The Bureau of Meteorology (BOM) says Australia is under an ‘El Niño watch’.
It means there is about a 50% chance an El Niño ‘event’ will occur this year, likely bringing drier and hotter weather along with it.
What exactly is an El Niño event? Here’s what you need to know.
How does Australia’s weather change?
Australia’s climate is shaped by several natural phenomena.
Perhaps the most significant of these is called the ‘El Niño-Southern Oscillation’ (ENSO).
ENSO is roughly an eight-year cycle affecting the atmosphere and ocean temperatures in the Pacific.
It can produce two extremes: El Niño and La Niña.
What’s the difference between El Niño and La Niña?
Here’s the simplest version of the story.
La Niña happens when the water on our end of the Pacific is unusually warm, bringing with it more rain.
El Niño happens when the water on the other end of the Pacific is warm and pulls the rain from Australia’s end, making Australia drier and hotter.
It’s not automatic. Climate experts monitor ocean conditions to detect when either event is likely, and how severe it might be.
When will El Niño start?
Right now, we are in ‘neutral’ territory – neither El Niño nor La Niña.
However, many of the signs that point towards an El Niño are present. All of the climate models the BOM consults suggest that an El Niño event will occur later this year.
The BOM’s own model predicts a relatively severe El Niño.
What does El Nino mean?
The most direct consequence of El Niño is less rainfall through spring, winter and summer, especially on the east coast.
This can also have a knock-on effect to higher average temperatures because there is less cloud cover. As well as higher average temperatures, there can also be more individual days of very extreme heat.
This combination has fuelled some of Australia’s worst drought and bushfire seasons in previous years.
