Climate action for a changing delta: Lessons from the Sundarbans

This World Environment Day, the United Nations Environment Programme has chosen Climate Action as its theme — and the timing could not be more urgent. In 2024, for the first time in recorded history, global average temperatures breached the 1.5°C ceiling that world leaders enshrined in the Paris Agreement less than a decade ago. The planet is no longer sending a warning. It is sending a verdict.

Yet distraction and denial persist. Heatwaves, fierce storms, melting glaciers, and rising seas are no longer distant phenomena — for tens of millions of people, they are the texture of daily life. The question is no longer whether we act, but how: through mitigation, by cutting the emissions that drive warming, and through adaptation, by reshaping how we live in a world that is already changing. Globally, progress on mitigation is visible: between 2019 and 2024, renewable electricity capacity surged to 2,326 GW. The Green Climate Fund has committed USD 7.73 billion — 59% of its total funding — to adaptation projects worldwide. Yet in India, only two of the 16 GCF-funded projects, worth USD 1.1 billion in total, address adaptation. For a country on the front lines of climate impacts, that imbalance is striking.

Nowhere is the human cost of this imbalance more tangible than in the Sundarbans, the vast mangrove delta straddling India and Bangladesh. Here, sea-level rise and intensifying storms are swallowing land — displacing not just people but also livelihoods. Farmers with no land become fishermen. Terrestrial wildlife retreats into shrinking forest fragments, largely uncounted, barring the tiger, and poorly documented. The delta is, in microcosm, what climate change looks like when it arrives not as a headline but as a flood at the door.

Storms destroy crops, kill livestock, and salinise fishponds. Floodwaters contaminate drinking sources, and vector-borne disease incidence can double in their wake. Homes built without concrete crumble or wash away. Government efforts in housing and piped water supply have brought real improvements, but when power lines go down — as they frequently do after major cyclones — water pumps stop, communications fail, and communities are cut off.

Communities across the Sundarbans are not passive. They diversify livelihoods, migrate seasonally for work, and with support from civil society organisations, experiment with salt-tolerant crops, community solar installations, and microinsurance schemes. Over time, these strategies can restore a household to where it stood before a disaster struck. This is resilience — the capacity to absorb a shock and return to the prior state.

But resilience, important as it is, is not the ceiling of ambition — it is the floor. For communities already living at the margins, returning to a precarious baseline is not a victory. What they need is adaptation: a fundamentally different process and goal. Adaptation does not merely restore — it transforms. It is the incremental, deliberate improvement of wellbeing even as climate pressures mount. Resilience asks: Can we survive this? Adaptation asks: can we thrive despite it?

Achieving adaptation requires collaboration across levels — communities, civil society, and governments working in concert. In the Sundarbans, promising innovations are emerging. Floating fish farms anchored in estuaries have proven remarkably storm-resilient, offering a model for aquaculture producers. Yet the delta’s many crab hunters and subsistence fishers — gatherers rather than producers — remain largely outside such solutions. Meeting their needs demands equal ingenuity.

Perhaps the most consequential battleground is the land itself. Conventional hard-engineering approaches to coastal erosion are losing the race against accelerating environmental change. Nature-based solutions (NbS) — restoring mangroves, deploying tidal mudflat systems, harnessing natural sediment dynamics — show real promise, offering both erosion control and biodiversity gains. But they are, by design, dynamic and iterative, demanding adaptive management, targeted monitoring, and a tolerance for uncertainty that sits uneasily within government frameworks built for a stable climate. Metrics designed for a world of “climate stationarity” — the assumption that past conditions predict future ones — are ill-suited to solutions that must evolve as the environment does.

Governance adds another layer of friction. Ecological systems do not respect administrative borders, yet responsibility for the Sundarbans is fragmented across multiple authorities at district, state, and national levels. Bringing nature-based solutions to scale demands not just scientific credibility — built painstakingly through proof-of-concept installations, peer-reviewed data, and sustained stakeholder engagement — but also the political will to align governance boundaries with ecological realities.

The world is moving in the right direction — but not fast enough. Paradoxically, the current moment of geopolitical turbulence may accelerate progress, less out of environmental conscience than economic self-interest, as nations increasingly recognise the costs of inaction. On this World Environment Day, that may be enough to give the transition the momentum it requires.

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