Climate crisis pushing eastern India’s world heritage parks to the brink

The International Union for Conservation of Nature’s (IUCN) latest 'World Heritage Outlook 2025' report has sounded an urgent alarm for three of eastern India’s most iconic natural heritage sites — the Kaziranga National Park and Manas National Park in Assam, and the Sundarbans National Park in West Bengal.

All three parks are Unesco World Heritage Sites, recognised for their natural importance.

Not poaching or habitat loss

The global conservation body, in a report released on October 11 at its World Conservation Congress in Abu Dhabi, pointed out that it is climate change, not poaching or habitat destruction, which has emerged as the most significant threat to the ecological integrity of these protected areas.

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While Kaziranga has been rated as “Good with Some Concerns,” the report places both Manas and the Sundarbans under the more alarming “Significant Concern” category.

“This marks a shift in global conservation assessments, where the slow-burning impacts of rising sea levels, erratic weather, and disease outbreaks are now overtaking more immediate and visible dangers such as illegal wildlife trade,” said Subhamoy Bhattacharjee, a conservationist photographer who had worked with the Wildlife Trust of India.

Brojo Kumar Basumatary, a conservationist working to promote sustainable livelihood around Manas Tiger Reserve in Assam, noted that the report confirms what many on the ground have been observing for years, that “climate-induced flooding and habitat stress are no longer hypothetical threats".

"They are here, and they are changing the very character of these ecosystems,“ said Basumatary.

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Unpredictable floods hurt Kaziranga

While Kaziranga has seen major success in curbing poaching of rhinoceros, which was a long-standing concern, the increasingly unpredictable flood cycles of the Brahmaputra are damaging grasslands and disrupting animal movement patterns, especially during monsoon months.

“Kaziranga remains a global model for rhino conservation, but rising flood intensity, tourism infrastructure, and habitat fragmentation demand stronger landscape‑level planning,” the report pointed out. It praised the park’s strong legal and institutional foundation and effective anti‑poaching mechanisms.

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The Manas National Park, which has spent the last two decades recovering from Bodo militancy and habitat degradation, finds itself in a precarious position once again, as indicated by the report’s findings.

Dams, grassland loss hit Manas

While climate-induced changes have emerged as the primary threat to the park’s biodiversity, other significant threats highlighted in the report include illegal encroachments, invasive species, infrastructure developments, such as hydropower dams in neighbouring Bhutan, grassland degradation, indiscriminate grass burning, and livestock grazing.

“Floods are getting more severe, and the dry spells are more prolonged. The park’s ecological balance, especially the grassland and wetland mosaics, is highly sensitive to these changes,” Basumatary said, explaining how the climate variability has brought new risks.

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Hydrological threats from upstream dams in Bhutan threaten the stability of the Beki Manas river system, potentially altering flood pulses, sediment flows, and aquatic habitats, according to Bhattacharjee.

The flooding in the park in turn facilitates the growth and spread of invasive plants like Mikania micrantha and Chromolaena, which have invaded over 150 sq km of its grasslands, degrading essential habitat, he added.

Sunderbans under threat

Perhaps the starkest warnings in the report are reserved for the Sundarbans, the world’s largest contiguous mangrove forest and a critical tiger habitat.

"Its status has been downgraded from 'Good with Some Concerns' in 2020 to 'Significant Concern' this time.

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The report noted that rising sea levels plus more frequent and intense storm surges undermine the health, stability, and diversity of mangrove forests.

“The danger is no longer abstract. The landscape is visibly fragmenting, the mangroves are dying, and communities are caught in a vicious cycle of ecological degradation and economic distress,” said Prasanjit Mandal of the Sundarbans Foundation, a non-profit organisation which works to preserve the region’s fragile ecosystem.

“Rising sea levels and increasing salinity are devastating traditional livelihoods, while storm surges and erosion have displaced thousands,” he added.

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Researchers have also noted an alarming decline in freshwater availability, which is essential for both mangrove health and the survival of species like the estuarine crocodile and the endangered fishing cat.

The report has warned that if these trends continue, the Sundarbans could face irreversible damage to its outstanding universal value.

Interlinked threats

The report also flagged several interlinked threats, including infrastructure development such as proposed power plants in the Bangladesh portion of the heritage area.

The Rampal super thermal power plant in Bangladesh is specifically mentioned as a “serious threat” due to its projected coal ash, wastewater discharge, shipping, and dredging activities.

Actions the report and experts recommend include: Restoring natural water flows (particularly for the Sundarbans), transboundary cooperation (for Manas), stricter regulation of infrastructure and tourism (for Kaziranga and Sundarbans), stronger disease monitoring and management, and incorporating climate adaptation into all future park planning.

Impact on human lives

What makes the crisis even more urgent is the direct impact on human lives.

In the Sundarbans, more than four million people live in villages interspersed among mangrove forests.

“As storm intensity and frequency rise, these communities are becoming increasingly vulnerable to displacement, water insecurity, and loss of agricultural land,” said Mandal.

Meanwhile, in Kaziranga and Manas, extreme weather events and shrinking buffer zones have heightened the human-wildlife conflict.