Global warming and population change both heighten future risk of human displacement due to river floods

Every year, millions of people around the world are being displaced from their homes due to climate-related disasters. River flooding is responsible for a large part of this displacement. Previous studies have shown that river flood risk is expected to change as a result of global warming and its effects on the hydrological cycle. At the same time, future scenarios of socio-economic development imply substantial population increases in many of the areas that presently experience disaster-induced displacement. Here we show that both global warming and population change are projected to lead to substantial increases in flood-induced displacement risk over the coming decades. We use a global climate-hydrology-inundation modelling chain, including multiple alternative climate and hydrological models, to quantify the effect of global warming on displacement risk assuming either current or projected future population distributions. Keeping population fixed at present levels, we find roughly a 50% increase in global displacement risk for every degree of global warming. Adding projected population changes further exacerbates these increases globally and in most world regions, with the relative global flood displacement risk is increasing by roughly 350% at the end of the 21st century, compared to an increase of 150% without the contribution of population change. While the resolution of the global models is limited, the effect of global warming is robust across greenhouse gas concentration scenarios, climate models and hydrological models. These findings indicate a need for rapid action on both climate mitigation and adaptation agendas in order to reduce future risks to vulnerable populations

Socio-economic consequences of post-disaster reconstruction in hazard-exposed areas

With coastal populations growing and sea levels rising, reconstruction decisions after coastal disasters are increasingly consequential determinants of future societal vulnerability and thus the sustainability of development. The humanitarian sector tends to favour rebuilding in-place to avoid the social disruptions of mass relocation, yet evidence on what affected people want is mixed. Using the case of post-tsunami Banda Aceh, Indonesia, we investigate whether a policy to rebuild in-place in the disaster-affected area suits an urban population that was previously unaware of the hazard. We show that following the tsunami, a substantial proportion of the population prefers to live farther from the coast. This has caused a new price premium for inland properties and socio-economic sorting of poorer households into coastal areas. These findings show that offering reconstruction aid predominantly within a hazard-exposed area can inadvertently transfer disaster risk to the poor.NRF (Natl Research Foundation, S’pore)MOE (Min. of Education, S’pore

Trust and distrust of tsunami vertical evacuation buildings: Extending protection motivation theory to examine choices under social influence

Tsunami vertical evacuation (TVE) buildings have the potential to save many lives. Yet whether TVE buildings actually save lives depends critically on whether people trust and evacuate to them, a question that has not previously been researched. We examine the case of the city of Banda Aceh, Indonesia, where a M8.6 earthquake on 11-April-2012 caused a spontaneous mass evacuation but no tsunami. Our survey of residents living near TVE buildings (n = 202) shows that they clearly prefer horizontal evacuation: in the 2012 earthquake, only 26% evacuated to a TVE building, while 74% evacuated horizontally; if a similar earthquake happened in the future, only 32% intend to evacuate to a TVE building, while 68% intend to evacuate horizontally. To investigate the reasons for this, we extend protection motivation theory to examine people's choices among protective actions under social influence. Those who prefer to evacuate horizontally do not trust the safety of the TVE building and think they can reach a safe inland destination in time, while those who prefer to evacuate to a TVE building think they cannot reach a safe inland destination in time. Encouragement from friends and family influences people's evacuation destinations but official information and training do not. These findings suggest that more attention to the social context is crucial for the effectiveness of TVE buildings. Our extension of protection motivation theory to include choices among protective actions under social influence can be broadly useful in research on self-protective behavior in natural hazards, public health, and other contexts.NRF (Natl Research Foundation, S’pore)MOE (Min. of Education, S’pore)Published versio

A data-driven approach to rapidly estimate recovery potential to go beyond building damage after disasters

Following a disaster, crucial decisions about recovery resources often prioritize immediate damage, partly due to a lack of detailed information on who will struggle to recover in the long term. Here, we develop a data-driven approach to provide rapid estimates of non-recovery, or areas with the potential to fall behind during recovery, by relating surveyed data on recovery progress with data that would be readily available in most countries. We demonstrate this approach for one dimension of recovery—housing reconstruction—analyzing data collected five years after the 2015 Nepal earthquake to identify a range of ongoing social and environmental vulnerabilities related to non-recovery in Nepal. If such information were available in 2015, it would have exposed regional differences in recovery potential due to these vulnerabilities. More generally, moving beyond damage data by estimating non-recovery focuses attention on those most vulnerable sooner after a disaster to better support holistic and nuanced decisions.ISSN:2662-443

Rebuilding historic urban neighborhoods after disasters: Balancing disaster risk reduction and heritage conservation after the 2015 earthquakes in Nepal

The 2015 Nepal earthquakes devastated the Kathmandu Valley and exposed the challenges of conserving andrestoring architectural heritage in historic urban neighborhoods damaged by disasters, while also trying to rapidly rebuild houses, revitalize livelihoods, and reduce vulnerabilities to future hazards. In this paper we use quantitative and qualitative data to investigate how traditional housing was transformed during the post-earthquake reconstruction of four historic neighborhoods in the Kathmandu Valley. We assess how traditional housing stock in these neighborhoods was transformed by a combination of the direct impact of the earthquake; the enforcement of seismic-resistant modern building technology; the costs and logistics of rebuilding; and the priorities of local residents. Our findings indicate that the enforcement of seismic safety building codes and the expense of incorporating traditional architectural elements led to notable changes to the tangible cultural heritage of Kathmandu's historic urban neighborhoods, but likely also improved seismic safety.ISSN:2212-420

Remarriage strategies for post-disaster widows and widowers following the 2004 Indian Ocean tsunami in Aceh, Indonesia

The 2004 Indian Ocean tsunami caused extensive loss of life and disrupted family units, leaving large numbers of widows, widowers, and orphans. While it is common to identify disaster widows and orphans as potentially vulnerable groups, there has been limited research about how families are reconstructed after a major disaster. The main objective of this paper is to better understand what factors motivate persons who lost a spouse in a disaster to either re-marry or stay single. We use quantitative data from a statistically representative survey of tsunami-affected households in the Banda Aceh, Aceh Besar, and Aceh Jaya districts in the Aceh province of Indonesia conducted a decade after the tsunami to show that 18% of households reported the death of a spouse during the tsunami. Out of these, 66% of widows/widowers reported marrying again within a decade after the tsunami, with most remarried within the first three years after the disaster. We use qualitative data from in-depth interviews with 36 widows and widowers to identify motivations behind the decision to remarry or stay single. We found that widows were most likely to get remarried to provide economic security, support for their surviving children, and because of concerns about their reputation if they were unmarried. Widowers were more likely to remarry to secure domestic support and caregiving for themselves as they got older and to help them care for their surviving children. Some widows and widowers decided not to remarry because of concerns about assuming additional financial liabilities, distressing their surviving children, and (for women) giving up personal freedoms. Our research on the re-marriage decisions of tsunami widows and widowers shows that very personal decisions about family should be seen within the framework of household and community resilience

Rethinking relief, reconstruction and development: Evaluating the effectiveness and sustainability of post-disaster livelihood aid

This paper presents a field study on the long-term effectiveness and sustainability of livelihood interventions following the 2004 Indian Ocean tsunami in Aceh, Indonesia. We assess the extent to which post-tsunami aid in Aceh helped beneficiaries to stabilize and restore their pre-disaster livelihoods, and/or develop new livelihoods. We draw upon qualitative data captured in 183 in-depth interviews and 38 focus group discussions involving village leaders, livelihood aid participants, and NGO workers. Our results show that livelihood assistance helped people stabilize their household finances and partially restore their pre-disaster livelihoods. Furthermore, we found that aid programs were able to help some people without pre-disaster livelihood experience to participate in part-time, ad hoc work. However, aid packages were generally not able to support the development of full-time, sustainable new livelihoods for people lacking pre-disaster training and experience. Our data suggests that it is difficult to conduct efficient and sustainable livelihood development initiatives within the time pressures and current institutional approaches to large-scale post-disaster reconstruction.ISSN:2212-420

Social capital and community integration in post-disaster relocation settlements after the 2004 Indian Ocean Tsunami in Indonesia

The permanent relocation of persons from areas threatened by environmental stress is widely seen within the international humanitarian sector as problematic due to negative social and economic impacts. However, relocation is increasingly seen as a likely, if unfortunate, response to climate change as rising sea-levels, changing ecological conditions, and increasingly intense disasters create powerful push factors. The more dramatic examples of environmental migration focus on long-distance movements, including crossing national borders, which raise issues about the importance of social capital for migrants trying to build community cohesion and integrate into different cultural contexts. However, it is likely that most relocation because of environment stress will occur at sub-national to very local geographic scales, similar to what happens after large-scale disasters, meaning that persons might be resettled within familiar cultural, linguistic, and religious contexts. In this paper we use qualitative data collected in 12 resettlement complexes built in Aceh, Indonesia for persons displaced by the 2004 Indian Ocean Tsunami to analyze the importance of social capital for building cohesion within resettlement complexes and between resettlement complexes and host communities. We find that even though tsunami-affected persons were generally relocated less than 20 km from their pre-tsunami homes, there were clear social distinctions between resettled persons and host communities, which had practical impacts on integration, access to resources, and participation within local governance structures. We found shared cultural and religious traditions and social practices served as important sources of bonding capital within resettlement complexes. However, the same attributes were less effective as bridging capital between resettlement complexes and their host communities. These findings show that governments and NGOs need to be cautious about underestimating the negative social disruptions caused by short-distance relocation and the importance of bonding social capital for fostering stable and sustainable resettlement communities.ISSN:2212-420

Uncertainty and sensitivity analysis for probabilistic weather and climate-risk modelling: an implementation in CLIMADA v.3.1.0

Modelling the risk of natural hazards for society, ecosystems, and the economy is subject to strong uncertainties, even more so in the context of a changing climate, evolving societies, growing economies, and declining ecosystems. Here, we present a new feature of the climate-risk modelling platform CLIMADA (CLIMate ADAptation), which allows us to carry out global uncertainty and sensitivity analysis. CLIMADA underpins the Economics of Climate Adaptation (ECA) methodology which provides decision-makers with a fact base to understand the impact of weather and climate on their economies, communities, and ecosystems, including the appraisal of bespoke adaptation options today and in future. We apply the new feature to an ECA analysis of risk from tropical cyclone storm surge to people in Vietnam to showcase the comprehensive treatment of uncertainty and sensitivity of the model outputs, such as the spatial distribution of risk exceedance probabilities or the benefits of different adaptation options. We argue that broader application of uncertainty and sensitivity analysis will enhance transparency and intercomparison of studies among climate-risk modellers and help focus future research. For decision-makers and other users of climate-risk modelling, uncertainty and sensitivity analysis has the potential to lead to better-informed decisions on climate adaptation. Beyond provision of uncertainty quantification, the presented approach does contextualize risk assessment and options appraisal, and might be used to inform the development of storylines and climate adaptation narratives.ISSN:1991-9603ISSN:1991-959