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'Wild weather' not from climate change

FLASH FLOODS: Downpours over parts of western Singapore in February last year led to floods along Holland Avenue and Ayer Rajah Expressway near the Clementi Road exit.


    Jun 24, 2014

    'Wild weather' not from climate change

    IF YOU think that global warming is behind the erratic weather patterns here, such as the recent heavy rainfall or dry spell, you may be wrong.

    This is because climate change here due to global warming may only be seen a century from now, said Chris Gordon, director of Centre for Climate Research Singapore, which is part of the National Environment Agency's (NEA's) Meteorological Service yesterday.

    Global warming is caused by the release of greenhouse gases from human activity. Experts like Dr Gordon say they "cannot definitively answer" what could be the culprit for intense weather patterns such as the heavy rainfall, which led to recent flash floods that have wreaked havoc in parts of Singapore, which included shutting down the Ayer Rajah Expressway last September.

    "So it is true that in this region, climate change will also project increasing extreme rainfall, but that is in 100 years' time."

    In fact, the current weather changes could be "just a natural variation of the climate", he pointed out, adding that urbanisation may also be a cause, which is the case for other major cities in the region as well.

    "(This is because) the actual change in the surface characteristics of the island can affect the convective thunderstorms that we've been having," noted Dr Gordon.

    Apart from the intense rainfall, February was Singapore's driest month in nearly 150 years, and the windiest in three decades, according to the NEA.

    Going forward, there is "no reason to expect" that Singapore will see more of such conditions but, at the same time, there are also limitations in the current climate models.

    But as Singapore is in the Tropics, it makes it more difficult to accurately predict the weather.

    This is because tropical weather systems have unique features such as thunderstorms caused by convections, a process where hot moist air rises and forms clouds.

    Currently, the accuracy rate of the three-hour forecast is about 90 per cent.

    The lead time for a heavy rainfall prediction is about 30 minutes at best, but this could also be improved to more than an hour.

    Wong Chin Ling, director-general of the Meteorological Service, said: "The challenge for us... is that there is always this demand for information about where exactly is heavy rainfall going to fall, and how much is this.

    "These are very difficult questions for us to address but we are looking into a very high-resolution model and making use of latest technology to help us provide a more reliable forecast of heavy rainfall."