David Akana, North Sumatra, Indonesia – Indonesia's environment ministry on Dec. 6 suspended private sector activity in a crucial high conservation value rainforest as rescuers continued working through three Sumatran provinces following a highly unusual and catastrophic tropical cyclone.
"We've identified at least three main sources exacerbating the flooding: industrial forestry plantations, massive hydropower development and gold mining activities in the Batang Toru watershed," Environment Minister Hanif Faisol Nurofiq said Dec. 6. "All of these have contributed significantly to the pressure on the environment."
Batang Toru is an old-growth Sumatran rainforest home to the Tapanauli orangutan (Pongo tapanuliensis), the world's most endangered species of ape.
The minister said the operating permits for three companies would be suspended pending a review following an aerial survey of Batang Toru, one of the areas of Sumatra worst affected by a rare tropical cyclone.
Glenn Hurowitz, the chief executive of Mighty Earth, a nonprofit that has campaigned for protection of the Batang Toru ecosystem, said Minister Hanif "deserves thanks from around the world for taking decisive action to protect the Batang Toru ecosystem and local communities... Suspending the operations of companies driving deforestation is a vital step to avoid a repeat of this catastrophe."
Hanif was joined over the weekend on a helicopter flyover by the environment ministry's deputy director of the law enforcement division, which has powers to conduct criminal investigations.
"We'll assess the damage, assess the legal aspects, and we won't rule out the possibility of criminal proceedings if violations are found that worsened the disaster," the minister said.
Two days earlier, on Dec. 4, Forestry Minister Raja Juli Antoni said the forestry ministry would suspend permits covering around 750,000 hectares (1.9 million acres), an area 12 times larger than Chicago.
Separately, the energy and mining minister, Bahlil Lahadalia, said his office would determine any link between mining and the catastrophe – the Jardine Matheson-controlled Martabe gold mine, one of the world's largest gold mines, is located in Batang Toru.
On Nov. 27, a day after the cyclone made landfall over Sumatra, the group said it would expand operations and develop a new pit in Tor Ulu Ala, located "to the north of the current footprint" of the Martabe mine.
Civil society organizations have also raised the case of oil palm operations, including areas operated by PT Sago Nauli and PTPN III in Batang Toru.
On Dec. 8, the governor of North Sumatra province, Bobby Nasution, said road access remained blocked to 13 subdistricts in the province, including areas of Batang Toru, but these areas could be reached on foot and aid deliveries were underway.
Rare event
Indonesia's meteorology agency, the BMKG, said the severity of the rainfall may have reflected an interaction between two tropical cyclones.
Tropical Cyclone Koto formed over the Philippines on Nov. 23, while Cyclone Senyar began over the Malacca Strait, which separates Sumatra from Peninsular Malaysia and Singapore.
Meteorologists said cyclones over Sumatra were rare and a combination of storms rarer still, but a precise link to climate change could not yet be proved.
"We can't just leave it as it's the rain or the climate to blame," Eko Teguh Paripurno at University of National Development "Veteran" Yogyakarta in Java, told Mongabay Indonesia.
Eko called for greater scientific rigor in determining carrying capacity and resilience of landscapes, similar to how scientists attribute liability for fires on plantation company concessions.
When Cyclone Senyar made landfall over northern Sumatra in the early hours of Nov. 26, the meteorology reading for three-hour precipitation accumulation exceeded 130 millimeters (5.1 inches) of rain over communities around the coastal city of Lhokseumawe in the Special Autonomous Region of Aceh.
That is more rain in three hours than the U.K. receives on average during its wettest month of the year.
Scientists say climate change should make tropical cyclones less frequent but more intense. The volume of rainfall over Sumatra indicates some of the worst flooding in perhaps decades.
At least 961 were confirmed dead by Dec. 9 after waves of water carrying rocks and timber careened down hillsides into communities.
The head of Indonesia's disaster agency, Suharyanto, told a cabinet meeting that took place in Aceh on Dec. 7 that reconstruction costs would exceed $3 billion.