Indonesia is burning peatlands. Here’s why that makes the haze even worse than normal fires.

Smoldering peat in Sumatra and Kalimantan is behind the poisonous smog.
Reuters/Rony Muharrman/Antara Foto/Files
  • Toxic haze has blanketed Singapore, Malaysia and Indonesia for the past fortnight.

  • The haze comes mostly from peatland burned by local farmers.

  • Peatland is a waterlogged forest that contains high amounts of carbon and doesn’t burn easily.

  • Farmers drain out the water and burn the carbon-filled forest.

  • The high carbon content creates haze that is far thicker and more poisonous than smoke from a normal wildfire.

  • Unlike regular forest fires, it isn’t put out easily and can go on for months.

It’s haze season again – with the toxic smog blanketing Singapore, Malaysia and Indonesia clocking in at unhealthy and even hazardous PSI levels for over a week.

Apart from some areas of Malaysia, which recorded forest fires during the haze period, burning peatlands in Indonesia’s provinces of Sumatra and Kalimantan are 90 per cent responsible for the haze, according to the World Bank.

These are the exact same areas the worst haze is coming from.

Thick, noxious smoke from Kalimantan, as seen from space on Sept 14.
NASA Earth Observatory/Joshua Stevens

Over 14,000 hotspots were recorded in the two areas – most of which were peatland, the NASA Earth Observatory said.

The number of high-confidence hotspots recorded in Sumatra and Kalimantan for the month of September shot up to 14,412. It was 68 in January.
ASEAN Specialised Meteorological Centre 

Peatlands – which are found on 3 per cent of the Earth’s surface, including places like Indonesia, Malaysia and even the Arctic – are swamps that form when a forest floor is continuously saturated with water.

Sponge-like peat sucks up water quickly. It contains slowly decaying plant material like dead leaves and wood, which can accumulate up to 20 metres thick.

Unlike other types of terrain, peatland can permanently lock away carbon – which was previously absorbed by dead leaves during photosynthesis -from the atmosphere, according to the International Union for Conservation of Nature.

Tropical peat contains 10 times more carbon than regular mineral soil, according to a paper research on peatlands in Indonesia by local scientists.

Burned peatland in Indonesia releases more smoke than regular forest fires due to the carbon content of peat.

According to a Wired report, dried peat eventually hardens into coal – which is extremely flammable and contains very high amounts of carbon and toxins.

Luckily – because it is wet – peat does not catch fire naturally. Even if it did, the rainfall and humidity in Indonesia stop peatland fires from spreading, according to the United Nations’ Food and Agriculture Organization (FAO).

So why does Indonesia burn so badly? This is because farmers drain squishy peatlands before setting them on fire, meaning all their watery protection is lost, FAO said.


This also causes the thick, carbon-rich layer to dry and harden, meaning fires can continue for months, even if the flames on the surface have been put out.

The only way to extinguish them is to re-flood the area.

As carbon burns, the smoke created is much thicker and way more poisonous than regular forest fires,NASA Earth Observatory said.

The carbon is also the source of fine particulate matter, the stuff that makes haze bad for health.

Carbon emissions in Indonesia are concentrated in peatlands, as seen in this NASA vizualisation on Sept 17.
NASA Earth Observatory/Joshua Stevens

These toxic particles include sulphur dioxide, ozone, nitrogen dioxide and carbon monoxide – which enter a person’s lungs and bloodstream when the haze is breathed in.

This can cause eye, heart, skin and respiratory problems, according to Singapore’s health ministry.

Apart from toxic gas that makes you sick, burning peatland (essentially concentrated coal) also releases insane amounts of greenhouse gases into the environment.

So far, this year’s Indonesia haze has caused nearly 110 million tons of carbon dioxide to enter the atmosphere, according to environmental site Mongabay.

That’s the equivalent of using 22 million cars for a period of one year.

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