Deforestation in Aceh, North Sumatra, and West Sumatra has surged threefold over the last ten months, according to data from MapBiomas Indonesia. This alarming increase is believed to be a significant contributing factor to the devastating floods that have recently engulfed these three provinces on Sumatra island. The catastrophic impact is profound: the National Disaster Management Agency (BNPB) reported that as of December 3, 2025, at 3:30 PM WIB, the death toll from flash floods across Sumatra had reached 770, with an additional 623 people still missing.
Timer Manurung, the Head of the MapBiomas Indonesia Team, highlighted the dramatic shift in Aceh. In 2024, deforestation in Aceh was below 10,000 hectares. However, by October 2025, this figure had escalated to nearly 30,000 hectares, positioning Aceh among the provinces experiencing the highest forest loss in Indonesia. An analysis of land cover changes in Aceh between 2014 and 2024 by MapBiomas further reveals a reduction in forest area from 3,413,709 hectares to 3,395,970 hectares. Concurrently, palm oil plantations saw a substantial expansion, growing from 455,250 hectares to 628,697 hectares.
West Sumatra, previously not listed among provinces with the highest deforestation rates, now ranks fourth, with approximately 30,000 hectares of forest loss. Over the past decade, West Sumatra has undergone considerable land cover transformation. Its forest area diminished from 2,424,687 hectares to 2,400,294 hectares, clearly indicating widespread deforestation. Parallel to this, palm oil plantation areas expanded from 515,253 hectares to 569,183 hectares, replacing natural forest landscapes.
Similarly, North Sumatra witnessed a sharp rise in deforestation, from an initial estimate of 7,000 hectares to almost 20,000 hectares. This trend is consistent with land cover changes observed in the province over the last decade, where palm oil plantations expanded significantly from 1,972,640 hectares to 2,115,976 hectares. In contrast, other agricultural lands in North Sumatra decreased from 1,405,473 hectares to 1,213,595 hectares, indicating a shift in land use priorities at the expense of natural ecosystems.
“Hopefully, this serves as a final warning, signaling how imperative it is for us to cease the destruction of our natural forests and to restore the areas that have already been damaged,” stated Timer Manurung during the launch of MapBiomas Alerta in Jakarta on Wednesday, December 3. His powerful message underscores the urgency of conservation efforts and sets the stage for innovative solutions in environmental monitoring.
MapBiomas Alerta, Deforestation Monitoring System
During the same event, MapBiomas Indonesia officially unveiled MapBiomas Alerta, a sophisticated deforestation validation and publication system built on high-resolution satellite imagery. This pioneering platform is engineered to enhance the reliability of deforestation data across Indonesia and provide actionable, ready-to-use reports, thereby significantly bolstering remote oversight and environmental protection efforts. “Through solid data, we are offering a concrete solution. We firmly believe that our economy and welfare can be built without compromising our forests,” Timer emphasized, highlighting the vision behind the new system.
The Alerta platform was initially developed in Brazil in 2018 by the co-creators of MapBiomas. It has since undergone continuous refinement through collaborative efforts with government agencies and providers of deforestation alerts. In Indonesia, the MapBiomas network initiated the development of this localized platform in 2024. A consortium of non-governmental organizations forms the MapBiomas network in Indonesia, including Auriga Nusantara, Haka, HaKi, Genesis, Save Our Borneo, Sampan Kalimantan, Jerat Papua, and Woods and Wayside International, all dedicated to environmental stewardship.
To guarantee the utmost data validity, Alerta meticulously processes deforestation areas by validating every deforestation alert received from the Global Land Analysis and Discovery (GLAD) system since January 2021. Each indication of deforestation is meticulously re-mapped using high-resolution satellite imagery to ensure superior accuracy. The comprehensive information provided includes details on the parties responsible for land clearing, the exact area affected, the timing of the incident, and the precise location of deforestation based on administrative boundaries, forest areas, permits, and other relevant land categories.
This critical data is updated weekly and made publicly accessible, fostering unparalleled transparency. Beyond serving as a vital information source, this openness plays a crucial role in empowering public oversight. By providing reliable and up-to-date information, MapBiomas Alerta enables citizens and organizations to monitor environmental changes and advocate for accountability effectively.
Novel Baswedan, Deputy Head of the National Police Special Task Force, remarked that the data within MapBiomas Alerta could serve as compelling evidence for reporting fraud in cases of environmental exploitation. This potential is rooted in Article 5 of the Electronic Information and Transactions Law (UU ITE), which acknowledges the use of electronic data as legal evidence. Novel clarified, “While a screenshot of the platform itself cannot be direct evidence, if the data is officially requested and provided, it certainly can be utilized, and we hope this contributes to improving law enforcement.”
Summary
Deforestation in Aceh, North Sumatra, and West Sumatra surged threefold in the last ten months, a significant factor in recent devastating floods across Sumatra. These floods resulted in 770 deaths and 623 missing by early December 2025. Aceh and West Sumatra each experienced approximately 30,000 hectares of forest loss, while North Sumatra saw nearly 20,000 hectares disappear, primarily due to the expansion of palm oil plantations replacing natural forests.
MapBiomas Indonesia also launched “MapBiomas Alerta,” a sophisticated system utilizing high-resolution satellite imagery for validating and publishing deforestation data. This platform provides detailed, weekly updated, and publicly accessible information on deforestation areas, timing, and responsible parties, enhancing transparency and environmental oversight. The data generated by MapBiomas Alerta is intended to bolster environmental protection efforts and can potentially serve as legal evidence in cases of environmental exploitation fraud.
