El Nino — the sibling of the dreaded La Nina climate driver — has arrived and experts warn it will likely make 2024 the “hottest year in history”.
US scientists declared this week that the natural weather event had begun in the Pacific Ocean, warning that it would likely add to an already warming planet.
The phenomenon is the most powerful fluctuation in the climate system anywhere on Earth. The scientists feared it will affect world weather, potentially bringing heavy rain to the southern US and weakening the Indian monsoon season.
In Australia, it’s likely mean three things: heat, drought and fire.
“It’s ramping up now. There have been signs in our predictions for several months, but it’s really looking like it (El Nino) will peak at the end of this year in terms of its intensity,” said Adam Scaife, head of long-range predictions at the UK Met Office.
“A new record for global temperature next year is definitely plausible. It depends how big the El Nino turns out to be. A big El Nino at the end of this year gives a high chance that we will have a new record global temperature in 2024.”
Record warm years — including 2016, the world’s hottest on record — usually happen the year after a powerful El Nino event.
What is El Nino?
Marked by warmer-than-average sea surface temperatures in a key area of the central and eastern Pacific Ocean near the equator called “Nino 3.4”, the weather pattern last occurred in 2018-19, and takes place every two to seven years on average.
El Nino, meaning “little boy” in Spanish, is the warm phase of the El Nino-Southern Oscillation climate driver. La Nina, meaning “little girl,” is its colder counterpart, where sea surface temperatures at Nino 3.4 are lower than normal
“Depending on its strength, El Nino can cause a range of impacts, such as increasing the risk of heavy rainfall and droughts in certain locations around the world,” said NOAA climate scientist Michelle L’Heureux.
“Climate change can exacerbate or mitigate certain impacts related to El Nino. For example, El Nino could lead to new records for temperatures, particularly in areas that already experience above-average temperatures during El Nino,” she added.
What does El Nino mean for Australia?
El Nino is likely to mean a grim weather forecast for Australia — turning the recent La Nina conditions on their head and bringing scorching conditions that could potentially lead to drought, bushfires and maximum temperature records.
Most of the warmest years on record have occurred during or immediately after El Ninos, and scientists are concerned that this summer and next could see record temperatures on land and in the sea.
Mariana Paoli of relief agency Christian Aid said: “Poor people are already being pushed to the brink through droughts, floods and storms caused by the burning of fossil fuels and now they will be facing the supercharged temperatures of the El Nino effect.
“These people are the worst affected by climate change but have done the least to cause it.”
Australia has not declared El Nino
But while scientists at the US National Oceanic and Atmospheric Administration (NOAA) declared El Nino on Thursday, their Aussie counterparts — who use a stricter definition — still haven’t pulled the trigger.
The BOM has yet to declare an El Nino season, but it may do so in the coming months.
As such, Australia is still officially on “El Nino Alert”, which is one step away from a full declaration.
Earlier this week the BOM said there was now a 70 per cent chance of El Nino forming according to its methodology.
“While the models show it’s very likely the tropical Pacific Ocean temperatures will reach El Nino levels during winter, we have seen some movement in the atmosphere towards El Nino conditions,” BOM Senior Climatologist Catherine Ganter said.
NOAA and the BOM are the two global meteorology agencies that most look to for El Nino and La Nina declarations.
NOAA calls El Nino when sea surface temperatures at Nino 3.4 are 0.5C warmer than normal with conditions expected to last for another five months at least.
The BOM needs it to be hotter — as much as 0.8C.
— With Benedict Brook and AFP.