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1 INTRODUCTION 2 will be decreased by at least half and Vietnam would be a country without rice exports (Tran Quoc Dat et al., 2012). Threats of food security, depletion of natural resources, shrinking 1. Rationale It is believed that the establishment of livelihood vulnerability index is necessary in order to categorize the vulnerability for each country, region and community. These indices cultivated areas will negatively affect citizens' livelihood... These are great challenges faced by the Mekong Delta when resolving salinity intrusion to improve the socio-economic serve as the basis for direct intervention in the most severely affected areas (Alam, 2017; Bhuiyan et al, 2017; Jacobson et al., 2018). Perch (2011) also agreed as he proved that if adaptation policies (such as national adaptation programme of action ) are developed without considering the livelihoods of vulnerable groups, they are unlikely to succeed. Therefore, many evaluation methods on livelihood vulnerability have been constructed and developed. Among them, Livelihood Vulnerability Index (LVI) proposed by Hahn et al. (2009) has been used by many scholars (Sarker et al., 2019; Zhang and associates, 2019; Peng et al, 2019; Tjoe, 2016; Adu et al., 2018; Huong et al, 2019). However, most of the studies applying LVI used weighted balance, which was criticized as the same weights were applied to different components (Beccari, 2016; Miller et al., 2013; Abeje et al., 2019). Therefore, it is necessary to develop a more suitable calculation method for LVI to produce more convincing results. The development of LVI to classify the vulnerability for each country, region and community is essential, nevertheless most previous studies only calculated the index without considering the overall importance of vulnerable components on livelihood. It is neccessary to provide a general picture of impacts by vulnerable elements (exposure, sensitivity and adaptive capacity) on livelihood as well as study factors that reduce negative effects on vulnerability on livelihood in order to devise effective adaption policies. Therefore, more specialized studies are neccessary in order to have a clearer picture of vulnerable components' influence on livelihood and to take into The necessity of this topic not only originates from the knowledge gap but also from the practical needs. It is found that climate change has adversely affected the world economy through the increased frequency of extreme events such as droughts, floods, storms, and sea level rise (Anik et al., 2018). Although many countries are affected by global climate change, the biggest impact will happen to countries that rely on agricultural production (Mendelsohn, 2008). Vietnam, a rice-based agricultural economy, will be hit severely by climate change, especially in the Mekong Delta, which provides about 50% of the country's output. This region will be extremely vulnerable and affected by natural disasters, especially salinity intrusion (Vu et al., 2018). In fact, the Mekong Delta has been identified as one of the regions in the world being most vulnerable to climate change (Nguyen et al., 2019) and most studies claimed that salinity intrusion is one of major problems in the Mekong Delta, which tends to be exacerbated in the future due to sea level rise and declining upstream discharge (Tran Quoc Dat et al., 2012; Tran Hong Thai et al., 2014). This can lead to the region's rice production development. In the past, there were many research on sustainable livelihoods, vulnerability assessment in the Mekong Delta (Ministry of Science and Technology, 2016; Nguyen Thanh Binh, 2012; Tran Hong Thai et al. et al, 2014; ADB, 2011; Dinh et al, 2012; Birkmann et al, 2012; Miller, 2014; Trung and Thanh, 2013; Can et al, 2013; Phung et al, 2016 ...). However, these studies mainly focused on climate change (temperature change, rainfall) and did not specify which form of livelihood is vulnerable in the context of salinity intrusion. Furthermore, authors of these studies did not quantify the impact of salinity intrusion on households' livelihood or research factors which could minimize the negative effects of salinity intrusion. Quantifying these effects will provide important insights in the amount of money should be spent on mitigation, and also orientate where, when and how the adaptation policy should be implemented (Mendelsohn, 2008). Therefore, it is essential for further studies to study which form of livelihood is vulnerable in the context of salinity intrusion as well as factors that reduce influence of salinity intrusion in the Mekong Delta in order to provide appropriate policies. Taken into account these practical requirements and research shortcomings, the author selected "Vulnerability and livelihood outcomes in the context of salinity intrusion in the Mekong Delta" as the topic of the dissertation. 2. Research objectives and questions Research objectives General Objective: The research was conducted to evaluate livelihood vulnerability in the context of salinity intrusion in the Mekong Delta to indicate which areas and subjects are more vulnerable. Concurrently, the study also aimed at assessing the impacts of LVI components (exposure, sensitivity, adaptive capacity) on livelihood outcomes, and taking into account the regulatory role of adaptive capacity in mitigating the effects of salinity intrusion on livelihood outcomes in the Mekong Delta. Specific objectives - To complete the theoretical model in evaluating impacts of LVI components on livelihood outcomes in the context of salinity intrusion in the Mekong Delta. - To measure livelihood vulnerability in the context of salinity intrusion in the Mekong Delta according to each local area and households' characteristics based on the analysis of exposure, sensitivity and adaptive capacity. - To evaluate the influence of LVI components on livelihood outcomes in the 3 context of salinity intrusion in the Mekong Delta as well as assess the regulatory role of adaptive capacity in mitigating the effects of salinity intrusion on livelihood outcomes in the Mekong Delta. 4 CHAPTER 1 OVERVIEW 1.1 Research overview of livelihood Research questions - Livelihood vulnerability in the context of salinity intrusion in the Mekong Delta happens to which group of subjects and their degree of vulnerability? livelihood: (1) United Nations Development Program (UNDP), (2) A humanitarian agency delivering emergency relief and international development- Cooperative for American - How do LVI components (exposure, sensitivity, adaptive capacity) affect livelihood outcomes in the Mekong Delta? Remittances to Europe-CARE and (3) Department for International Development (DFID). All three organizations use sustainable livelihood as a strategic approach for poverty - How does adaptive capacity affect the mitigation of effects of salinity intrusion on reduction, and they also use similar definitions of sustainable livelihood. Nevertheless, UNDP and CARE use sustainable livelihood and the sustainable livelihood framework to livelihood outcomes in the Mekong Delta? 3. Research subjects and scope Research subjects The dissertation studied components of livelihood vulnerability (exposure, sensitivity and adaptive capacity), livelihood outcomes and the effects of these components on livelihood outcomes of households in the context of salinity intrusion. Research scope - In terms of spatial aspect: According to Appendix 06 in “Decision No. 90/QD-TTg The author conducted an overview of three approaches related to sustainable plan and build programs and projects, while DFID utilizes sustainable livelihoodss as a primary framework for the analysis. In addition, CARE supports livelihood security at the community level, while UNDP and DFID not only concentrate on the community level, but also emphasize on addressing environmental policies, macroeconomic reform and legislation for effective poverty reduction. Therefore, after the research review, the author affirmed that DFID's approach to sustainable livelihood is suitable with the research objectives of the dissertation. dated January 12, 2016 of the Prime Minister on approving the planning of national natural resource and environmental monitoring network in the period of 2016-2025 with a vision towards 2030 ”, as of early 2016, the whole Mekong Delta region had 35 saline measuring stations located in eight provinces, including Long An, Tien Giang, Ben Tre, Tra Vinh, In general, vulnerability in climate change is affirmed by numerous studies which results in the diversity in definitions. Three general perspectives on vulnerability can be Kien Giang, Soc Trang, Bac Lieu, and Ca Mau. Therefore, the thesis will focus on researching households affected by salinity intrusion in the above eight provinces with the listed as the physiological, social and integrative perspectives respectively. Specifically, the integrative perspective is considered as a modern model in analyzing the vulnerability in assumption that all households living in the same area are equally affected by salinity intrusion. climate change. It provides a broad conceptual and analytical foundation by allowing the integration and application of different conceptual contexts as well as a range of potentially - In terms of temporal aspect: The study concentrated on analyzing LVI components and assessing the impacts of these components on livelihood outcomes in the context of complementary methods and tools. salinity intrusion in the Mekong Delta in the period of 2014-2018. 1.2 Research overview of vulnerability in the context of climate change 1.2.1 The approach to vulnerability 1.2.2 Main components of vulnerability As previously stated, the integrative perspective is considered as a modern model in analyzing the vulnerability in climate change. Thus, it was preferred and used by many authors through its three components (exposure, sensitivity and adaptive capacity) (Hahn et al. et al, 2009; Shah et al., 2013; Zhang et al., 2019...). 1.2.3 Methods for vulnerability evaluation Among methods for vulnerability assessment, the index method is considered optimal and is widely used in various studies. The act of prioritizing the use of indicators to describe and quantify problems is explained for three main reasons. First, it provides a reference point in evaluating frameworks for development policy (Kelly and Adger, 2000, Eriksen and Kelly, 2007). Secondly, it can offer information for the development of adaptation and 5 mitigation plans (Gbetibouo et al., 2010). Thirdly, it provides a standardized means of measuring vulnerability, which allows a comparison of different contexts. This will lead to a 6 During the overview, the author discovered that there were not many studies on the direct effects of vulnerability on livelihood outcomes. Most research often focused on the possible solution in establishing priorities in resource allocation for adaptation and mitigation (Preston et al., 2011; Heltberg and Siegel, 2009). Therefore, within the scope of impacts of one of LVI components on livelihood outcomes. Firstly, regarding the impacts of exposure on livelihoods outcomes, many studies this thesis, the attendant also used the index method to measure ivelihood vulnerability. 1.2.4 Analysis framework of vulnerability were conducted to analyze the influence of climate change on households' livelihood outcomes. The exposure often reduces income, expenditure and is the cause of consistent According to Nguyen Thi Vinh Ha (2016), there were seven frameworks in the world currently used to analyze and assess vulnerability caused by natural disasters including (1) poverty and poverty traps. However, there is a lack of practical evidence when considering the effects of salinity intrusion on livelihood outcomes in the Mekong Delta, where is Double structure model, ( 2) harzard model, (3) Pressure and Release model, (4) UNISDR's harzard reduction model, (5) Sustainable livelihood framework, (6 ) BBC model and (7) vulnerability analysis model by Tuner et al. (2003). Based on each author or organization's identified as one of the most vulnerable regions in the world to climate change, especially salinity intrusion (Nguyen et al., 2019; Vu et al., 2018; Tran Quoc Dat et al, 2012; Tran viewpoint, vulnerability can depend on the probability of occurrence of a specific hazard, and/or the degree of exposure or adaptive capacity , prevention, response and recovery of the environmental system. Therefore, depending on different assessment objectives, different evaluation models will be used. According to Nguyen Thi Vinh Ha (2016), in the context of Vietnam, the database for research is often limited and not easy to collect, the double structure model by Bohle (2001), vulnerability analysis model by Turner et al. (2003), the BCC model (2006) and the DFID's sustainable livelihood framework (2001) can Hong Thai et al, 2014). Secondly, in terms of influence of sensitivity on livelihood outcomes, there is a lack of detailed research of this issue. Most of previous studies only concentrated on aspects of sensitivity such as health, food or water sources. And most results showed that, when families are sensitive to these aspects, it reduces crop productivity, household income, and spending. be applied to evaliate the vulnerability due to natural disasters in Vietnam. However, DFID's sustainable livelihood framework (2001) is particularly appropriate Thirdly, regarding the effects of adaptive capacity on livelihood outcomes, they were proven by many scholars. Scholars often analyzed adaptive capacity in terms of capital resources (natural, human, social, financial, and physical resources ) and they found that all these resources play a positive role in improving livelihood outcomes of households. with vulnerability in climate change as it provides an analytical framework for all the key components of livelihood and related contextual factors affecting livelihood. All are closely Fourthly, in terms of the regulatory role of adaptive capacity, although previous studies confirmed the important role of adaptive capacity in reducing negative impacts of related to factors that make households or communities more sensitive and impact their ability to cope with environmental changes (Eakin and Luers, 2006). LVI component, they mainly approached from a macro perspective and did not thoroughly consider its regulatory role, only analyzed small components in adaptive capacity in the 1.3 Overview of index method to measure livelihood vulnerability in the context of climate change context of vulnerability in general and salinity intrusion in particular. Therefore, it is essential to carry out studies on the regulatory role of adaptive capacity in the relationship of After reviewing domestic and foreign studies, it can be confirmed that the index method is considered to be optimal and is widely used to measure livelihood vulnerability in salinity intrusion and livelihood outcomes. the context of climate change. This method was developed by Hahn et al. (2009) and applied or modified by many studies (Sarker et al., 2019; Zhang et al., 2019; Peng et al., 1.5 Research gaps Therefore, there are still some notable research gaps in analyzing the vulnerability 2019; Tjoe, 2016; Adu et al, 2018; Huong et al, 2019). However, most of the studies applying LVI used the weighted balance which was criticized because the same weights are and livelihood outcomes, specifically: (1) Most studies applying LVI used weighted balance, but this method was criticized as same weights are applied to different components of LVI. Therefore, it is necessary to develop applied to different components of LVI (Beccari, 2016; Miller; et al, 2013; Abeje et al., 2019). Therefore, it is necessary to develop a more suitable vulnerability calculation method a more suitable vulnerability calculation method to produce more convincing results. (2) Regarding livelihood vulnerability, domestic and international research often to produce more convincing results. focused on climate change scenarios (temperature change, precipitation)to calculate LVI to indicate which regions and who are affected but without thoroughly studied the context of 1.4 Overview of impacts of LVI components on livelihood outcomes in the context of salinity intrusion salinity intrusion in the Mekong Delta - where is confirmed as one of those regions in the 7 world being the most vulnerable to climate change, especially salinity intrusion. (3) Most studied only measured LVI without analyzing the overall role of LVI components in livelihood outcomes. (4) Previous studies only explored the regulatory role of several small components in adaptive capacity, and did not analyze specifically the regulatory role of adaptive capacity in the context of salinity intrusion. Therefore, the main objective of the dissertation is to assess livelihood vulnerability in the context of salinity intrusion in the Mekong Delta with the application of unequal weight proposed by Iyengar and Sudarshan (1982), to concurrently evaluate the impacts of LVI components (exposure, sensitivity, adaptive capacity) on livelihood outcomes, to specifically indicate the regulatory role of adaptive capacity in reducing influence of salinity intrusion on livelihood outcomes in the Mekong Delta. With the above objectives, the author hopes to resolve all research gaps and offer some recommendations to minimize livelihood vulnerability in the context of salinity intrusion in the Mekong Delta. 8 CHAPTER 2 LITERATURE REVIEW 2.1 Livelihood and sustainable livelihood framework 2.1.1 Livelihood and sustainable livelihood The definition of livelihood that is frequently used and cited in later studies is based on the concept of livelihood by Chambers and Conway (1992), in which livelihood is, in the simplest sense, the means to make a living. In a more detailed description, Chambers and Conway defined that livelihood includes the capabilities, resources, and activities required to provide the daily life. Similarly, Scoones (1998) stated that livelihood includes necessary abilities, resources (including physical and social resources) and activities as a means of life for human beings. Taken into account the above definitions, DFID (2001) also argued that livelihood includes the capabilities, resources and activities necessary to serve as a means of life for human beings. In summary, livelihood is the use of resources necessary to carry out activities to achieve desired results (Vu Thi Hoai Thu, 2013). 2.1.2 Sustainable Livelihood Framework of DFID (2001) Sustainable livelihood framework of Department for International Development DFID (2001) is a tool designed to analyze various factors that influence livelihood outcomes, especially those creating opportunities or posing challenges for livelihood(Twigg, 2001). Accordingly, all households have a means of making a living (livelihood) based on available livelihood resources (five types of resources) in the context of certain policies and institution in the local areas. These factors are also influenced by external factors such as storms, floods, droughts, salinity intrusion... and seasonal elements. The household's selection of livelihood based on current livelihood resources is the result of the interaction between these groups of factors. Figure 2.1: Sustainable Livelihood Framework of DFID (2001) 9 The purpose of the sustainable livelihood framework is to support policymakers and researchers from many fields in participating in the discussion of factors influencing 10 potential to respond and reduce the vulnerability of a particular system. Adaptive capacity is highly dependent on the existence and access to resources such as natural resources, livelihood outcomes and their importance and interaction. This facilitates the identification of suitable elements for livelihood support based on a clear analysis of each factor. financial capacity, infrastructure, political institutions, human resources and social relationships (Brooks and Adger, 2004). Consequently, many scholars had confirmed that the sustainable livelihood framework of DFID (2001) is the most suitable method to analyze livelihood outcomes and disaster 2.2.3 Measurement of livelihood vulnerability due to salinity intrusion vulnerability (Twigg, 2001; Nguyen Duc Huu, 2016). This is also a theoretical framework that the author used to solve research questions in the dissertation. expression of individuals, households, communities, nations or ecosystems affected by an adverse environmental or socio-political factor characterized by the frequency, intensity, 2.2 Livelihood vulnerability in the context of salinity intrusion 2.2.1 Vulnerability The research overview has provided three broad viewpoints on vulnerability: time and space of the event (Turner et al., 2003; Adger, 2006;). Therefore, in the context of salinity intrusion and research of the household unit, the degree of exposure is the presentation of a household affected by salinity intrusion characterized by the frequency, biophysical, social, and integrated perspectives. It also confirms that the integrated viewpoint of vulnerability as a modern model in analyzing vulnerability in the context of intensity, time and sapce of salinity intrusion. Based on the research overview and data of salinity intrusion in the Mekong Delta, the author selected three indicators to measure the climate change. Therefore, in this dissertation, vulnerability is approached from an integrated point of view, specifically the definition of vulnerability by Intergovernmental exposure of salinity intrusion, namely: (1) annual average salinity; (2) Salinity being above 4 ‰; (3) Salinity fluctuation in the month with most serious drought (April). Panel on Climate Change (IPCC, 2001) was frequently cited (Ha Hai Duong, 2014; Abeje et al., 2019; Parry, 2007). Accordingly, vulnerability is the degree to which a natural or social system can be vulnerable or unable to cope with adverse effects due to extreme weather patterns and climate change). The IPCC clearly identified vulnerability as a function of Measurement of sensitivity: To measure the sensitivity, most authors used mainly three sub-factors including (1) health; (2) food sources and (3) water sources. Each sub-factor includes one of the component indicators. This dissertation also three factors including exposure, sensitivity, and adaptive capacity. 2.2.2 Livelihood vulnerability As stated above, livelihood is considered sustainable if it can cope with and recover Measurement of the exposure of salinity intrusion: As stated above, exposure is an measured the sensitivity based on the above three components and components of the sensitivity were measured through the main water source for domestic use; untreated water for domestic use; crop diversification index; livestock diversification index; the monthly rate indicating the lack of two meals a day, the rate of injured or sick family from harzards, maintain or enhance its abilities and assets, while not weakening its natural resources. Therefore, Scoones (1998) proposed that if livelihoods are unable to engage in dealing (temporary adjustments) or adapting (long-term change), it is considered vulnerable. Vulnerability is therefore used as an attribute of livelihoods and thus it emphasizes people members in need of caretaking, number of days for sick leave per person. Measurement of adaptive capacity: Adaptive capacity is measured through five and how they manage their lives (Murungweni et al., 2011). Hence, in the context of salinity intrusion, livelihood vulnerability refers to the degree 2017; Zhang et al., 2019). Based on the research overview and on the availability of data on households' living standard in 2014, 2016, 2018, this dissertation measured natural capital via agricultural and forestry area per capita; land diversification; rice cultivated area per to which communities/households can be vulnerable or unable to overcome the effects of salinity intrusion. It is also a function of three factors including exposure, sensitivity and livelihood assets (natural capital, human capital, physical capital, financial capital, social capital) and this method was also used by many authors (Pandey et al., 2015; Gerlitz et al., adaptive capacity, specifically: Exposure is the presentation of individuals, households, communities, nations or capita; cereal cultivated area per capita. Also, the author calculated human capital through the proportion of household members having jobs; Head of household with professional and technical qualifications; Head of household graduated from primary schools or higher ecosystems affected by an adverse environmental or socio-political factor characterized by the frequency, intensity, time and space of the event (Turner et al., 2003; Adger, 2006). education. In addition, the study measured physical capital via the durable goods diversity index; average net residual value; living area per capita; types of house. The author also Sensitivity is the degree to which a system is affected (either positively or negatively) by one or more factors from internal or external environment (IPCC, 2001). . calculated financial capital through access to savings; access to loans in cash and goods; livelihood diversity index and measured the social capital through the proportion of household Adaptive capacity (Turner et al., 2003) or reactive capacity (Gallopín, 2006) is the members joining the union; number of support forms; and number of means of media. 11 Most of the above-stated studies used equal weight and this method was criticized 12 Impacts of adaptive capacity on livelihood outcomes: As stated above, the dissertation used the framework of sustainable livelihoods by DFID (2001) due to the because the same weights were applied to different components of LVI (Beccari, 2016; Miller et al., 2013; Abeje et al., 2019). Therefore, the dissertation will apply unequal weight suitable classification of adaptive capacity according to types of capital. Accordingly, adaptive capacity is measured through five livelihood assets (natural capital, human capital, as proposed by Iyengar and Sudarshan (1982). Accordingly, LVI is calculated as follows: physical capital, financial capital, social capital). The results demonstrated that natural capital, human capital, physical capital, financial capital, social capital have positive Measurement of LVI LVI=E*We + S*Ws + A*Wa (iv) LVI ranges from 0 (least vulnerable) to 1 (most vulnerable). wE, wS, wA are weights of exposure, sensitivity and adaptive capacity respectively, in which wE + wS + wA = 1 are weights of exposure, sensitivity and adaptive capacity respectively, in which The calculation of LVI according to the formula (iv) will be explained in Chapter 3 Methodology. 2.3 Livelihood Outcomes Previous studies all indicated that livelihood outcomes represent the outcomes of livelihood strategy through the use of resources. This is also the author's approach in carrying out the research. Accordingly, livelihood outcomes are achievements or outputs of livelihood strategies, such as increasing income, increasing welfare, minimizing vulnerability, improving food security and using sustainable natural resources. Scholars often used different indicators to measure economic performance, but income is widely impacts on households' livelihood outcomes. When farmers can increase these capital sources while applying them effectively in economic activities, it will increase their livelihood outcomes and vice versa, when the household does not invest in capital, their livelihood outcomes will not be as good as expected. Therefore, the dissertation proposed the research hypothesis: H3 (a1-a17): 17 component indices of adaptive capacity (agricultural and forestry area per capita; land diversification; rice cultivated area per capita; cereal cultivated area per capita, the proportion of household members having jobs; head of household without professional and technical qualifications; head of household not graduated from primary schools or higher education, durable goods diversity index; average net residual value; living area per capita; types of house, access to savings; access to loans in cash and goods; livelihood diversity index and the proportion of household members not joining the union; number of support forms; and number of means of media) have a positive correlation with livelihood outcomes of households in the Mekong Delta. recognized as the most important factor in sustainable livelihood outcomes (Ojong, 2011; Albert et al., 2007). Therefore, this dissertation also used income index to measure 2.5 The regulatory role of adaptive capacity in minimizing impacts of salinity intrusion on households' livelihood outcomes livelihood outcomes. Similar to the analysis of the influence of adaptive capacity on households' livelihood outcomes, when studying the regulatory role of adaptive capacity in minimizing impacts of 2.4 Impacts of LVI components on livelihood outcomes Impacts of exposure on livelihood outcomes: Studies showed that salinity intrusion is considered to be a serious issue that not only reduces agricultural potential, but also produces adverse effects on livelihood outcomes (Haider and Hossain, 2013). Therefore, the thesis proposed the research hypothesis: H1: The exposure of salinity intrusion negatively impacts livelihood outcomes of households in the Mekong Delta. Impacts of sensitivity on livelihood outcomes: As stated above, sensitivity is measured through three sub-components: health, water and food. Studies showed that when households have health problems, and they do not have access to hygienic water and food, it adversely affects their livelihood outcomes. Therefore, the thesis proposes the research hypothesis: H2 (a1-a7): seven indices of sensitivity (the main water source for domestic use; untreated water for domestic use; crop diversification index; livestock diversification index; the monthly rate indicating the lack of two meals a day, the rate of injured or sick family members in need of caretaking, number of days for sick leave per person) have a negative correlation on livelihood outcomes of households in the Mekong Delta. salinity intrusion on households' livelihood outcomes, the author also concentrated on analyzing the regulatory role of five sources of capital respectively. Studies illustrated that households can reduce damage from natural disasters by increasing the resistance of assets exposed to impacts of disasters. This implies that in order to mitigate the negative influence of disasters, households can focus on enhancing their livelihood assets. Therefore, the dissertation proposed the research hypothesis: H4 (a1-a17): 17 component indices of adaptive capacity (agricultural and forestry area per capita; land diversification; rice cultivated area per capita; cereal cultivated area per capita, the proportion of household members having jobs; head of household without professional and technical qualifications; head of household not graduated from primary schools or higher education, durable goods diversity index; average net residual value; living area per capita; types of house, access to savings; access to loans in cash and goods; livelihood diversity index and the proportion of household members not joining the union; number of support forms; and number of means 13 of media) have the role of regulating to reduce impacts of salinity intrusion on the livelihood outcomes of households in the Mekong Delta. 2.6 Research model and hypotheses Based on the relationships in the theoretical basis and research overview, the author proposed the following model: 14 H4 (a1-a17): 17 component indices of adaptive capacity (agricultural and forestry area per capita; land diversification; rice cultivated area per capita; cereal cultivated area per capita, the proportion of household members having jobs; head of household without professional and technical qualifications; head of household not graduating from primary schools or higher education, durable goods diversity index; average net residual value; living area per capita; types of house, access to savings; access to loans in cash and goods; livelihood diversity index and the proportion of household members not joining the union; number of support forms; and number of means of media) have the role of regulating to reduce impacts of salinity intrusion on the livelihood outcomes of households in the Mekong Delta. Figure 2.3: Research model Source: DFID (2001), research by Hahn et al. (2009). Research hypotheses H1: Exposure of salinity intrusion has a negative correlation with livelihood outcomes of households in the Mekong Delta. H2 (a1-a7): seven components of sensitivity (the main water source for domestic use; untreated water for domestic use; crop diversification index; livestock diversification index; the monthly rate indicating the lack of two meals a day, the rate of injured or sick family members in need of caretaking, number of days for sick leave per person) have a negative correlation with livelihood outcomes of households in the Mekong Delta. H3 (a1-a17):17 component indices of adaptive capacity (agricultural and forestry area per capita; land diversification; rice cultivated area per capita; cereal cultivated area per capita, the proportion of household members having jobs; head of household without professional and technical qualifications; head of household not graduating from primary schools or higher education, durable goods diversity index; average net residual value; living area per capita; types of house, access to savings; access to loans in cash and goods; livelihood diversity index and the proportion of household members not joining the union; number of support forms; and number of means of media) have a positive correlation with livelihood outcomes of households in the Mekong Delta. 15 16 CHAPTER 3 METHODOLOGY 3.1. Approaches In order to fulfill research objectives, the sustainable livelihood framework by DFID (2001) (Figure 2.1) approach was used to discover factors facilitating or hindering farmers from developing and implementing livelihood strategies to achieve expected livelihood outcomes. On the basis of the sustainable livelihood framework by DFID (2001) and the theoretical framework for assessing livelihood vulnerability developed by Hahn et al. (2009), indices including exposure (E), sensitivity (S) and adaptive capacity (A) are chosen according to the function: V = f (E, S, A). The determination of these components is based on a review of previous studies. 3.2. Data collection method The study mainly used two sets of data: (1) salinity measurement data of 32 stations provided by the Southern Hydrometeorology Station to calculate the exposure and (2) data set of households' living standards in 2014, 2016 and 2018 by the General Statistics Office of Vietnam to review households' characteristics as well as calculate the sensitivity and adaptive capacity of households. In addition, the study also used other data related to population, labor and employment, economic development, poverty, income, expenditure, climate change, salinity intrusion... of the country in general and the Mekong Delta in particular. The data was collected from previous research and organizations such as Ministry of Natural Resources and Environment, Southern Institute of Irrigation Science, Institute of Meteorology, Hydrology and Climate Change, General Statistics Office, Provincial Statistics Office... 3.3 Data processing method 3.3.1 Calculation method of livelihood vulnerability index The process of identifying and calculating the livelihood vulnerability index can be summarized as shown in Figure 3.2. Figure 3.2: The process of identifying and calculating livelihood vulnerability index 3.3.2 Estimation in Regression Model Estimation in regression model used in this study is econometric regression. The general research model is presented as follows. ln(Yijt) = βo + Ejtβ1 + Sijtβ2 + Aijtβ3 + AijtEjtβ4 + Gtβ5 +εijt (7) 17 18 In which: Yijt: household's average income i in commune j in year t; CHAPTER 4 FINDINGS Ejt: exposure in commune j in year t; Sijt: household's sensitivity components i in commune j in year t; 4.1 Overview of the research area Aijt: household's adaptive capacity components i in commune j in year t; Gt: dummy variable of the year; in which, eight provinces bordering the sea including Long An, Tien Giang, Ben Tre, Tra Vinh, Soc Trang, Bac Lieu, Ca Mau and Kien Giang. The region is characterized by fertile εijt: unobserved variables. The author used the Hausman testing and it showed that the use of FEM model is more alluvium with a humid monsoon tropical climate. The irrigation resources of the Mekong Delta are complicated by the intertwined canal/river network as well as impacts of the appropriate. Concurrently, the author utilized the commune-level fixed-impact regression to remove commune-level variables that do not change over time and cannot be observed (such Mekong's flow and two tidal regimes: the tides of the East Sea and the semi-diurnal tide of the Gulf of Thailand. Therefore, during the dry season, when the upstream discharge as variables related to policies, infrastructure... in local areas). decreases, the tides strongly affect the upstream and inland canals, which results in severe salinity intrusion both in the river and in the land. Salinity intrusion remarkably affects the The Mekong Delta is located in the south of Vietnam, and it consists of 13 provinces, life, economy, society and livelihood of people in the Mekong Delta. 4.2 Measurement results of livelihood vulnerability in the Mekong Delta due to salinity intrusion The author evaluated the livelihood vulnerability in the Mekong Delta due to salinity intrusion through LVI index with five levels: from 0 - <= 0.20 being a very low vulnerability; > 0.2 - <= 0.4 being low vulnerability,> 0.4 - <= 0.6 being medium vulnerability, from> 0.6 - <= 0.8 being high vulnerability, from> 0.8 - <= 1 is being very high vulnerability. In the research period, in 2014 and 2016, the LVI index reached 0.472 points (in the range of 0.4 - 0.6) within the threshold of average livelihood vulnerability, in 2018 this index reached the level of low vulnerability due to LVI = 0.390 (range 0.2 to 0.4). During the period of 2014-2018, vulnerability was higher in coastal provinces, especially Ben Tre, Kien Giang, Bac Lieu, and Ca Mau had the highest LVI value (ranging from 0.445-0.612). The results showed that there is a difference in vulnerability in the coastal area with the upstream and middle regions with a significance level of 10%, but the same degree of significance did not prove the difference in the LVI between the middle and upstream subregions. The results also demonstrated that the poorer households are, the higher their vulnerability iss, as these groups often face a high level of exposure while their adaptive capacity is low. In terms of households' main source of income, the results showed that households with the main source of income from fisheries are most vulnerable. It also illustrated that there is a clear difference in vulnerability between a household owner with technical qualifications and a household owner with no technical qualifications. A household owner without technical expertise are about 1.36 times more vulnerable than those with technical qualifications. Similarly, the female owner of the household has a 19 higher degree of vulnerability than the male owner, however this gap is smaller than that of technical qualifications. The vulnerability of household owners being Kinh-ethnic is lower than that of other ethnic groups, but differences were not found according to the ethnicity of the household head. The study also analyzed the components constituting the vulnerability of the Mekong Delta's livelihood in the context of salinity intrusion. The results showed that the Mekong Delta not only had a high degree of exposure but also a 20 CHAPTER 5 DISCUSSION AND RECOMMENDATIONS 5.1 Discussion of research findings Based on the framework of sustainable livelihoods by DFID (2001) and the severe shortage of water resources. In 2018, water shortage was 19 times higher than (0.38 / 0.02) health problems, 3.2 times higher (0.38 / 0.16) than food problems. In terms theoretical framework for assessing livelihood vulnerability by Hahn et al. (2009), the of livelihood capital, it is illustrated that the Mekong Delta has a serious shortage of human capital, which is not only the smallest among five capital sources but also livelihood vulnerability according to the function: LVI = f (E, S, A). Concurrently, the gradually decreased in the period of 2014-2018. In addtion, the Mekong Delta also lacks financial capital and social capital. outcomes in the context of salinity intrusion in the Mekong Delta. Additionally, the research 4. Results of testing of research hypotheses 4.3.1 Impacts of vulnerability on livelihood outcomes livelihood outcomes in the Mekong Delta. Therefore, the obtained results obtained had The analysis of effects of LVI components (exposure, sensitivity, adaptive capacity) on households' livelihood outcomes in the Mekong Delta demonstrated that: Firstly, exposure of salinity intrusion negatively affects livelihood outcomes of households in the Mekong Delta. Specifically, with the significance of 5%, when salinity intrusion increased to 0.1 units, the income per capita in the household decreased dissertation assessed the exposure (E), the sensitivity (S) and adaptive capacity (A) of the thesis built a theoretical model to evaluate impacts of LVI components on livelihood studied the regulatory role of adaptive capacity in mitigating effects of salinity intrusion on answered all the research questions. Therefore, the results obtained have answered research questions. Specifically: The research has answered the first question: Livelihood vulnerability in the context of salinity intrusion in the Mekong Delta happens to which group of subjects and their degree of vulnerability? Research results show that, in the period 2014-2018, vulnerability is higher in coastal provinces, poor households with main income sources from fisheries, correspondingly about 0.058%. Therefore, hypothesis H1 is approved. Secondly, the study found that the index of crop and livestock diversification in the household heads with no technical expertise, The head of household is female and the head sensitivity components affected livelihood outcomes at a significant level of 10%. Therefore, H2 (a3) and H2 (a4) were accepted. context and agrees with most vulnerability studies. Thirdly, factors of adaptive capacity strongly affected livelihood outcomes. Specifically, hypotheses H3 (a1, a3, a4, a5, a6, a7, a8, a9, a11, a12, a14, a16, a17) were sensitivity, adaptive capacity) affect livelihood outcomes in the Mekong Delta? Specifically: approved and only four hypotheses in H3 including H3 (a2, a10, a13, a15) were not proved. Mekong Delta. This result is also consistent with studies on the effects of natural disasters 4.3.2 The regulatory role of adaptive capacity on livelihoods or household welfare such as Arouri et al (2015), Bui et al. (2014), Kirsch et of household is the Khome ethnic group. This finding is consistent with the Mekong Delta The research has answered the first question: How do LVI components (exposure, (1) exposure of saline intrusion negatively affects household livelihood outcomes in the The analysis of the regulating role of adaptive capacity proved that only three al. ( 2012), Baez and Santos (2008). (2) consider the degree of sensitivity to health, water components of adaptive capacity (the proportion of household members having jobs; types of house; number of means of media) play the regulatory role in the relationship of salinity sources, and food sources affecting household livelihood outcomes. It is found that only the intrusion and average income of households. Therefore, hypothesis H4 (a5, a11, a17) was approved. livestock + 1) has a positive impact on household livelihood outcomes. These results index of crop diversification (1 / (number of crops + 1) and livestock (1 / (number of disagree with previous studies, in particular: Makate et al (2016), Pellegrini and Tasciotti (2014), Kasem and Thapa (2011). (3) The factors of adaptive capacity have strong impact on livelihood results, such as: area of agricultural and forestry land, rice cultivation area per capita; Rate of employed household members, head of household with technical expertise, head of household with primary education or more; Number of durable goods, average