National

 View Only
Back to discussions
Expand all | Collapse all

Weather experts not convinced El Nino is guaranteed yet

  • 1.  Weather experts not convinced El Nino is guaranteed yet

    Posted 19-06-2023 08:23

    Our weather experts not convinced El Nino is guaranteed yet, or how long it might last

    The Bureau of Meteorology has announced the end of the 2022-23 La Nina weather pattern but declared a 50 per cent chance of El Nino - bringing hot and dry conditions to Australia - later in the year.

    Some of Australia's leading weather experts say the forecast arrival of an El Nino in the next few months is no cause for weather panic just yet.

    Australia's leading science agency CSIRO polled its principal weather researchers to further explain the Bureau of Meteorology's upgraded El Nino prediction from "watch" to "alert", meaning the drying weather pattern is now more likely than not.

    After three boom years for farm production across Australia, the sudden reversal from La Nina to El Nino has many people worried.

    CSIRO senior research scientist Nandini Ramesh said it was still difficult to say with confidence whether the predicted El Nino would be a high-magnitude event.

    "International forecasts suggest a moderate-strength El Nino event is the most likely outcome, followed by a high-strength El Nino event,' Dr Ramesh said.

    "The uncertainty about this comes from the atmosphere, which has had a relatively muted response thus far to the now well-established warm sea surface temperatures. 

    "How strong the El Nino event gets now depends on how the atmosphere evolves over the next few months."

    CSIRO's ocean dynamics team leader Chris Chapman said it was not known exactly where and how the strongest sea surface temperatures (SSTs) will pop up until an El Nino event gets underway.

    "However, given the currently high SSTs in the equatorial Pacific, an additional 'nudge' from El Nino could see record high SSTs in some regions," Dr Chapman said.

    "The response of equatorial Pacific sea surface temperatures to El Nino depends on where you are and the 'flavour' of El Nino." 

    Responding to a question on whether climate change is making El Nino events worse, CSIRO climate intelligence director Jaci Brown said the atmosphere is warmer due to climate change and so hot, dry conditions associated with El Nino are exacerbated.

    "Whether El Ninos are changed or made worse by climate change is a more complex question."

    Dr Brown was also asked whether after three La Nina's in a row, Australia could not get three El Ninos in a row?

    "A more pressing question is whether we are about to head into a multi-year drought which is associated with many factors, not just El Nino," Dr Brown said.

    "At this stage our climate models cannot give us reliable forecast information beyond about six months. But we have seen multi-year droughts before and we will see them again." 

    Dr Ramesh said: "This is something we have not seen before; the longest El Ninos have been about two years long. La Nina and El Nino are not perfect mirror images of each other, and La Nina events often last longer than El Nino events do."

    Drought Resiliance Mission lead Dr Graham Bonnett said El Nino events don't always lead to lower rainfall or droughts.

    "We notice drought impacts more when relatively low rainfall years translate to poor crop and pasture growth, or prolonged dry years see water storage dams run low or empty.

    "The timing of lower rainfall translating to poorer crop and pasture growth will depend on the amount of starting soil moisture."

    Continue reading on Central Western Daily

    Source: Central Western Daily; Chris McLennan


    #ClimateChangeImpacts

    ------------------------------
    Emily Mason
    Sydney NSW
    ------------------------------