What the Sumatra Floods Reveal About Nature & Climate Risk
30 Mar 2026 - The Rimba Journal
“Those in refugee camps could only stare blankly, unsure of what tomorrow would bring,” recalls Syafrizaldi Jpang, Executive Director of the Orangutan Information Centre (OIC) in Aceh, North Sumatra.
Though the villages partnered with OIC and the Rimba Collective were relatively unscathed by the flooding, Syafrizaldi spent November and December 2025 travelling around Aceh delivering aid to displaced families in hard-hit areas beyond the project boundaries, while anxiously waiting to hear news from his own daughter in Banda Aceh.
On his travels, he saw first-hand the consequences of climate-related weather events on local communities. But in places where surrounding forests remained intact, the story was markedly different, demonstrating how proper land‑use decisions, combined with within‑value‑chain action can effectively reduce risk. In this article, we investigate the cause of the flooding, and examine the role forest protection played in mitigating its impacts.
Cause and Effect: What Happened in North Sumatra?
In late November and early December 2025, heavy rainfall swept across Aceh, North Sumatra and West Sumatra, triggering floods and landslides. More than 1,200 people lost their lives, while over 350,000 were left homeless. Entire communities saw homes, farms and futures washed away.
This disaster was driven by a literal ‘perfect storm’ of weather systems converging; peak monsoon rainfall, La Niña conditions and Cyclone Senyar. But weather alone does not explain the scale of destruction, or its disparity between different locations. What really made the difference was the condition of the surrounding landscape.
Where forests had been degraded, watersheds failed. Rain rushed unimpeded into rivers, which swelled with sediment and burst their banks, leading to catastrophic flooding and deadly logjams. Weather may have been the trigger, but deforestation is the smoking gun of this tragedy.
Though the villages partnered with OIC and the Rimba Collective were relatively unscathed by the flooding, Syafrizaldi spent November and December 2025 travelling around Aceh delivering aid to displaced families in hard-hit areas beyond the project boundaries, while anxiously waiting to hear news from his own daughter in Banda Aceh.
On his travels, he saw first-hand the consequences of climate-related weather events on local communities. But in places where surrounding forests remained intact, the story was markedly different, demonstrating how proper land‑use decisions, combined with within‑value‑chain action can effectively reduce risk. In this article, we investigate the cause of the flooding, and examine the role forest protection played in mitigating its impacts.
Cause and Effect: What Happened in North Sumatra?
In late November and early December 2025, heavy rainfall swept across Aceh, North Sumatra and West Sumatra, triggering floods and landslides. More than 1,200 people lost their lives, while over 350,000 were left homeless. Entire communities saw homes, farms and futures washed away.
This disaster was driven by a literal ‘perfect storm’ of weather systems converging; peak monsoon rainfall, La Niña conditions and Cyclone Senyar. But weather alone does not explain the scale of destruction, or its disparity between different locations. What really made the difference was the condition of the surrounding landscape.
Where forests had been degraded, watersheds failed. Rain rushed unimpeded into rivers, which swelled with sediment and burst their banks, leading to catastrophic flooding and deadly logjams. Weather may have been the trigger, but deforestation is the smoking gun of this tragedy.
The relationship between deforestation and flood damage is not coincidental correlation, but a scientifically predictable causal relationship.
Syafrizaldi Jpang
Executive Director of the Orangutan Information Centre
The Value of Protection vs. the Cost of Inaction
Syafrizaldi has his own ideas about what caused the flooding. “I see the great floods in Sumatra not merely as natural disasters,” he says, “but as the accumulation of decades of wrong land-use decisions.” He insists the right decision now is to invest in forests and prevent recurrence. As he explains, “protecting remaining forests is far cheaper and more effective than repairing damage afterwards.”
To that end, Syafrizaldi views the OIC’s ongoing partnership with the Rimba Collective as an effective mechanism for this investment; the foundation for recovery in the immediate aftermath, and the building blocks of future resilience. With the right support, he believes local knowledge can be key to both processes, and says partnership with the Rimba Collective can act as a capacity multiplier:
“Local communities—those who live, work and depend on the landscape—can become frontline actors in monitoring, protection and rapid response. I also believe this partnership must continue to mature by building long-term local capacity. This ensures conservation is not vulnerable to project, donor or leadership changes, but becomes a rooted practice.”
Forest Protection is Disaster Prevention
The village of Jambo Papeun – a Rimba Collective project in South Aceh, operated by BITRA Indonesia – is one location where both forest protection and capacity building are beginning to take shape. Here, communities endured the same rainfall as surrounding areas, but the flooding was noticeably less severe.
Dyah Lestari is BITRA’s Forest Management and Biodiversity Specialist. She explains how protecting the surrounding forest may have also saved her community: “tree roots bind soil and absorb water, reducing surface runoff that causes flooding, while tree canopies filter rainfall, preventing erosion.”
Without our programmes in place, Jambo Papeun and the surrounding areas would have been more seriously affected. These project activities not only protect forests – they can also save lives.
Dyah Lestari
Forest Management and Biodiversity Specialist, BITRA Indonesia
The recent storm was not an isolated event. Long-term residents of Jambo Papeun Village have witnessed changes to the landscape over generations, and seen their fair share of floods. Many have noticed the ecosystem has begun to stabilise since BITRA began working to support the protection of local forest and river systems.
As one community member noted in the wake of the December rains: “Before forest patrols and other forest protection activities implemented by BITRA began, every heavy downpour like this would raise the river's water level, carrying logs with it. But now, we can see for ourselves that not a single log was carried away by the river current.”
Mitigating Nature Degradation & Climate Risk Through Forest Protection
Dyah and Syafrizaldi paint a picture of communities in need; not of rescue, but support. They have seen how people come together in times of crisis, and insist that when these frontline projects are empowered to protect their forests, the forests in turn can effectively protect those communities from the worst impacts of extreme weather.
Villages like Jambo Papeun offer a model for effective climate mitigation strategies. Here and elsewhere, long-term, large-scale investments are being channelled into community-led conservation efforts by skilled operators like BITRA and the OIC. By equipping local people with the tools they need to restore nature’s life support systems, these projects are safeguarding vital watersheds from degradation and strengthening nature’s protective capacity, while sustainably utilising natural capital and securing its supply.
What Sumatra needs now is more proactive, large-scale and long-term funding to standardise early-stage forest protection/preservation and build the foundations for future resilience. The recent floods delivered a warning. But they also showed us the way forward. Now is the moment to walk that road together with the Rimba Collective Project Operators and the communities they represent. As Syafrizaldi Jpang puts it:
Conservation is about nurturing relationships: between forest and water, wildlife and humans, science and policy. Partnerships based on trust, equality and long-term vision not only help us recover today—they prepare landscapes and communities to endure tomorrow.
Syafrizaldi Jpang
Executive Director of the Orangutan Information Centre
Scrutiny, Accountability & Credibility
The importance of following this path could not be clearer, both in terms of the environmental imperative and the regulatory necessity. This January, in response to the floods, the Indonesian government revoked the permits of 28 forestry, plantation, mining and energy companies found to have violated environmental regulations designed to prevent deforestation, watershed degradation and land instability. Their investigations drew a line between poor land management – including illegal clearing, peatland drainage and failure to maintain riparian buffers – to increased flood risk and sedimentation. The revoked concessions reportedly covered around one million hectares, sending a clear message that environmental non-compliance can trigger immediate regulatory consequences, including loss of operating rights.
This response underscores the material risks that landscape degradation poses, not only to ecosystems and communities, but also to companies operating within (or sourcing from) these regions. Flooding disrupted transport routes, damaged infrastructure and halted production across supply chains, demonstrating how environmental mismanagement upstream can translate into operational, financial and reputational risks downstream.
For the Rimba Collective, the Sumatra floods illustrate exactly why pursuing within value chain mitigation (WVCM) is essential for companies sourcing palm oil and other commodities from these landscapes. By investing directly in forest protection, restoration and community-led stewardship within their own sourcing regions, companies can reduce systemic risks that threaten both supply security and their licence to operate. Environmental degradation upstream is already translating directly into operational, financial and reputational risk downstream. Companies can no longer offset their way out of systemic climate and nature risk; they must invest directly in the landscapes that underpin their supply chains.
Closing: What the Floods Reveal About Nature Finance
Syafrizaldi’s daughter turned out to be ok. Like many, she had been cut off by the flooding with no access to phone or internet, but thankfully was safe. Thousands more in Aceh and North Sumatra were not so lucky. The flooding delivered a warning from nature, along with valuable lessons to be learned.
First, ecosystem service outcomes are not only measured in hectare coverage, trees planted or emissions avoided; the true value of a healthy, intact forest can be seen in the lived realities of people who monitor wildlife, work the land and depend on nature for their livelihoods. Second, it is these communities who feel the impacts of climate change and suffer the consequences of deforestation; through the Rimba Collective, they can also strengthen the protection that nature provides.
The Sumatra floods demonstrate how the extent of climate and nature risk depends on the land‑use decisions made within production landscapes. Where forests are degraded, extreme weather leads to loss of life, infrastructure damage and supply‑chain disruption; conversely, where forests are protected, communities and landscapes prove to be more resilient under the same conditions.
For companies sourcing from these regions, this distinction is decisive. Risk cannot be managed remotely, offset elsewhere, or deferred through short‑term measures; it must be reduced where it arises. The experience of Sumatra makes clear that long‑term, within‑value‑chain forest protection is no longer a complementary action – it is a baseline requirement for resilience, regulatory credibility and licence to operate.
About the Rimba Collective
The Rimba Collective is an innovative, 25‑year collaboration between leading consumer goods manufacturers, NGOs and forest‑dependent communities in Southeast Asia. It aims to protect critical landscapes, strengthen livelihoods and conserve biodiversity through a portfolio of high‑quality conservation, restoration and community‑led projects embedded within palm‑oil supply chains.
As of the end of 2025, the Rimba Collective portfolio spans over 466,000 hectares of forest landscapes under conservation and restoration across Southeast Asia, with continued growth toward a collective ambition of 650,000 hectares by the end of 2027. Through long‑term, performance‑based partnerships, the initiative delivers durable benefits for nature, climate and forest‑dependent communities, contributing to more resilient sourcing landscapes over decades.
To find out more, and to join the Rimba Collective, please get in touch.