Indonesia’s peatlands face growing flood risks amid widespread degradation

Watchdog Pantau Gambut says at least 25% of country’s peatlands are highly vulnerable to flooding 

JAKARTA, Indonesia (MNTV) — Nearly half of Indonesia’s peatlands are vulnerable to flooding due to degradation caused by unchecked exploitation, with 6 million hectares (15 million acres) — an area twice the size of Belgium — classified as highly vulnerable, Mongabay news portal reports.

Peatland watchdog Pantau Gambut examined three peatland-rich regions of Indonesia: the island of Sumatra; the Indonesian portion of the island of Borneo, known as Kalimantan; and the Indonesian half of the island of New Guinea, known as Papua.

Each region has distinct topographical and climate characteristics. Kalimantan features lowland coastal peat with high rainfall. Sumatra has both inland and coastal peatlands. Papua is the most complex, with extremely high rainfall and peatlands spanning inland, coastal and mountainous areas. 

The report found that at least 25% of Indonesia’s peatlands are highly vulnerable to flooding, with another 18% classified as moderately vulnerable. This means 43% of the country’s 24 million hectares (59 million acres) of peatlands are at risk, while only 57% have low vulnerability.

Peatlands, as part of wetland ecosystems, are naturally waterlogged and capable of absorbing far more water than mineral soils. Peat can retain 100-1,300% of its dry weight in water, while mineral soils typically absorb only 20-30%. However, once degraded, peatlands lose their ability to retain water effectively.

This phenomenon, known as irreversible drying, turns standing water into uncontrolled runoff, leading to flooding.

“The floods occurring are not a natural cycle commonly found in peatland ecosystems,” said Wahyu Perdana, advocacy and campaign manager at Pantau Gambut. “These floods result from peatland degradation due to improper land use and the mismanagement of peatland functions.”

Another major contributor to peat flooding is subsidence — the compaction of peat, according to Kitso Kusin, a peat researcher at the University of Palangka Raya in Central Kalimantan province.

When peat is drained, usually by the digging of canals for industrial agriculture, it compacts, reducing its water absorption capacity, Kitso said. The dried-out layer of peat that remains is highly flammable, and it’s this one-two punch of subsidence and fire that’s historically been a key driver of peatland destruction across Indonesia.