Assessing households’ adaptive capacity to salinity intrusion in the Vietnam Mekong Delta

Salinity intrusion (SI), intensified by climate change, poses escalating threats to agricultural livelihoods in Vietnam’s Mekong Delta. This study assesses the adaptive capacity of 318 farming households in Kien Giang Province across three distinct farming systems: double-rice, shrimp-rice, and shrimp-mono, each experiencing varying levels of salinity exposure. Using household surveys, focus groups, and stakeholder interviews, we employed Principal Component Analysis (PCA) to develop an Adaptive Capacity Index (ACI) within the Sustainable Livelihood Framework. The PCA explained 53.1% of total variance across 19 indicators encompassing human, social, financial, physical, and natural capital dimensions. Results reveal moderate adaptive capacity (ACI: 0.33–0.66) with significant variation across farming systems. Double-rice farmers demonstrate the highest ACI scores (0.41) due to necessity-driven adaptation and greater government support,, while shrimp-based systems shows lower capacity despite operating in theoretically suitable brackish conditions. . Key constraints include inadequate natural and financial capital, restricted credit access (particularly among ethnic Khmer communities), and limited technical knowledge. While government initiatives have facilitated adaptation, infrastructure gaps persist, with over 50% of households reporting continued SI damage. Policy implications emphasize differentiated approaches: targeted financial mechanisms, smart water management systems, culturally sensitive capacity-building programs, and participatory governance structures that address ethnic disparities in climate adaptation.