El Nino is a naturally occurring weather phenomenon that causes variations in temperature and winds across the Pacific Ocean and influences weather patterns globally. While the world has experienced many strong El Nino events in the past, none has been as exceptionally strong or developed as quickly as the current event.
Scientists track El Nino activity using temperature data from the tropical Pacific Ocean near the equator. Historically, this involved measuring how high or low temperatures were across the region. Scientists and weather organisations, including Australia’s Bureau of Meteorology, now use a relative index that accounts for background warming caused by climate change. This makes it easier to determine the intensity of El Nino in a warming climate.
The current El Nino stands out for two main reasons: it has developed unusually early and has reached exceptionally high temperatures.
El Nino typically peaks between November and January, but the current event is already unusually warm this early in the season and has yet to reach its summer peak.
Recent data shows that the relative index for August was 2.3 degrees Celsius above average, making it stronger than other El Nino years. In Australia, El Nino years tend to coincide with hotter and drier conditions. However, every El Nino is different and can produce different impacts. The current El Nino is expected to lead to record-breaking global temperatures in 2027.
The historic El Nino is already altering weather patterns around the world, with the most direct and severe effects being felt in countries surrounding the Pacific Ocean.
Indonesia, for example, was battling massive wildfires this month. Scientists understand the current El Nino to be a major driver of the increasingly fierce blazes.
El Nino is also reshaping how and where cyclones form. Satellite pictures currently show four active tropical cyclones in the Pacific, stretching from near Japan to as far away as Hawaii. This is extremely unusual. El Nino typically increases cyclone activity in the eastern and central Pacific by carrying warmer water into those regions. Usually, only one or two such cyclones are seen.
Australia is more removed from the direct effects of El Nino, but its influence is expected to become stronger as the country heads into spring.
The Bureau of Meteorology’s seasonal forecast suggests Australia has so far experienced a textbook response to El Nino. Temperatures are rising to as high as 37 degrees Celsius this week in parts of northern Australia, while conditions are becoming drier.
Much of eastern and central Australia can expect an unusually dry spring and summer, potentially increasing bushfire risk. However, a record-breaking El Nino will not necessarily trigger catastrophic bushfires across Australia.
Three previous strong El Nino events illustrate the differing effects. In 1982, a robust El Nino coincided with drought-like conditions. By contrast, during the El Nino years of 1997-98 and 2015-16, some parts of Australia received drenching rain while other regions barely recorded any moisture.
As the El Nino intensifies, it is likely to exacerbate the consequences of climate change. Countries around the world will face increasingly extreme weather as the phenomenon strengthens.
The most disadvantaged communities are expected to be hit hardest, with nearly 50 million people in vulnerable communities likely to be pushed into acute hunger. Farmers across the globe face increasingly unpredictable weather, ranging from crop-destroying floods in South America to severe drought in parts of Africa.
Governments must invest in robust research to protect people and ecosystems. More modelling capability is urgently needed to identify which regions will be worst affected by the strengthening El Nino. This is particularly important for Australia, where there is a lack of understanding of how climate change combined with a strong El Nino will affect local conditions.
The record-shattering El Nino is already compounding the destructive effects of climate change, placing greater pressure on governments to understand its consequences and protect vulnerable populations and ecosystems.
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