Australia Officially Declares the Start of El Niño
The Australian Bureau of Meteorology (BOM) has officially declared the start of the El Niño phenomenon, which, according to models, could become the strongest in the modern era, writes ABC News.
Photo: ABC News
El Niño is a prolonged period when the surface water in the central tropical Pacific Ocean becomes warmer than usual. This situation can last up to a year and significantly alters weather worldwide.
For Australia, this is particularly important, as similar events in the past have often led to hotter and drier weather, sometimes even severe droughts.
However, a paradox is currently observed: despite the declared El Niño, Australia has been experiencing a lot of rain recently. This is because El Niño is not a direct weather forecast for a specific region, but merely a record of the state of the ocean and atmosphere in the Pacific Ocean. Australia's weather is also influenced by the Indian and Southern Oceans, as well as local conditions. Currently, these factors are contributing to a wetter period.
At the same time, according to forecasts, as El Niño develops, the second half of the year will likely become drier. This particularly applies to southern and eastern Australia, where rainfall below the average norm is expected between July and September.
Typically, El Niño reduces rainfall in late spring, and its influence may weaken in summer, but this does not always happen uniformly. For example, during the previous El Niño in 2023, its effects were less noticeable during the summer period.
In addition to rainfall, this phenomenon also affects other aspects of the weather. Expected effects include:
- higher daytime temperatures in southern Australia during winter, spring, and summer;
- colder nights in winter and more frequent frosts (although climate change mitigates this effect);
- a shorter snow season;
- a longer and more dangerous fire season due to droughts and extreme heat;
- a delay in monsoon rains in the tropics and fewer tropical cyclones, especially in Queensland.
Meteorologists define El Niño using various indicators in the Pacific Ocean. The main one is the water temperature in the Niño3.4 zone along the equator. It currently exceeds the El Niño threshold (0.8°C), confirming the onset of the phenomenon.
Another important indicator is the Southern Oscillation Index (SOI), which is currently strongly negative (around -23). This indicates a change in pressure in the Pacific Ocean: high pressure predominates near Australia, while low pressure is found near Tahiti.
Additional signs include weakening trade winds, changes in cloud cover, and the presence of very warm water beneath the ocean surface.
According to models, this El Niño could become a record-breaker. The water in the region is already warming at the fastest rate since 1943, and forecasts indicate that temperatures could rise more than 3°C above normal — significantly exceeding the previous record from the early 20th century.
However, the strength of El Niño does not always translate into the scale of consequences in a particular country, so even a record-breaking event does not necessarily mean a record-breaking drought.
It is also noted that this could be the seventh consecutive year that either El Niño or La Niña (the cold counterpart to El Niño) has been observed in the Pacific Ocean, although on average, half of the years are usually neutral. The last time such a prolonged series was observed was from 1969–1976.