Among the most urgent knock-on effects of climate stress is the growing wave of human migration, first internal, then potentially international.
NEW DELHI: South Asia is confronting a new class of security threats—those driven by climate change. In the BIMSTEC countries (Bangladesh, Bhutan, India, Myanmar, Nepal, Sri Lanka, and Thailand), rising seas, erratic weather patterns, and ecological degradation are no longer merely environmental concerns; they have become accelerators of instability. Major urban centres like Dhaka, Kolkata, Yangon, and Bangkok are among the most at-risk globally.
Among the most urgent knock-on effects of climate stress is the growing wave of human migration—first internal, then potentially international. As large swathes of land become uninhabitable due to salinization, floods, and drought, people are increasingly moving in search of stability, water, and opportunity. According to the World Bank, South Asia could see around 40 million internal climate migrants by 2050 in the absence of concerted action. These urban influxes can become flashpoints for tension, particularly in contexts already marked by inequality, ethnic divides, or resource scarcity. As climate shocks intensify, there’s also the possibility that migration will spill across national borders—particularly from Bangladesh into India’s northeastern states, where terrain is higher and perceived safety is greater. Assam has long been a site of agitation over alleged Bangladeshi immigration; climate migration could exacerbate these tensions, fuelling ‘insider vs. outsider’ narratives and ethnic polarization.
Large-scale displacement challenges governance itself. A flood of refugees or internally displaced persons (IDPs) can overwhelm local administrative systems, depress wages, strain social services, and destabilize host regions. If governments are unprepared or act punitively, displaced populations can become alienated and vulnerable to exploitation. Resource competition becomes fiercer—over land, water, and livelihoods—and the risk of conflict rises. Extremist groups may seize upon these grievances. The emerging concept of “eco-radicalism” is rooted in precisely this kind of disenfranchisement. The chain is clear: climate event leads to displacement, which triggers competition, then conflict, and potentially, violence. Unless states develop anticipatory mechanisms, climate migration could become one of the most destabilizing forces in the region.
Beyond disasters and displacement, there is a slower but equally damaging process unfolding: the steady erosion of the natural systems that sustain life in the BIMSTEC region. Agricultural productivity is already under pressure from rising temperatures and increasingly erratic rainfall. South Asia’s farming systems—particularly rice production in Bangladesh and India-are highly dependent on the monsoon, which is becoming more unpredictable. According to studies by the International Food Policy Research Institute, yields of staple crops like rice and wheat could decline by 15-20% in South Asia by mid-century under high-emissions scenarios. In a region where agriculture employs a large segment of the population and food inflation can have political consequences, these declines are not just economic—they are strategic.
Water, too, is becoming a scarce and politicized resource. South Asia’s major rivers—the Ganges, Brahmaputra, Meghna, Salween—flow across multiple borders. These rivers are fed by Himalayan glaciers, which are now retreating at an alarming rate. The result is a paradox: increased flood risk in the short term, followed by severe water scarcity in the long run. Disputes like the one between India and Bangladesh over the Teesta River, or between India and Nepal over the Mahakali, reflect how even modest reductions in flow can cause diplomatic tensions. As climate variability increases, countries may be tempted to secure their water needs unilaterally—through dams, diversions, or restrictions. But such actions can trigger a cycle of retaliation and distrust, undermining years of diplomatic progress. Water-sharing agreements that were designed for predictable monsoon flows may buckle under climate uncertainty. Without stronger, more adaptive institutions, the risk of water-based conflict will grow.
Despite the scale of the challenge, the tools for cooperative response exist—and BIMSTEC is well-placed to build them. The BIMSTEC Centre for Weather and Climate in India already supports regional early warning systems. This could be expanded into a full-fledged ecological observatory to monitor river basins, forest degradation, and population vulnerability in real time. Establishing a climate security task force under BIMSTEC’s environment pillar would enable cross-sector collaboration between meteorologists, defence planners, and humanitarian agencies. A regional ‘River Basin Restoration Fund’ could pool resources for watershed protection and reforestation. Equally, initiatives like joint mangrove restoration—particularly in the Sundarbans—can serve as both a climate buffer and a diplomatic bridge. These measures, while technical in appearance, have strategic value. They can mitigate disaster risk, strengthen trust among states, and reduce the triggers for migration and conflict.
BIMSTEC member states must embed environmental indicators into their national security calculus. Ministries of defence and home should treat climate impacts as destabilizing forces—not abstract futures, but real pressures reshaping population flows, economic vulnerabilities, and geopolitical priorities.
*Tarun Agarwal and Pooja Arora are PhD candidates at Jawaharlal Nehru University.