging coastal communities in the discussion around adaptation and may provide new insights into which adaptation options are suitable for each of our at-risk coastal communities. We performed a property-level analysis of 6 suburb-sized case studies distributed along the coast of Queensland, Australia. We assessed the potential economic costs of inundation events now and in the future under sea level rise projections, and the potential avoided costs following adaptation to protect against inundation. We went beyond this to estimate the distribution of risk in each community and compared the potential costs of adaptation with the capacity of the community to pay for their implementation. We used these insights to propose a typology of coastal communities based on their exposure to total inundation risk, the distribution of that risk within the community, and their capacity to adapt.     

Physical basis of coastal adaptation on tropical small islands

Small tropical islands are widely recognized as having high exposure and vulnerability to climate change and other natural hazards. Ocean warming and acidification, changing storm patterns and intensity, and accelerated sea-level rise pose challenges that compound the intrinsic vulnerability of small, remote, island communities. Sustainable development requires robust guidance on the risks associated with natural hazards and climate change, including the potential for island coasts and reefs to keep pace with rising sea levels. Here we review these issues with special attention to their implications for climate-change vulnerability, adaptation, and disaster risk reduction in various island settings. We present new projections for 2010–2100 local sea-level rise (SLR) at 18 island sites, incorporating crustal motion and gravitational fingerprinting, for a range of Intergovernmental Panel on Climate Change global projections and a semi-empirical model. Projected 90-year SLR for the upper limit A1FI scenario with enhanced glacier drawdown ranges from 0.56 to 1.01 m for islands with a measured range of vertical motion from ?0.29 to +0.10 m. We classify tropical small islands into four broad groups comprising continental fragments, volcanic islands, near-atolls and atolls, and high carbonate islands including raised atolls. Because exposure to coastal forcing and hazards varies with island form, this provides a framework for consideration of vulnerability and adaptation strategies. Nevertheless, appropriate measures to adjust for climate change and to mitigate disaster risk depend on a place-based understanding of island landscapes and of processes operating in the coastal biophysical system of individual islands.     

THE FOREST–HYDROLOGY–POVERTY NEXUS IN CENTRAL AMERICA: AN HEURISTIC ANALYSIS

A ‘forest–hydrology–poverty nexus’ hypothesis asserts that deforestation in poor upland areas simultaneously threatens biodiversity and increases the incidence of flooding, sedimentation and other damaging hydrological processes. This paper uses rough heuristics to assess the applicability of this hypothesis to two montane forested countries in Central America: Guatemala and Honduras. We do so by using simple rules of thumb to identify watersheds at greater risk of hydrologically significant land use change, using information about land cover, slope, and watershed size. The location of these watersheds is compared to spatial maps of poverty and forests. We find plausible evidence for a forest–biodiversity–poverty connection in Guatemala, and to a lesser extent in Honduras.     

Managing food at urban level through water–energy–food nexus in India: A way towards holistic sustainable development

Environment, Development and Sustainability - With rise in population growth and increasing trend towards urbanization, urban spaces have become ‘hot spots’ for intensive resource use...     

Impacts of predicted sea level rise on land use/land cover categories of the adjacent coastal areas of Mumbai megacity,India

Physical and ecological responses of the coastal areas in the vicinity of Mumbai, India, due to relative sea level rise are examined by different inundation scenarios. Evaluation of potential habitat loss under sea level rise was made by incorporating the land use/land cover (LULC) adopted from the digital elevation model with the satellite imagery. LULC categories overlaid on 1.0, 2.0, 3.0 and 4.0 m coastal elevation showed that the coastal areas of Mumbai were mostly covered by vegetation followed by barren land, agricultural land, urban areas and water bodies. For the relative sea level rise scenarios of 1.0, 2.0, 3.0 and 4.0 m, the tidal inundation areas were estimated to be 257.85, 385.58, 487.56 and 570.63 km², respectively, using GIS techniques. The losses of urban areas were also estimated at 25.32, 41.64, 54.61 and 78.86 km² for the 1.0, 2.0, 3.0 and 4.0 m relative sea level rise, respectively, which is most alarming information for the most populated city on the eastern coast of India. The results conclude that relative sea level rise scenario will lead profound impacts on LULC categories as well as on coastal features and landforms in the adjoining part of Mumbai. The sea level rise would also reduce the drainage gradients that promote flooding condition to rainstorms and subsequently increase saltwater intrusion into coastal regions. Alterations in the coastal features and landforms correlated with inundation characteristics that make the coastal region more vulnerable in the coming decades due to huge development activities and population pressures in Mumbai.     

A roadmap to a green chemical industry in Australia

A ‘roadmap’ has been devised for a progressive greening of the Australian chemical industry over the next two decades. The roadmap is based on a set of interactive principles broadly termed ‘economic’, ‘social’, ‘technological’, ‘environmental’ and ‘political’, which collectively form the ‘drivers of change’ in chemical industry strategy/business/policy planning—leading to greater efficiency and economic sustainability of this industry. The proposed roadmap pre-supposes that real economic, societal and environmental benefits can be obtained through greater use of existing and emerging green chemical technology. It can play an important role in developing a sustainable chemical industry in Australia. Primarily, the proposed roadmap involves a paradigm shift of the business operating plan and a significant mindset change of management.     

‘Eco-city’ to ‘disaster-resilient eco-community’: a concerted approach in the coastal city of Puri, India

The need for environmental and urban planning reached a critical point in the year 2007, when one-half of the world's population could be defined as living in cities. Urbanisation in India is also increasing at a fast rate. Urban chaos in India, emanating from the continuous ignorance of fragile ecosystems, calls for the reshaping of existing cities as ‘eco-cities’. The ‘eco-city’—a well-known concept in the western world—is new to the Indian context. While western connotations of eco-cities should not be discarded outright in the context of India, core concerns vary significantly for obvious reasons. Recognising two facts—firstly, eco-city development is altogether a fresh approach to human settlement development in India, and, secondly, the manifold increase in the vulnerability of cities—this paper discusses documented good practice, reinforcing evolution towards the eco-city vision. Lessons drawn from the examples cited are further deconstructed in the light of their contribution to urban risk reduction, which provides direction to appreciating the ‘disaster-resilient eco-community’ concept in Puri, a coastal city in India. Further, this paper attempts to unravel existing community-based practices in Puri, which are boon to the local environment and invariably reduce disaster risk. These seemingly modest neighbourhood initiatives symbolise immense societal wealth, which can be calibrated appropriately for reducing urban environmental risk as well. This paper also illustrates how a ‘disaster resilient eco-community’ approach is inevitable in the present and future contexts not only to preserve sustainable development gains but also to secure human well-being.     

Heading for the hills: climate-driven community relocations in the Solomon Islands and Alaska provide insight for a 1.5 °C future

Whilst future air temperature thresholds have become the centrepiece of international climate negotiations, even the most ambitious target of 1.5 °C will result in significant sea-level rise and associated impacts on human populations globally. Of additional concern in Arctic regions is declining sea ice and warming permafrost which can increasingly expose coastal areas to erosion particularly through exposure to wave action due to storm activity. Regional variability over the past two decades provides insight into the coastal and human responses to anticipated future rates of sea-level rise under 1.5 °C scenarios. Exceeding 1.5 °C will generate sea-level rise scenarios beyond that currently experienced and substantially increase the proportion of the global population impacted. Despite these dire challenges, there has been limited analysis of how, where and why communities will relocate inland in response. Here, we present case studies of local responses to coastal erosion driven by sea-level rise and warming in remote indigenous communities of the Solomon Islands and Alaska, USA, respectively. In both the Solomon Islands and the USA, there is no national government agency that has the organisational and technical capacity and resources to facilitate a community-wide relocation. In the Solomon Islands, communities have been able to draw on flexible land tenure regimes to rapidly adapt to coastal erosion through relocations. These relocations have led to ad hoc fragmentation of communities into smaller hamlets. Government-supported relocation initiatives in both countries have been less successful in the short term due to limitations of land tenure, lacking relocation governance framework, financial support and complex planning processes. These experiences from the Solomon Islands and USA demonstrate the urgent need to create a relocation governance framework that protects people’s human rights.     

Historical area and shoreline change of reef islands around Tarawa Atoll, Kiribati

Low-lying reef islands on atolls appear to be threatened by impacts of observed and anticipated sea-level rise. This study examines changes in shoreline position on the majority of reef islands on Tarawa Atoll, the capital of Kiribati. It investigates short-term reef-island area and shoreline change over 30 years determined by comparing 1968 and 1998 aerial photography using geographical information systems. Reef islands have substantially increased in size, gaining about 450 ha, driven largely by reclamations on urban South Tarawa, accounting for 360 ha (~80 % of the net change). Widespread erosion and high average accretion rates appear to be related to disjointed reclamations. In rural North Tarawa, most reef islands show stability, with localised changes in areas such as embayments, sand spits and beaches adjacent to, or facing, inter-island channels. Shoreline changes in North Tarawa are largely influenced by natural factors, whereas those in South Tarawa are predominantly affected by human factors and seasonal variability associated with El Niño—Southern Oscillation (ENSO). However, serious concerns are raised for the future of South Tarawa reef islands, as evidence shows that widespread erosion along the ocean and lagoon shorelines is primarily due to human activities and further encroachment onto the active beach will disrupt longshore sediment transport, increasing erosion and susceptibility of the reef islands to anticipated sea-level rise. Appropriate adaptation measures, such as incorporating coastal processes and seasonal variability associated with ENSO when designing coastal structures and developing appropriate management plans, are required, including prohibiting beach mining practices near settlements.     

Socio-economic vulnerability of the megacity of Shanghai (China) to sea-level rise and associated storm surges

Sea-level rise (SLR) poses a significant threat to many coastal areas and will likely have important impacts on socio-economic development in those regions. Located on the eastern coast in China, the megacity of Shanghai is particularly vulnerable to SLR and associated storm surge risks. Using the municipality of Shanghai as a case study, the possible impacts of flooding risks caused by SLR and associated storm surges on socio-economic development in the region were analysed by a Source–Pathway–Receptor–Consequence (SPRC) conceptual model. The projections of flooding risk in the study area were simulated by MIKE21 (a two-dimensional hydrodynamic model) for the three time periods of 2030, 2050 and 2100. An index system for vulnerability assessment was devised, in which flooding depth, density of population, GDP per capita, GDP per unit land, loss rate under flooding and fiscal revenue were selected as the key indicators. A quantitative spatial assessment method based on a GIS platform was established by quantifying each indicator, calculating and then grading the vulnerability index. The results showed that in the 2030 projection, 99.3 % of the areas show no vulnerability to SLR and associated storm surges under the present infrastructure. By 2050, the areas with low, moderate and high vulnerabilities change significantly to 5.3, 8.0 and 23.9 %, respectively, while by 2100, the equivalent figures are 12.9, 6.3 and 30.7 %. The application of the SPRC model, the methodology and the results from this study could assist with the objective and quantitative assessment of the socio-economic vulnerability of other similar coastal regions undergoing the impacts of SLR and associated storm surges. Based on the results of this study, mitigation and adaptation measures should be considered, which include the controlling the rate of land subsidence, the reinforcement of coastal defence systems and the introduction of adaptation in long-term urban planning.     

Community action for environmental restoration: a case study on collective social capital in India

In southern India, tens of thousands of village-level irrigation systems (‘tanks’ and feeder channels) are in disrepair. This paper analyses the results of a local NGO effort that focused on awareness-raising and advice to bring about self-sustained community action for irrigation system restoration. After designing a model structure that contains both motivational and capacity (social capital) factors, it is found that (pre-existing) collective social capital, as measured through five simple indicators, strongly correlates with success of the NGO strategy. The intensity of the NGO’s effort shows a negative correlation with success, however. The discussion focuses on issues of social capital definition and measurement and the practical implications of the concept for environmental action, especially the difference between using existing social capital for environmental management versus the construction of social capital as a basis for later self-sustained environmental work. Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue.     

Conceptualising climate change in rural Australia: community perceptions, attitudes and (in)actions

Public engagement and support is essential for ensuring adaptation to climate change. The first step in achieving engagement is documenting how the general public currently perceive and understand climate change issues, specifically the importance they place on this global problem and identifying any unique challenges for individual communities. For rural communities, which rely heavily on local agriculture industries, climate change brings both potential impacts and opportunities. Yet, to date, our knowledge about how rural residents conceptualise climate change is limited. Thus, this research explores how the broader rural community—not only farmers—conceptualises climate change and responsive activities, focussing on documenting the understandings and risk perceptions of local residents from two small Australian rural communities. Twenty-three semi-structured interviews were conducted in communities in the Eden/Gippsland region on the border of New South Wales and Victoria and the north-east of Tasmania. There are conflicting views on how climate change is conceptualised, the degree of concern and need for action, the role of local industry, who will ‘win’ and ‘lose’, and the willingness of rural communities to adapt. In particular, residents who believed in anthropogenic or human-induced factors described the changing climate as evidence of ‘climate change’, whereas those who were more sceptical termed it ‘weather variability’, suggesting that there is a divide in rural Australia that, unless urgently addressed, will hinder local and national policy responses to this global issue. Engaging these communities in the twenty-first-century climate change debate will require a significant change in terminology and communication strategies.     

What are the implications of sea-level rise for a 1.5, 2 and 3 °C rise in global mean temperatures in the Ganges-Brahmaputra-Meghna and other vulnerable deltas?

Even if climate change mitigation is successful, sea levels will keep rising. With subsidence, relative sea-level rise represents a long-term threat to low-lying deltas. A large part of coastal Bangladesh was analysed using the Delta Dynamic Integrated Emulator Model to determine changes in flood depth, area and population affected given sea-level rise equivalent to global mean temperature rises of 1.5, 2.0 and 3.0 °C with respect to pre-industrial for three ensemble members of a modified A1B scenario. Annual climate variability today (with approximately 1.0 °C of warming) is potentially more important, in terms of coastal impacts, than an additional 0.5 °C warming. In coastal Bangladesh, the average depth of flooding in protected areas is projected to double to between 0.07 and 0.09 m when temperatures are projected at 3.0 °C compared with 1.5 °C. In unprotected areas, the depth of flooding is projected to increase by approximately 50% to 0.21–0.27 m, whilst the average area inundated increases 2.5 times (from 5 to 13% of the region) in the same temperature frame. The greatest area of land flooded is projected in the central and north-east regions. In contrast, lower flood depths, less land area flooded and fewer people are projected in the poldered west of the region. Over multi-centennial timescales, climate change mitigation and controlled sedimentation to maintain relative delta height are key to a delta’s survival. With slow rates of sea-level rise, adaptation remains possible, but further support is required. Monitoring of sea-level rise and subsidence in deltas is recommended, together with improved datasets of elevation.

     

Sea-level rise vulnerability in the countries of the Coral Triangle

Sea-level rise is a major threat facing the Coral Triangle countries in the twenty-first century. Assessments of vulnerability and adaptation that consider the interactions among natural and social systems are critical to identifying habitats and communities vulnerable to sea-level rise and for supporting the development of adaptation strategies. This paper presents such an assessment using the DIVA model and identifies vulnerable coastal regions and habitats in Coral Triangle countries at national and sub-national levels (administrative provinces). The following four main sea-level rise impacts are assessed in ecological, social and economic terms over the twenty-first century: (1) coastal wetland change, (2) increased coastal flooding, (3) increased coastal erosion, and (4) saltwater intrusion into estuaries and deltas. The results suggest that sea-level rise will significantly affect coastal regions and habitats in the Coral Triangle countries, but the impacts will differ across the region in terms of people flooded annually, coastal wetland change and loss, and damage and adaptation costs. Indonesia is projected to be most affected by coastal flooding, with nearly 5.9 million people expected to experience flooding annually in 2100 assuming no adaptation. However, if adaptation is considered, this number is significantly reduced. By the end of the century, coastal wetland loss is most significant for Indonesia in terms of total area lost, but the Solomon Islands are projected to experience the greatest relative loss of coastal wetlands. Damage costs associated with sea-level rise are highest in the Philippines (US $6.5 billion/year) and lowest in the Solomon Islands (US $70,000/year). Adaptation is estimated to reduce damage costs significantly, in particular for the Philippines, Indonesia, and Malaysia (between 68 and 99%). These results suggest that the impacts of sea-level rise are likely to be widespread in the region and adaptation measures must be broadly applied.     

A quantitative risk assessment of waterborne infectious disease in the inundation area of a tropical monsoon region

Flooding and inundation are annual events that occur during the rainy season in Cambodia, and inundation has a strong relationship with human health. This study simulated the coliform bacteria distribution using a hydraulic model and estimated the impact of inundation on public health using a dose–response model. The model parameters were calibrated using field survey data from Cambodia and obtained good agreement with the coliform group count distribution. The results suggest that the impact of inundation on human health is most noticeable in residential areas. The annual average risk of infection during medium-sized flood events is 0.21. The risk due to groundwater use ranges from 0.12 to 0.17 in inundation areas and reaches as high as 0.23 outside the inundation areas. The risk attributed to groundwater use is therefore higher than that for surface water use (0.02–0.06), except in densely populated areas at the city center. There is a high risk for infection with waterborne disease in residential areas, and the annual average risk during small flood events is 0.94. An assessment of possible countermeasures to reduce the risk shows that the control of inundation may bring more risk to public health in Cambodia. Shallower inundation water (<0.3 m) leads to a higher risk of infection, but if the depth is greater than 2 m, the risk is low in residential areas. The simulated results explain the spatial distributions of infection risk,, which are vitally important for determining the highest priority places with relatively high risk and will be helpful for decision makers when considering the implementation of countermeasures.     

A stakeholder dialogue on European vulnerability

A stakeholder dialogue was embedded in the ATEAM project to facilitate the development and dissemination of its European-wide vulnerability assessment of global change impacts. Participating stakeholders were primarily ecosystem managers and policy advisers interested in potential impacts on ‘Agriculture’, ‘Forestry’, ‘Water’, ‘Carbon storage’, ‘Biodiversity’ and ‘Mountain environments’ sectors. First, stakeholder dialogue approaches to integrated assessment are introduced. Methodological considerations on stakeholder selection and dialogue implementation and evaluation follow. The dialogue content and process are evaluated from the perspectives of stakeholders and scientists. Its usefulness in the research process and the relevance of outcomes for stakeholders are particularly considered. The challenging compromises required to perform innovative research, which seeks to achieve both peer scientific credibility and societal relevance, are emphasized. Effective stakeholder dialogues play a substantial role in raising the visibility and meaningfulness of vulnerability assessments as critical means to improve awareness on global change and its potential worrying impacts on society. They further provide scientists with critical information on ecosystem management and sectoral adaptive capacity. These processes of mutual learning and knowledge exchange moreover foster a better understanding of the potential and limits of global change modelling and vulnerability assessment for policy and ecosystem management.

Using critical systems thinking to foster an integrated approach to sustainability: a proposal for development practitioners

Throughout the development sector, there is increasing recognition of links between the environment and aspects of development such as poverty alleviation, health, income generation, and agriculture. While furnished with a diverse range of perspectives and approaches, development practice is in need of ways to better conceptualize the interactions between the social, environmental, and economic dimensions of sustainability so that opportunities for simultaneous improvement in human and ecological well-being can be identified more readily. Critical systems thinking is proposed as a way for development practitioners to conceptualize and act toward the integration of these economic, social, and environmental dimensions and, in so doing, support communities to nurture both human and ecosystem well-being. Four desirable attributes of a critical systems thinking approach to development are identified based on development literature, critical systems literature, and the author’s research into sustainability in semi-rural communities in Vietnam. The four attributes are ‘a systems thinking approach;’ ‘an ethical base to action and choices;’ ‘critical reflection permeates processes;’ and ‘appreciation of diverse views and application of diverse approaches.’ These attributes are described and then offered as the basis for further discussion of the ways in which simultaneous improvement of human well-being and ecosystem health can become an integral part of development practice.     

Perceptions toward stewardship among residents living near U.S. Department of Energy Nuclear Facilities

Although stewardship has been widely defined and used in environmental management and planning, there is a dearth of studies that describe how the lay public perceives this concept. A national sample of residents in 14 states who live near DOE nuclear facilities were interviewed to delineate public understanding and awareness of the stewardship program of the U.S. Department of Energy (DOE). This study discusses the findings of the survey and discusses how institutional trust influences public participation and resident’s choices of potential stewards. Almost 40% of the respondents could not define stewardship; those who did, believed that ‘responsibility,’ ‘management,’ and ‘accountability’ are key elements of stewardship. In addition, about a third of the respondents identified Federal groups and the DOE as potential stewards. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue