The recent widespread flooding across northern Sumatra is primarily a consequence of extensive forest conversion over the past several years, according to Deputy Minister of Public Works, Diana Kusumastuti. This significant alteration of forest areas has severely diminished the land’s capacity to absorb water, rendering it unable to withstand the heavy rainfall that has persisted since the beginning of the week.
“One of the primary causes of the deluge in Aceh, North Sumatra, and West Sumatra is the transformation of what were once lush forests into agricultural lands, residential areas, and other developments. This fundamental shift in land use is directly contributing to the severe flooding we are witnessing,” Diana explained from her office in Jakarta on Friday (November 28).
Supporting this assessment, data from Global Forest Watch reveals an alarming trend: Aceh, North Sumatra, and West Sumatra collectively lost over 300,000 hectares of primary wet forest between 2022 and 2024. The underlying reasons for this extensive forest conversion vary by region. In Aceh and West Sumatra, the primary driver has been the exploitation of timber for commodity use, while in North Sumatra, the expansion of settlements and infrastructure development are the dominant factors.
More specifically, North Sumatra has endured the loss of a staggering 390,000 hectares of primary wet forest, which constitutes 25% of the region’s total tree cover loss during the specified period. Overall, the total primary wet forest area in North Sumatra has shrunk by a significant 19% within this timeframe.
Similarly, West Sumatra has seen 320,000 hectares of its primary wet forest disappear, representing a substantial 44% of its total tree cover loss over the same period. The overall primary wet forest area in West Sumatra has decreased by 14%.
Lastly, Aceh reported a loss of 320,000 hectares of primary wet forest, contributing 38% to its total tree cover loss within the same timeframe. The total primary wet forest area in Aceh experienced a 9% reduction.
Offering an additional perspective, Uli Artha, Campaigner for Forests and Plantations at the Indonesian Forum for the Environment (WALHI), strongly asserts that extreme weather is not the root cause of these disasters. Instead, she highlights that the profound impact stems from the extensive loss of forest cover, directly attributed to the activities of extractive industries.
“The fundamental problem lies in the escalating ecological vulnerability of these regions,” Uli stated in an interview with Katadata.co.id on Friday (November 28).
According to Artha, this ecological vulnerability is exacerbated by the proliferation of permits granted to extractive industries, which systematically erode crucial ecosystem areas. She specifically points to the Bukit Barisan mountain range, a vital landscape stretching across Sumatra, describing its ecological function as precarious. Disturbingly, the management of this critical region is deemed highly problematic.
“In the context of Sumatra, the Bukit Barisan landscape is an ecological zone with both vital and precarious functions. Therefore, if this landscape is mismanaged by the government, it will inevitably lead to significant repercussions in the form of ecological disasters,” Uli warned.
Summary
The widespread flooding across Aceh, North Sumatra, and West Sumatra is primarily a consequence of extensive forest conversion, according to Deputy Minister of Public Works, Diana Kusumastuti. The transformation of forests into agricultural lands and residential areas has severely diminished the land’s capacity to absorb water, directly contributing to severe deluges during persistent heavy rainfall.
Data from Global Forest Watch shows that these regions collectively lost over 300,000 hectares of primary wet forest between 2022 and 2024, driven by timber exploitation in Aceh and West Sumatra, and settlements in North Sumatra. The Indonesian Forum for the Environment (WALHI) further asserts that extensive forest loss due to extractive industries, and not extreme weather, is the root cause, leading to escalating ecological vulnerability in these areas.
