The environmental degradation whether local or at regional level poses threats to ecosystem services, human well-being, development and ultimately to national security if water, energy and climate change nexus is taken into account. Hence, energy, climate change and water build an intrinsic link between environmental security and national security. Currently, this complex relationship of environmental security with human and national security is reshaping the contemporary political discourse. As emerging environmental challenges such as climate change, water security and energy security are not only threatening development, but also national security by risking the environmental security. This study engrossed on the interaction of climate change, energy and water security with environment to assess the relationship of environmental security with development in the context of Pakistan and South Asia. The policies are strengthened if quantifiable parameters like inclusive representation, stakeholders’ engagement, transparency and environmental protection are included beside economic parameters. This study aimed to assess the potential of environment as a channel for diplomacy in South Asia-a region most vulnerable to climate change. The specific objectives were quantifying energy, water and climate change policies of countries in South Asia using simple multi-attribute rate technique (SMART) and multi-criteria decision analysis (MCDA) on technical, political and sustainability framework. Energy being essential for development is also a scarce commodity in many developing countries. Access to affordable and efficient energy is a basic human right and an imperative for human development as envisioned in 2030 agenda for sustainable development. Energy policies have to ponder technical, economic, environmental, social and political aspects for successful procurement of energy and endowment of energy resources in a sustainable manner. A robust energy policy covering multi-dimensions can assure access to affordable and sustainable energy and clean environment. The results indicated that energy policies in Pakistan have dominancy of economic criteria, fairly considered the social and technical criteria but least excogitated the environmental criteria. The dearth of environmental aspects not only results in environmental insecurity but also lag the development and provisions of the Sustainable Development Goals (SDGs). This study also presented the analysis of energy policies in South Asian region in development, energy trade and environmental security nexus. As energy trade esteems to reduce the cost and greenhouse gases emissions. The energy trade can foster economic development, functional area of the cooperation, sustainable energy supply and environmental security. The results not only comprehend feeble coherence among energy policies of individual countries in the region but also with the requirements of trade and regional environmental sustainability. Water insecurity has anticipated an ample threat to livelihood, economy, development, environment, peace, security and poverty reduction efforts in South Asia. Thirty-two technical, economic, social, environmental and political criteria were used to establish the relationship of water security with environmental security and development in national (Pakistan) and regional (South Asia). MCDA was also applied on regional water accords and treaties to assess the nexus of water and environmental security with conflict as well as considered international water laws. The results expressed various gaps in selected criteria which were probable cause of environmental damage, conflicts and mistrust. The divesting impacts of climate change have jeopardized the sovereignty, socioeconomic, political, national and environmental security across the world. The South Asia, a habitat of most vulnerable people to climate change has already agonized the damage due to climate and musing the risk to sustainable future. This study was conducted with objectives to portrait climate change scenario in South Asia, the analysis of climate change policies and plans in the South Asia and demonstrate the relationship of climate change with environmental security. The results revealed gaps in around twenty criteria particularly low institutional capacity, less coherence with Paris Agreement, the Sustainable Development Goals of 2015, and limited implementation of proposed mitigation and adaptation measures. Overall, the situation is critical for environmental security, economic development and poverty reduction. Meanwhile the regional disputes and lack of cooperation have imperilled environmental security and development. The region is looking for negotiation and diplomacy for dispute settlement, energy trade, and cooperation on shared water resources for sustainable development and to combat impacts of climate change in the region. This study has suggested quest for environmental diplomacy in South Asia to persuade cooperation for achieving the 2030 agenda for sustainable development goals, national and regional environmental security.