A devastating spell of extreme rainfall and landslides in Indonesia has pushed the critically endangered Tapanuli orangutan closer to extinction, with a new scientific study estimating that at least 58 individuals—around 7% of the species’ entire global population—were killed during a catastrophic weather event in North Sumatra last year. The findings have intensified concerns over the growing impact of climate change on vulnerable wildlife populations and fragile ecosystems.
The Tapanuli orangutan, regarded as the world’s rarest great ape, survives only in the Batang Toru forest ecosystem on the Indonesian island of Sumatra. Researchers found that torrential rainfall exceeding 1,000 millimetres within a few days triggered widespread flooding and landslides across the region, causing extensive destruction to the orangutans’ habitat and severely disrupting the already fragile population.
According to the study, approximately 8,300 hectares of primary forest habitat—representing nearly 12% of the area occupied by the species—were damaged or destroyed by landslides and flooding. Scientists warned that the losses could have long-term consequences for the survival of the species, whose total population is estimated to be fewer than 800 animals. Even relatively small annual declines can have a significant impact on their ability to recover and maintain a viable breeding population.
Researchers noted that climate change likely intensified the rainfall event, making such disasters more frequent and severe. The study highlighted how extreme weather, combined with habitat fragmentation, deforestation, mining activity and infrastructure development, is increasing the extinction risk faced by the species. Conservationists have long argued that environmental degradation in the Batang Toru landscape has weakened the ecosystem’s resilience to natural disasters.
The disaster also had a devastating human toll. Floods and landslides across the region killed more than a thousand people and damaged hundreds of thousands of homes, underscoring the broader social and environmental consequences of extreme weather events in Southeast Asia. Environmental groups have linked the severity of the destruction to rapid deforestation and unsustainable land-use practices that have reduced the forest’s ability to absorb heavy rainfall and stabilise slopes.
In response to mounting concerns, Indonesian authorities have initiated investigations into industrial activities operating within and around the Batang Toru ecosystem. The government has also temporarily suspended certain large-scale operations while assessing environmental risks and conservation measures. Scientists and conservation organisations are urging authorities to strengthen habitat protection, halt activities that degrade forest landscapes and develop a comprehensive recovery plan for the species.
Experts warned that without urgent intervention, the Tapanuli orangutan could become the first great ape species in modern history to go extinct. They stressed that protecting the remaining habitat, restoring damaged forests and addressing the underlying drivers of climate change are essential to securing the future of one of the planet’s most endangered primates.
