Rising seas, floods, droughts and extreme heat are already uprooting livelihoods across South Asia, the UN migration chief says, urging technology, funding and safe pathways to prevent a mass displacement crisis.

Climate change is rapidly eroding the foundations of life for millions across South Asia, threatening homes, farms and livestock and potentially forcing up to 40.5 million people to move by 2050 in a worst-case scenario, according to the United Nations. International Organisation for Migration (IOM) Director-General Amy Pope delivered the stark assessment during a visit to New Delhi on Friday, underscoring that displacement is increasingly becoming the first form of adaptation when communities can no longer feed themselves or their animals.

The warning comes as the region – home to nearly a quarter of the world’s population – faces a convergence of rising seas, intensifying floods, prolonged droughts and deadly heat. Pope pointed to a recent catastrophe in Nepal as a grim illustration of the risks. On 26 August, a mountain and glacier collapse in the Himalayas triggered flash floods that killed more than 1,300 people, left thousands missing and destroyed critical infrastructure. The IOM responded with humanitarian assistance, but the event highlighted how cascading cryosphere disasters can devastate communities far downstream.

Himalayan Disasters Signal Cascading Regional Risks

South Asia’s mountain systems, often called the “water towers of Asia,” are warming faster than the global average. Glacier retreat, permafrost thaw and extreme precipitation are producing sudden floods that travel through shared river basins, affecting India, Nepal, Bangladesh, Pakistan and beyond. Around 270 million people depend directly on these high-mountain water sources, while nearly two billion live downstream. Events like the August disaster in Nepal’s Bhotekoshi corridor demonstrate that national borders cannot contain the consequences.

Pope stressed that when agricultural production collapses and livestock cannot be sustained, movement becomes inevitable. “When they can’t produce food, when they can’t feed their livestock, it increases the likelihood of displacement,” she said. “The first adaptation is often for people to move.”

Extreme Heat and Urban Pressures Compound the Crisis

Beyond sudden disasters, slow-onset impacts are reshaping daily life. Extreme heat is already eroding the equivalent of 31 million full-time jobs a year across South Asia and could shrink the region’s economy by nearly 7 per cent by 2050, according to World Bank analysis. Cities are absorbing many of those forced to leave rural areas. In India, Pope noted, people are increasingly seeking refuge from unbearable heat in urban centres, accelerating unplanned urbanisation and placing pressure on already strained infrastructure and services.

Bangladesh and Pakistan face parallel pressures. Low-lying deltaic areas in Bangladesh remain highly vulnerable to sea-level rise, cyclones, salinity intrusion and river erosion. Projections suggest millions of internal climate migrants by mid-century. In Pakistan, intensified monsoons have repeatedly turned summer landscapes into flood zones, displacing large populations and damaging agriculture. Coastal cities such as Dhaka and Karachi are expected to receive significant numbers of climate migrants in coming decades, according to UN assessments.

Children and Vulnerable Groups Face Heightened Risks

The human cost is particularly acute for the young. A UNICEF report estimates that between 2016 and 2022, some 15.6 million children across South Asia were displaced by weather-related disasters – the equivalent of more than 6,100 children every day. Looking ahead, modelling suggests more than 35 million children could face displacement over the next three decades without urgent action. Disrupted education, healthcare and protection systems leave these children exposed to greater risks of exploitation, child labour and early marriage.

Women and informal workers also bear disproportionate burdens. Many depend on agriculture and outdoor labour, sectors highly sensitive to heat and rainfall extremes. When livelihoods vanish, families often resort to precarious migration routes that expose them to trafficking and exploitation.

Technology, Data and Funding as Tools for Prevention

Pope argued that technology and proactive government action can still limit the scale of forced movement. Better forecasting, early-warning systems and artificial intelligence can help identify high-risk areas before disasters strike. Investment in climate-resilient infrastructure, skills training and legal migration pathways can turn mobility into a planned adaptation strategy rather than a desperate flight.

She criticised the current shortfall in global adaptation finance and the lack of urgency among many governments. “There’s a lack of urgency globally about the risks that vulnerable communities are facing,” Pope said. Funding gaps leave communities without the resources needed to reinforce homes, diversify livelihoods or prepare for planned relocation when necessary.

Regional cooperation is equally critical. Shared river systems and interconnected climate risks mean that early-warning data, glacier monitoring and disaster response must cross borders. Initiatives such as the EU-backed climate mobility programme launched by Bangladesh and the IOM point toward practical steps: strengthening research, building institutional capacity and integrating mobility into national climate plans.

Safe Migration Pathways Offer a Path Forward

Pope emphasised that migration itself need not be a failure of adaptation. When supported by skills training, legal job opportunities and protections against exploitation, it can help families build resilience. Expanding regular pathways reduces the incentive for dangerous irregular journeys and allows remittances to support communities of origin.

South Asia’s climate challenges are not isolated. The region contributes relatively little to historical greenhouse-gas emissions yet faces some of the most severe impacts. The decisions taken by major emitters on mitigation and by the international community on adaptation finance will directly influence whether tens of millions of people are forced from their homes.

Time for Coordinated Global and Regional Action

The 40.5 million figure represents a worst-case trajectory. Stronger emissions reductions, scaled-up adaptation investment and coordinated regional planning can still reduce the numbers significantly. Governments in South Asia are beginning to incorporate climate mobility into policy frameworks, but implementation lags behind the accelerating pace of change.

For the international community, supporting South Asia’s efforts to build resilience is not only a humanitarian imperative but also a matter of global stability. Mass displacement carries risks of increased poverty, urban strain, social tension and irregular migration flows that extend far beyond the region’s borders.