Determinants of risk: Exposure and vulnerability

Many climate change adaptation efforts aim to address the implications of potential changes in the frequency, intensity, and duration of weather and climate events that affect the risk of extreme impacts on human society. That risk is determined not only by the climate and weather events (the hazards) but also by the exposure and vulnerability to these hazards. Therefore, effective adaptation and disaster risk management strategies and practices also depend on a rigorous understanding of the dimensions of exposure and vulnerability, as well as a proper assessment of changes in those dimensions. This chapter aims to provide that understanding and assessment, by further detailing the determinants of risk as presented in Chapter 1. The first sections of this chapter elucidate the concepts that are needed to define and understand risk, and show that risk originates from a combination of social processes and their interaction with the environment (Sections 2.2 and 2.3), and highlight the role of coping and adaptive capacities (Section 2.4). The following section (2.5) describes the different dimensions of vulnerability and exposure as well as trends therein. Given that exposure and vulnerability are highly context-specific, this section is by definition limited to a general overview (a more quantitative perspective on trends is provided in Chapter 4). A methodological discussion (Section 2.6) of approaches to identify and assess risk provides indications of how the dimensions of exposure and vulnerability can be explored in specific contexts, such as adaptation planning, and the central role of risk perception and risk communication. The chapter concludes with a cross-cutting discussion of risk accumulation and the nature of disasters

Constraints on the nature of dust particles by infrared observations

The far-infrared (FIR) emissivity of dust is an important parameter characterizing the physical properties of the grains. With the availability of stellar databases and far-infrared data from Infrared Space Observatory (ISO) it is possible to compare the optical and infrared properties of dust, and derive the far-infrared emissivity with respect to the optical extinction. In this paper we present the results of a systematic analysis of the FIR emissivity of interstellar clouds observed with ISOPHOT (the photometer onboard ISO) at least at two infrared wavelengths, one close to ~100um and one at 200um. We constructed FIR emission maps, determined dust temperatures, created extinction maps using 2MASS survey data, and calculated far-infrared emissivity for each of these clouds. We present the largest homogeneously reduced database constructed so far for this purpose. During the data analysis special care was taken on possible systematic errors. We find that far-infrared emissivity has a clear dependence on temperature. The emissivity is enhanced by a factor of usually less than 2 in the low dust temperature regime of 12K<=T_d<=14K. This result suggests larger grain sizes in those regions. However, the emissivity increase of typically below 2 restricts the possible grain growth processes to ice-mantle formation and coagulation of silicate grains, and excludes the coagulation of carbonaceous particles on the scales of the regions we investigated. In the temperature range 14K<=T_d<=16K a systematic decrease of emissivity is observed with respect to the values of the diffuse interstellar matter. Possible scenarios for this behaviour are discussed in the paper.Comment: Accepted for publication in MNRA

Mapping temporally-variable exposure to flooding in small Mediterranean basins using land-use indicators

This article deals with mapping exposure (or external vulnerability) to flood risk in two typical Mediterranean ephemeral streams: the Barranco de Carraixet and the Rambla de Poyo. The floodplains of both streams are within the metropolitan area of the city of Valencia (Spain"s third largest city). Following the Mediterranean model, they are very fertile areas (with intense periurban and highly productive agriculture) which have recently absorbed the great urban expansion of the metropolis. Hydrologically these basins remain dry for most of the year, but become particularly dangerous during flash-flood events. They generate a risk pattern highly dependent on exposure since, in general, the hazard factor is very difficult to map, given the unpredictable nature of flash-floods. This work constitutes a proof of concept based on simple estimators obtained from land uses. External vulnerability or exposure is evaluated as a function of economic land value and human exposure to hazard. Land value is directly taken from the cadastre whilst human exposure is indirectly estimated from the location of population in relation to timeeactivity profiles. The temporal dimension is introduced and three exposure scenarios have been mapped, related to different time periods: working days, nights, weekends and holidays. The results show different patterns of exposure for each plain. In Carraixet floodplain exposure is greater at night and on weekends and holidays than during working hours, on account of the dominant agricultural and residential land uses. In the Poyo plain there are no major contrasts in absolute terms between day and night time, although spatial patterns of exposure vary from day to night: during the day, exposure is higher in industrial and commercial areas (around communication routes) whilst at night residential areas show more exposure

"Last-Mile" preparation for a potential disaster

Extreme natural events, like e.g. tsunamis or earthquakes, regularly lead to catastrophes with dramatic consequences. In recent years natural disasters caused hundreds of thousands of deaths, destruction of infrastructure, disruption of economic activity and loss of billions of dollars worth of property and thus revealed considerable deficits hindering their effective management: Needs for stakeholders, decision-makers as well as for persons concerned include systematic risk identification and evaluation, a way to assess countermeasures, awareness raising and decision support systems to be employed before, during and after crisis situations. The overall goal of this study focuses on interdisciplinary integration of various scientific disciplines to contribute to a tsunami early warning information system. In comparison to most studies our focus is on high-end geometric and thematic analysis to meet the requirements of small-scale, heterogeneous and complex coastal urban systems. Data, methods and results from engineering, remote sensing and social sciences are interlinked and provide comprehensive information for disaster risk assessment, management and reduction. In detail, we combine inundation modeling, urban morphology analysis, population assessment, socio-economic analysis of the population and evacuation modeling. The interdisciplinary results eventually lead to recommendations for mitigation strategies in the fields of spatial planning or coping capacity

Framing vulnerability, risk and societal responses: the MOVE framework

The paper deals with the development of a general as well as integrative and holistic framework to systematize and assess vulnerability, risk and adaptation. The framework is a thinking tool meant as a heuristic that outlines key factors and different dimensions that need to be addressed when assessing vulnerability in the context of natural hazards and climate change. The approach underlines that the key factors of such a common framework are related to the exposure of a society or system to a hazard or stressor, the susceptibility of the system or community exposed, and its resilience and adaptive capacity. Additionally, it underlines the necessity to consider key factors and multiple thematic dimensions when assessing vulnerability in the context of natural and socio-natural hazards. In this regard, it shows key linkages between the different concepts used within the disaster risk management (DRM) and climate change adaptation (CCA) research. Further, it helps to illustrate the strong relationships between different concepts used in DRM and CCA. The framework is also a tool for communicating complexity and stresses the need for societal change in order to reduce risk and to promote adaptation. With regard to this, the policy relevance of the framework and first results of its application are outlined. Overall, the framework presented enhances the discussion on how to frame and link vulnerability, disaster risk, risk management and adaptation concepts

Flood risk assessment and mapping in peri-urban Mediterranean environments using hydrogeomorphology. Application to ephemeral streams in the Valencia region (eastern Spain)

This paper proposes a methodology for mapping flood risk in ephemeral streams, based on assessing flood hazards and global exposure. The method has been applied to the peri-urban area of Valencia, extended over the floodplains of the Barranco del Carraixet and Rambla de Poyo catchments. Hazard was assessed using hydrogeomorphological methods. Global exposure was estimated as a combination between the economic value of land use and human exposure, following a previous study carried out by Camarasa, A.M., López, M.J. and Soriano, J., 2011. Mapping temporally variable exposure to flooding in small Mediterranean basins using land-use indicators, Applied Geography 31 (19), 136¿145. Synthesis mapping was elaborated to spatially rank flood risks, in terms of their hazard and exposure components. The method is simple, effective and easily comparable. The results reveal diverse risk configurations for each floodplain, even though both are in the vicinity of Valencia city (metropolitan area). This flood risk mapping method is very useful for land use planning because it enables swift diagnosis of the nature of risks and can supports decision making by risk managers and urban planners

JWST/NIRSpec Observations of the Planetary Mass Companion TWA 27B

We present 1-5um spectroscopy of the young planetary mass companion TWA 27B (2M1207B) performed with NIRSpec on board the James Webb Space Telescope. In these data, the fundamental band of CH_4 is absent and the fundamental band of CO is weak. The nondetection of CH_4 reinforces a previously observed trend of weaker CH_4 with younger ages among L dwarfs, which has been attributed to enhanced non-equilibrium chemistry among young objects. The weakness of CO may reflect an additional atmospheric property that varies with age, such as the temperature gradient or cloud thickness. We are able to reproduce the broad shape of the spectrum with an ATMO cloudless model that has T=1300 K, non-equilibrium chemistry, and a temperature gradient reduction caused by fingering convection. However, the fundamental bands of CH_4 and CO are somewhat stronger in the model. In addition, the model temperature of 1300 K is higher than expected from evolutionary models given the luminosity and age of TWA 27B (T=1200 K). Previous models of young L-type objects suggest that the inclusion of clouds could potentially resolve these issues; it remains to be seen whether cloudy models can provide a good fit to the 1-5um data from NIRSpec. TWA 27B exhibits emission in Paschen transitions and the He I triplet at 1.083um, which are signatures of accretion that provide the first evidence of a circumstellar disk. We have used the NIRSpec data to estimate the bolometric luminosity of TWA 27B (log L/L_sun=-4.466+/-0.014), which implies a mass of 5-6 MJup according to evolutionary models.Comment: Astrophysical Journal Letters, in pres