IPCC Framework Research Articles

Livelihood Vulnerability to Climate Change of Casava Smallholders in Central Highlands of Vietnam

This study utilized the Livelihood Vulnerability Index (LVI) within the IPCC framework (LVI-IPCC) for cassava farming households in the central highlands of Vietnam. Data were gathered from a household survey (364 households) in Krong Bong and Ea Kar districts, Dak Lak province, in-depth interviews (22 key informants) and two focus group discussions. By analyzing variations in LVI components and conducting a Poisson regression analysis, the results revealed that cassava farming households in the studied areas exhibited moderate vulnerability to climate change and variability. Variations in vulnerability levels were observed between the two districts, with disparities found across sensitivity, exposure, and adaptive capacity. Differences in LVI were also evident between the Kinh and ethnic minority groups and between the poor and non-poor farming households, primarily attributable to variations in adaptive capacity. Key determinants of household livelihood vulnerability included the intensity of climate risks, the frequency of extreme climate events, market risks, environmental shocks, land slope, land area at risk of flooding, climate change knowledge, transportation means, market linkages, access to credit, and income diversification. The study further proposed strategies for local authorities and relevant agencies to enhance climate change resilience among cassava farming households.

Livelihood vulnerability assessment among the agrarian indigenous communities of Sundarban Biosphere Reserve in India for building resilience and adaptation.

Indian Sundarban Biosphere Reserve (ISBR) is a vulnerable Southeast Asian region. The negative effects of climate change were putting tremendous pressure on this region. However, a dearth of literature focused on the vulnerability and adaptation to climate change among the tribal agrarian community in ISBR. Against this backdrop, this study aims to ascertain different tribal community's perceptions of vulnerability and adaptation preferences through a mixed-method approach and measure the determinants of agricultural livelihood vulnerability. Using a multi-stage random sampling technique and with the help of a pre-structured survey schedule in ISBR, this study involved 300 randomly selected respondents in the interview and focus group discussion. This study applied the IPCC framework to evaluate the integrated livelihood vulnerability to climate change in the ISBR. This study measured the determinant factors underlying vulnerability using ordered probit regression and focus group discussions. This study measures vulnerability as a function of adaptive capacity, sensitivity, and exposure. For the integrated livelihood vulnerability index, 44 indicators under 9 main categories were chosen. 36.52% of rural livelihoods in the southern and southeastern part of Indian SBR were highly vulnerable due to high exposure to flood, riverbank erosion, frequent cyclone, high sensitivity to inadequate access to basic amenities, and low adaptive capacities due to poor livelihood security and poor socio-economic condition. On the other hand, the northern portion of the region exhibits low to moderate vulnerability because of low exposure, low sensitivity, and strong adaptive capacity. Results suggest that the limited adaptation capacities of the tribal household, such as inadequate infrastructure and low-income opportunities, are the primary reasons for livelihood vulnerabilities. This approach can be applied at different scales in other regions of India and other developing countries.

Climate change ecological vulnerability and hotspot analysis of himalayan forests in North-Eastern region, India

The Himalayan forests are vulnerable to climate change leading to disturb the current flow of critical ecosystem services to the dependent population. Present study attempts to evaluate the current vulnerability status of major forest types in Nagaland, India due to climate change along with identifying the hot spots for mitigating the vulnerability of the forests. Vulnerability of mixed moist deciduous, pine, wet hill and wet temperate forests were evaluated using the IPCC framework. Local Moran's I analysis, hot spot analysis and a histogram analysis of the vulnerability were made in QGIS. Field data such as Shannon-Wiener Index and Importance Value Index along with secondary data such as edaphic factors, vegetation factors and climatic variables were used for vulnerability analysis. Analysis results that mixed moist deciduous forests had the highest area in under high-high clusters, hot spots and was highly vulnerable. The result suggests that very dense or moderately dense forest cover were less vulnerable than low density forests in the region. The study provides baseline information along with identification of vulnerable hot spot forests for future climate change policy and management of resources at the division level. The study suggests strengthening the less dense forests along with increasing the biodiversity through suitable strategy for mitigating the vulnerability.

Livelihood vulnerability to climate change health impacts among Amhara Sayint district community, northeastern Ethiopia: A composite index approach

Climate change significantly impacts public health, affecting nearly everyone across the globe and contributing to approximately 10% of global mortality. Ethiopia is particularly vulnerable to the changing climate attributed impacts due to economic, and social determinants. While research on climate change is expanding, it often prioritizes its effects on agriculture. The impacts from public health perspective are frequently overlooked. We address this shortcoming by evaluating the vulnerability of the community in the district of Amhara Sayint, Amhara, northeastern Ethiopia, to the health impacts of climate change, and identifying factors involved. Data was collected using a community-based cross-sectional approach, involving 605 randomly selected households between July Twenty and September Five, 2022. The data collection process utilized a validated and pilot-tested questionnaire, which was administered through face-to-face interview with the aid of Kobo Collect toolbox. The community's vulnerability was assessed using the IPCC's framework of vulnerability. Household's Vulnerability status was then classified into three levels according to their Livelihood Vulnerability Index (LVI) score. A partial proportional oddsapproach of ordinal logistic regression model was used to identify factors associated with vulnerability to climate change attributed health impacts. Among the 605 respondents, 48% (95% CI: 44.1, 52.1) were identified as vulnerable, and about 4.6 % (95% CI: 3, 6.6) were classified as highly vulnerable. Wealth status (AOR1 = 1.8; 95 % CI: 1.2, 2.8), educational status (AOR1 = 2.8; 95% CI: 1.1, 7.3), marital status (AOR2 = 4.7, 95% CI: 1.6, 13.4), and home crowdedness (AOR2 = 2.9, 95% CI: 1.1, 8.1) significantly associated with vulnerability. Over half of the residents in the district wereeither being vulnerable or highly vulnerable to climate change attributed health impacts. Therefore, prioritizing prevention and preparedness along with conducting spatial analysis to identify high-risk areas for timely intervention, is essential.

Risk assessment of the jhumias in eastern Himalayan region: An IPCC framework approach

Climate change is intricately linked with amplifying existing risk across multiple sectors, and assessment of the indigenous farmers practising jhum (jhumias) is highly necessary for developing adaptation strategies in the biogeographically-diverse northeast Himalayan region. The current study estimates the Shared Socio-Economic Pathway 2 (SSP2) – 4.5 hazard scenario for the year 2040–2059 using Coupled Model Inter-comparison Project 6 (CIMP6) (mean projection) and Multi-Model Ensemble. The remaining risk dimensions (exposure and vulnerability) were derived from household survey data involving 450 households from 18 villages representing six districts, three states, and four watershed basins. This framework used an indicator approach for defining risk dimensions and a spatial approach for the final risk presentation and classification. Principal Component Analysis (PCA) was used to select and group the indicators. All chosen indicators underwent varimax rotation, and factors with eigenvalues greater than one were considered for grouping into components. Different weights for each indicator were defined using the Shanon entropy method. Climate change risk was found to be highest in Khudengthabi village in Chandel district, followed by Sangshak village in Ukhrul district. Lack of land ownership, low yield, no alternative livelihood option, an insufficient market, and unavailability of labour force are some of the major factors contributing to higher risk in the area. The study recommends skill development and alternative livelihood programmes with a new education policy that encourages the dropout youth to continue in schools and colleges. Subsequent policy initiatives should prioritize villages, indicators and components with high index scores to optimize resource allocation and facilitate quicker adaptation.

From perils to preparedness: Decoding coastal hazard risks on Kerala’s central coast through the IPCC framework

From perils to preparedness: Decoding coastal hazard risks on Kerala’s central coast through the IPCC framework

Examining the links between household livelihood resilience and vulnerability: disaster resettlement experience from rural China

Livelihood status of rural households is the focus of disaster resettlement research. Influenced by various factors, rural households face multiple environmental and social pressures after relocation, and the study of livelihood resilience and vulnerability provides a new framework for research into the livelihoods of relocated households. There has been a call for more quantitative evidence about the links between livelihood resilience and livelihood vulnerability in the context of disaster resettlement. This study uses data from a sample of 657 individuals from the relocation area of Ankang prefecture in southern Shaanxi, China. The resilience of rural household livelihood systems is quantified in terms of two dimensions of general resilience and specific resilience using the spatial vector method from systems engineering. The IPCC framework was used to measure three dimensions of livelihood vulnerability: exposure, sensitivity, and adaptability, and a threshold regression model was applied to investigate the impacts of livelihood resilience on livelihood vulnerability. Results show that: (i) livelihood vulnerability of relocated households (−0.042) was significantly lower than that of local households (0.091), while relocated households in the process of livelihood reconstruction had a certain degree of vulnerability risk. (ii) there is a significant threshold effect of livelihood resilience on livelihood vulnerability of rural households. (iii) increasing livelihood resilience significantly reduced the degree of vulnerability of rural households, and the marginal effect of general resilience on livelihood vulnerability shows a decreasing trend. Specific resilience has a positive influence on livelihood vulnerability before it exceeds the threshold, but the effect disappears above the threshold of resilience. (iv) The threshold value of livelihood resilience of local households (0.5039) is generally lower than that of relocated households (0.6548), and relocation does improve the ability of rural households to resist uncertainty risks. It is necessary for local governments to formulate more targeted policies to reduce the livelihood vulnerability of rural households and thereby promote sustainable livelihood development.

Uncertainty and climate change: The IPCC approach vs decision theory

Uncertainty is one of the most important challenges in the study of climate change and its interactions with the economy. This paper looks at this uncertainty from two different points of view. The first one is the way in which the IPCC deals with uncertainty in its reports, and the way in which that uncertainty is communicated. The IPCC approach is implemented using a combination of quantitative and qualitative methods as well as heuristics. The IPCC studies climate change, its evolution, and its impact in a context which, in terms of the decision-making approach, is akin to analysis under risk. The second point of view is the one adopted by decision theory, which deals with uncertainty in the Knightian sense and, more specifically, with uncertainty that is manifested in multiple probabilistic models or priors. The presence of multiple priors is associated with ambiguity aversion and misspecification concerns that necessitate the use of maxmin optimizing approaches. The IPCC and the decision theory approaches are briefly reviewed and compared, with the objective of finding ways to accommodate the concept of risky parameters or impacts of the IPCC framework within the framework of optimization under uncertainty in multiple probabilistic models.

Study on emission factor and reduction potential of organic solid waste gasification process

This paper conducts an in-depth study on the gasification treatment of Organic Solid Waste (OSW) and its carbon emissions, intending to fill the gap in the existing literature regarding the calculation methods for carbon emissions from OSW gasification. The study establishes a methodology for calculating carbon emission factors during the OSW gasification process and explores the potential for negative carbon emissions. For this purpose, indicator including the Carbon Dioxide Equivalent Warming Number (CEWN) is used to assess the greenhouse gas emissions of the gasification process by calculating carbon emission factors under different gasification conditions. It is found that within a certain range, increasing the gasification temperature, Equivalence Ratio (ER), and Steam to Biomass ratio (S/B) can positively influences the achievement of negative carbon emissions. These findings hold significant implications for optimizing the OSW gasification process, reducing carbon emissions, and ultimately achieving carbon neutrality. Furthermore, this study fills a critical void in the gasification field within the IPCC framework and offers essential guidance for promoting to achieve peak carbon emissions in the gasification industry and accelerating the goal of carbon neutrality.

Identification of functional traits responsible for environmental vulnerability of Cedrus deodara in temperate forests of Western Himalaya

Climate change is impacting forest tree species adversely and making the ecological system vulnerable. The present study attempts to assess the internal vulnerability of Cedrus deodara occurring in nine sub-types of temperate forests in Western Himalaya, India via a plant functional trait-based approach. Internal vulnerability was assessed based on sensitivity and adaptive capacity through proposing an index using IPCC framework. Sensitivity was determined based on various traits (indicators) of light harvesting, carbon assimilation, nutrient content, and water budget, whereas adaptability was defined based on light harvesting efficiency, water use efficiency, resource use efficiency, and nutrient limitation. Sensitivity was maximum in Dry Deodar Forest (0.51) and Low-Level Blue Pine Forest (0.51) and minimum in Western Mixed Coniferous Forest (o.38), however adaptability was maximum in Kharsu Oak Forest (0.65) and Moist Deodar Forest-II (0.65) with minimum adaptability for Ban Oak Forest (0.53). In Ban Oak Forest, Low-Level Blue Pine Forest and Moist Deodar Forest-II high stomatal conductance compensates the low chlorophyll achieving homeostasis state for photosynthesis. Negative minimum temperature (-6.95 to −2.04 °C) in winters followed by high monsoon rainfall (417.74 to 1256.13 mm) causes high sensitivity amongst the C. deodara population in Low Level Blue Pine Forest, Dry Deodar Forest and Moist Deodar Forest-II; and adaptability was majorly affected by water availability i.e., excessive monsoon rainfall in Ban Oak Forest (1962.45 mm) and least rainfall in Neoza Pine Forest (349.50 mm). Overall, the vulnerability was high in Low Level Blue Pine Forest (0.46), Ban Oak Forest (0.45) and Dry Deodar Forest (0.45). Present study identified key traits for species vulnerability therefore management intervention should orient towards those silvicultural operations which may reduce relative water use of the species and may also facilitate for improved photosynthesis i.e., through water provision and density management of the C. deodara dominated forests in Himalayan region. The study concludes that a unified approach for managing species of the forest may be disadvantageous and detrimental to forest conservation. Rather site-specific management approach, which led to incremental response to the identified traits may support the conservation of species.

Assessing the Livelihood Vulnerability to Impact of Climate Change in Western Bhutan

Climate change possesses vagaries threats to the subsequent livelihood of the people in Bhutan and it is crucial to enhance adaptive capacity. Therefore, building resiliency requires information on vulnerability of the system of interest. Therefore, this study assessed smallholder farmer’s vulnerability to impacts of climate change and variability in western parts (Punakha, Wangdue, Gasa) of Bhutan. A survey was conducted from 392 randomly selected households based on major components of sociodemographic profiles, livelihood strategies, health, social network, food, water and natural disaster and climate variability. Data was analyzed using Livelihood Vulnerability Index approach (LVI) and IPCC framework approach (LVI-IPCC). The result indicated that the LVI (range 0.39 to 0.43) and LVI-IPCC (range -0.018 to 0.030) varied across the districts. Punakha district (0.43) was most vulnerable by the LVI approach, whereas Gasa district (0.03) revealed as most vulnerable using LVI-IPCC approach. The rate of vulnerability in a district varied according to their degree of exposure and adaptive capacity to the impacts of climate change among smallholder farmers. Higher exposure to climatic extremes, dependency on natural resources and weak social networking were recognized as components that determine vulnerability. The results are expected to serve an indication to design appropriate intervention to cope with climate change impacts and increase resiliency for sustainable livelihood.

Assessing the Livelihood Vulnerability of Herders to Changing Climate in Chui Oblast, Kyrgyz Republic

Kyrgyzstan is a country that is heavily reliant on agricultural products and animal husbandry, making it particularly vulnerable to the effects of climate change. Using the livelihood vulnerability index (LVI), this study attempted to assess vulnerability to climate change impacts on land, biodiversity, herders, and livestock in Kyrgyzstan’s mountainous areas. The survey was conducted using respondent interviews. In the Chon-Kemin valley target area, we interviewed 198 nomad households with livestock. The study found that communities rely heavily on pasture resources, that there are almost no human–wildlife conflicts (HWCs), and that climate disasters have limited impact. Major components of herders’ sensitivity and adaptive capacity resulted in low numbers. This, combined with rare climate disasters such as droughts and thus low exposure, reduced vulnerability under the IPCC framework. However, any increase in climate disasters, combined with continued land-use pressure, will severely impact herders and their livelihoods. In Kyrgyzstan, hundreds of livestock and dozens of wild animals have already died as a result of late frosts in pastures. National policies and programs should be revised to improve adaptive capacity. This study calls into question the importance of improving wildlife research and capacity building, as well as cooperation between local and national stakeholders.

The livelihood vulnerability and adaptive capacity of shrimp farmers to climate change: a case study in Tra Vinh province, Vietnam

This study calculated the vulnerability and current adaptive capacity of shrimp farmers to climate change in two districts (Duyen Hai –DH and Cau Ngang- CN) of Tra Vinh province, Vietnam. The IPCC framework of vulnerability assessment was employed to analyze three factors (exposure, sensitivity, and adaptive capacity). We proposed 45 indices to calculate those dimensions based on the livelihood capitals (human, physical, natural, social and financial capital). Three methods of assessing climate change vulnerability index were applied to compare the livelihood vulnerability index of shrimp farmers in the two districts (Climate Vulnerability Index – CVI, Livelihood Effect Index-LEI, and Livelihood Vulnerability index under Intergovernmental Panel on Climate Change –LVI-IPCC). Total of 300 households were interviewed in 10 randomly selected villages distributed equally over two districts. The results indicated that three ways of measuring livelihood vulnerability index are consistent with each other. The analysis revealed that the inland district (CN) was more vulnerable to climate change than the coastal districts (DH) due to natural capital and social capital mainly.

Livelihood vulnerability to climate change: Indexes and insights from two ethnic minority communities in Central Vietnam

Ethnic minorities living in secluded regions are usually framed as the most vulnerable to climate change given fragile environments and limited access to resources. Nonetheless, their livelihood vulnerability to climate change has not been adequately assessed, especially in the mountainous areas of central Vietnam. This study thus sought to fill that knowledge gap by applying the livelihood vulnerability index referencing the IPCC framework (LVI-IPCC) to examine the vulnerability of the Pa Co and Co Tu minority communities in upland regions of Thua Thien Hue province, central Vietnam. The results disclosed that the Pa Co tends to be more vulnerable than the Co Tu, mainly due to the higher sensitivity index to natural disasters (p<0.05). In addition, our findings underscored the greater vulnerability of poor or single-parent households. We argued that the livelihood vulnerability of minority households is closely interrelated with poor status, often causing a loop of the poverty trap. Recognizing these, we proposed several managerial recommendations and practical implications to help ethnic minority communities escape such dilemmas while improving their adaptive capacity to climate variability.

Assessment of flood vulnerability of riverine island community using a composite flood vulnerability index

The devastating impact of flooding is gradually increasing worldwide including riverine islands of Bangladesh due to climate change issue. Riverine islands and coastal communities are the primary victims due to their geographical position. The riverine islands (char) of Bangladesh are frequently flooded, necessitating context-specific flood management policies and actions that require an in-depth investigation of household vulnerability level. Therefore, this study assesses the vulnerability level of riverine island dwellers to flooding. Data were collected from 384 household heads living in geographically isolated char areas. A context-specific composite flood vulnerability index was developed under the IPCC framework. The results reveal that all households are vulnerable to flooding and are poorly able to cope with its adverse effect. Households living near the mainland have a somewhat more adaptive capacity than distant households. Flood vulnerability is mainly determined by char households' flood perception, damage, and access to food, water and health resources during flooding. Riverbank erosion, recurrent floods, a lack of employment, and limited access to essential public services were also identified as the primary socio-economic and natural causes of flood vulnerability. To decrease the livelihood risk and promote char dwellers’ resilience, a char-based policy plan with both a short- and a long-term focus is required.

Vegetation Characteristics Based Climate Change Vulnerability Assessment of Temperate Forests of Western Himalaya

Forests are under stress due to variety of climatic and non-climatic factors. Therefore for suitably managing the forests, vulnerability of the forests needs to be understood. The present paper attempts to estimate the vulnerability of various temperate forests of Western Himalaya due to climate change by analyzing the patterns of different taxonomical indices, based on primary data i.e., vegetation data. The paper presents a novel approach for climate change vulnerability assessment based on field data through a bottom-up approach. The vulnerability of the forests was assessed through the IPCC framework by suitably selecting indicators (taxonomy indices and climatic parameters) for the three dimensions of vulnerability i.e., exposure, sensitivity and adaptive capacity. The field data were collected from 17 different temperate forests distributed at the elevation “1600 to 3500 m” in Uttarakhand and Himachal Pradesh, India. Abundance and richness for each forest were collected by randomly laying ten quadrats of size 0.1 ha each. The analysis resulted into identifying the most and the least vulnerable temperate forests of the western Himalaya to climate change. The analysis showed that the Neoza Pine; Moist Deodar; Ban Oak and Dry Broadleaved and Coniferous forest were the most vulnerable forests in the Himalayan temperate forests due to climate change. Moreover, the variation in the levels of the vulnerability status of the selected forests was insignificant with elevational range as well as exposure to climate. The proposed method will serve for vulnerability estimation of forests due to climate change based on the actual realization of the species in the field.

Climate Change Vulnerability Assessment: A Case Study of South West Coastal Community of Bangladesh

This study aimed at assessing the Livelihood Vulnerability Index (LVI) using the IPCC framework approach and a modified approach to estimate climate change vulnerability in south-west coastal area of Bangladesh. Nine Upazillas (sub-districts) in the south west coastal community were considered for this study. The major component indices of LVI such as socio-demographic profile, livelihood strategies, social network, health, food, water, natural disaster and climate variability were calculated based on the household survey data. The LVI based on the IPCC approach (LVI-IPCC) in nine upazillas in southwest coastal region of Bangladesh were found within a range of –0.02 to + 0.04 (on the scale of –1 to +1). In the modified approach, the LVI for the nine study areas was found within a wide range from 0.253 to 0.544 (on a scale of 0 to 1). For the LVI-IPCC approach, although the contributing factors (exposure, sensitivity and adaptive capacity) individually show variations in their indices from one to another, no significant variation is observed for the total livelihood index. However, the modified approach shows significant variation in LVI among the studied nine areas. It is concluded that the modified approach is suitable for community or district level assessment, whereas the LVI-IPCC may be suitable for regional level evaluation.

Assessing Urban Centers’ Vulnerability to Climate Change Using Livelihood Vulnerability Index and Ipcc Framework Model in Southwest Ethiopia

Assessing Urban Centers’ Vulnerability to Climate Change Using Livelihood Vulnerability Index and Ipcc Framework Model in Southwest Ethiopia

COVID-19 in Afghanistan: Evaluating Health Vulnerability and Identifying Controlling Mechanism

Background: The insistent range of coronavirus (COVID-19) crisis and its permeation into least developed countries has escalated the bar of countries fragility and susceptibility. Afghanistan is amongst the most affected countries by the COVID-19 pandemic certainly due to its poor health infrastructure and conflict affected demography. Objective: This study intends to assess the health vulnerability profile and identifying the control mechanism of the north and northeast regions of Afghanistan using the IPCC framework. Method: A pre-evaluated online questionnaire (Google form) and mobile survey of 361 households distributed in 8 provinces across the both zones to collected the primary data. Exposure, sensitivity and adaptive capacity covered the three main components of vulnerability index, weighing method of Iyenger and Sudershan is used to estimate the fabricate vulnerability index. Result: The province’s health vulnerability status was classified to the different groups based on beta distribution. Based on the vulnerability index, 62.5% of provinces were highly vulnerable, 25% moderately and 37.5% were least vulnerable. Conclusion: In north-east region people were highly vulnerable to COVID-19 in terms of sensitivity and exposure, with low copping capacity to cope with COVID-19 pandemic risks compare to the north zone. Recommendation: Enhancing health and hygiene facilities and a handful of lowcost methods such as strengthen informal safety nets and introducing small-scale regional infrastructure projects, could be most cost effective and viable options. Originality: The research work is original and has not been published in other publications. As well, no financial support has been received for the study.

Mapping integrated vulnerability of coastal agricultural livelihood to climate change in Bangladesh: Implications for spatial adaptation planning

Understanding the spatial variation of agricultural livelihood vulnerability to climate change is crucial for developing adaptation strategies in the future, something that has only been seldom done so far in developing economies like Bangladesh. To this end, we developed an integrated vulnerability index (IVI) based on the IPCC framework for analyzing and mapping the vulnerability of agricultural livelihoods in coastal Bangladesh. The IVI was calculated as a function of three components: exposure, sensitivity, and adaptive capacity. We used 45 indicators from nationally comparable and reliable datasets to conduct the research. Besides, a socio-economic livelihood vulnerability index (SELVI) was developed on the basis of sensitivity and adaptive capacity indicators and displayed in a scatter diagram in order to identify the socio-economically more vulnerable districts of coastal Bangladesh. A circumplex chart was used to disaggregate the normalized indices of sensitivity and adaptive capacity components, allowing the researcher to discover the factors that cause and mitigate the vulnerability. Using the IVI information, a vulnerability map was created that revealed that Patuakhali, Noakhali, Bhola, and Barguna districts in the exposed central coastal region were the topmost vulnerable districts, reflecting the fact that the agricultural livelihoods of 7.3 million people were highly vulnerable to the effects of climate change. The geographical diversity in salt intrusion, river-bank erosion, dependence ratio, crop yield, literacy, the density of physicians in the hospital, disaster-resistant houses, shelter facilities, and irrigated farming areas contributed to the diverse coastal agricultural livelihood vulnerability.