Risk of transboundary haze
Asked if the forecast warmer than usual temperatures in 2024 would increase the possibility of transboundary haze in South-east Asia, experts said the risk of forest fires in the region depend on numerous factors beyond just temperatures.
NTU’s Prof Yim said: “A warmer-than-usual situation alone may not increase the risk of transboundary haze, but the situations of drought, warmth, and favourable wind together are very likely to facilitate transboundary haze pollution in Singapore.”
The MSS spokeswoman said seasonal climate models are not predicting that another El Nino will form in 2024.
“The southern Asean region is expected to be less dry during the traditional dry season in June to October 2024, than in the corresponding period in 2023, when there were El Nino conditions and a positive Indian Ocean Dipole,” the MSS spokeswoman added.
She was referring to the positive Indian Ocean Dipole (IOD) conditions that beset Singapore in the second half of 2023, contributing to warmer-than-usual temperatures that year.
Similar to El Nino, a positive IOD brings warmer weather to Singapore due to atmospheric and sea surface temperature variations across the Indian Ocean. In 2023, Singapore experienced a “double whammy” of climate phenomena that nudged up average temperatures.
The MSS spokeswoman added that periods of dry weather can still be expected between June and October 2024.
“(This) may result in transboundary haze if fires develop in the nearby region and prevailing winds blow the smoke plumes towards Singapore,” she said.
Dr Koh Tieh Yong, co-chair of the Working Group for Asian-Australian Monsoon and World Climate Research Programme, noted that the risk of transboundary haze depends on more than just meteorological factors.
“Every year, the risk of transboundary haze depends to a larger extent on the human activities on the ground: land clearance by burning, preventive irrigation of cleared land by local authorities, on-site policing against illegal agricultural practices,” he said.