Singapore faces the risk of an incoming wave of transboundary haze in the second half of the year. But are you cognisant of the causes of haze? The onset of haze in Singapore is primarily triggered by the burning of huge swathes of carbon-rich peatlands in Borneo and Sumatra Islands of Indonesia for palm oil and pulpwood conversion. Between June and September 2023, Singapore typically experiences the Southwest monsoon, meaning that particulate matter (PM) released from the burning peatlands in Riau could be blown over to Singapore.
To understand why peatlands play such a pivotal role in SG transboundary haze, we must first know what they are. Peatlands are wetland ecosystems that are naturally waterlogged and contain large amounts of nutrients due to their slow decomposition rates. But what really makes them such a contentious matter is their high carbon carrying capacity. To pave the way for irrigation-dependent plantations, peatlands are typically canalised and drained by plantation owners, leaving the peat matter dry and exposed to oxygen and highly combustible. In addition, increasing market demands for these agricultural commodities motivates farmers to clear peatlands using slash-and-burn practices. Therefore, when drained peatlands burn via natural means or human-driven deforestation, large amounts of sequestered carbon is released in the form of soot, carbon dioxide and other particulate matter. These PM could be carried by monsoon winds over to Singapore. The duration of transboundary haze in Singapore is hence dependent on the proximity of burning peatlands and direction of monsoon winds.
Moreover, peatlands have the inherent ability to burn underground, also known as smouldering, which can go on for months and are often difficult to extinguish. These factors lead to the prolonged periods of fire, and sequentially haze episodes that we experience in Singapore. It is pertinent that locals see the correlation between peatland degradation and transboundary haze in Singapore, so that we can better protect ourselves against the multi-faceted problems of haze.