Blog icon

20 September 2023 Expert commentary

The Bureau of Meteorology has announced that the El Niño phase of the El Niño-Southern Oscillation (ENSO) is now underway. Up until now, we were in the neutral phase of ENSO since the "triple dip" La Niña over three consecutive years ended earlier this year.

CSIRO researchers explain the significance of El Niño conditions for Australia's primary producers and communities, as well as for ecosystem recovery and disaster preparedness during southeast Australia's bushfire season.

What do we know about the strength of this year’s El Niño event?

Dr Nandini Ramesh, Senior Research Scientist, explains:

"Forecasts show very high confidence that the warm sea surface temperatures over the eastern-central tropical Pacific of this El Niño event will persist through the summer months.

"The atmosphere has begun to show the expected response to these warm sea surface temperatures, with a weakening of the surface winds in the western Pacific and suppression of convection over Indonesia. The climate around the world is also being influenced by the record warm temperatures over other ocean basins.

"The odds of a strong El Niño event are now 2 in 3. Note that the 'strength' or 'magnitude' of an event is measured and forecasted in terms of the sea surface temperatures in the eastern-central equatorial Pacific, and not in terms of its impact.

"In Australia, the relationship between event magnitude and impact is not linear: some of the worst bushfire years have been during relatively weak El Niño events.

"The Bureau of Meteorology's forecasts indicate that the Indian Ocean Dipole will likely be positive this spring, which usually promotes drier conditions over eastern and southern Australia, and forecasts also indicate a warmer than normal spring for most of the continent.”

What do we know about the flavour of this particular El Niño?

Dr Chris Chapman, Ocean Dynamics Team Leader, explains:

"At present, we appear to be experiencing an "eastern Pacific" or "classical" El Niño. This is where the highest ocean temperatures are concentrated in the eastern Pacific ocean between the dateline and South America.

"Notably, the warmest sub-surface temperatures are now concentrated in the east as well, which was not the case a few months ago. El Niño conditions are typically associated with higher than average temperatures in the Coral Sea and Great Barrier Reef regions.

"While it remains to be seen whether these temperatures reach or breach records, the Great Barrier Reef is currently experiencing temperatures around 1 °C warmer than normal for this time of year."

How can communities prepare for an anticipated hot and dry summer?

Dr Mahsan Sadeghi, Architectural Scientist, says:

“El Niño is a natural climate phenomenon that can have a big impact on our environment – including our homes. Incorporating sustainable design, improving insulation, and using energy-efficient cooling methods like natural ventilation and shading can help our homes stay safe and comfortable during El Niño-induced weather events such as heatwaves.

"Environmentally friendly building materials like sustainable concrete and bamboo can protect our living environments and support broader climate resilience efforts. Sustainable technologies such as wind towers for natural ventilation, geothermal heating and cooling, solar panels, play an important role here too."

Is climate change making El Niño events worse?

Dr Jaci Brown, Climate Intelligence Director, explains:

“Our atmosphere is warmer due to climate change and so hot, dry conditions that are associated with El Niño are exacerbated. Whether El Niños are changed or made worse by climate change is a more complex question.”

Will an El Niño event make it more likely that the world will overshoot our goal under the Paris Agreement to limit warming to 1.5 degrees?

Dr Jaci Brown, Climate Intelligence Director, explains:

"El Niño years are generally warmer than other years over Australia and the whole globe on average. Australia is already 1.47 °C warmer as a long-term trend. We will see individual years go higher and lower than this. Globally the warming increase is around 1.1 °C and it is less clear how much higher this El Niño would warm the whole Earth – but it would only be for the period of the El Niño which would ease off in Autumn of 2024."

Dr Nandini Ramesh, Senior Research Scientist, adds:

"Yes, it will make this more likely, at least temporarily. El Niño events involve the release of a large amount of heat from the ocean's surface to the atmosphere, and the global average temperature record usually shows a short-term “bump” in temperatures during El Niño years as a result. Whether we cross 1.5 degrees in a more permanent way remains to be seen."

Could we get three El Niños in a row?

Dr Jaci Brown, Climate Intelligence Director, explains:

“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 Niño. At this stage our climate models cannot give us reliable forecast information beyond about 6 months. But we have seen multi-year droughts before and we will see them again.”

Dr Nandini Ramesh, Senior Research Scientist, adds:

"This is something we have not seen before; the longest El Niños have been about two years long. La Niña and El Niño are not perfect mirror images of each other, and La Niña events often last longer than El Niño events do."

Are parts of Australia more susceptible to drought during El Niño events?

Dr Graham Bonnett, Lead, Drought Resilience Mission, explains:

"An El Nino points to possible drier conditions and an increased risk of drought. Droughts occur after an extended period, such as more than a year, of much lower-than-average rainfall.

"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.

"While a drought can technically happen anywhere, its often the regional communities that rely heavily on agriculture who are most affected.

"Australia's south is expected to experience less rain in future in general. This long-term drying trend may increase the region’s susceptibility to impacts of lower rainfall years in future.”

Dr Carly Tozer, Senior Research Scientist, adds:

"El Niño is a good indicator of dry conditions in eastern Australia as a whole, but it doesn’t necessarily translate to dry conditions ahead. At individual locations, like the eastern seaboard, it does little to shift the normal odds of dry conditions."

"For parts of northern and southeastern Australia, including the Murray Darling Basin, El Niño significantly increases the odds of a dry spring season. But in large parts of WA, Western Tasmania and the eastern seaboard, it does not markedly change odds of dry conditions.

"It's important to consider your specific location in Australia, when interpreting what an El Niño forecast means for you.

"While El Niño plays a large role in moderating Australia's climate, it's not the only driver of dry conditions in Australia. Other processes like the Indian Ocean Dipole, Southern Annular Mode and related or unrelated weather systems all contribute to Australia’s climate variability."

What can Australia’s primary producers do to prepare for possible drier conditions?

Dr Graham Bonnett, Lead, Drought Resilience Mission, explains:

"Livestock producers can monitor pasture growth and make stocking adjustments to match feed availability as the year unfolds.

"It's also important to monitor the amount of soil moisture relative to crop development. If it turns out to be a low rainfall year, crops can be conserved as hay or silage rather than going through to grain."

Will ecosystems like those in the Murray-Darling Basin have a chance to recover from flooding events earlier this year?

Dr Francis Chiew, hydrologist and Group Leader explains:

"It's too early to predict how a potential El Niño event may impact flows in the Murray-Darling Basin. The good news is wet conditions from three successive years La Niña years have filled our reservoirs and provided what is essentially a buffer for the system.

In terms of the bigger picture, we can certainly expect droughts to become more frequent and more severe in the decades ahead, which will paint a more complex picture for recovery.

We've always managed our water ecosystems around the swings of flood risk and planning for droughts. However, climate change means that we also have to manage a drying trend – meaning that droughts are expected to become more frequent and severe."

Should we be worried about an increased fuel load in the lead up to southeast Australia’s bushfire season and an El Niño event?

Dr Andrew Sullivan, Leader, Bushfire Behaviour and Risks, explains:

"An El Niño event does not necessarily mean that a bushfire season will a big one. However, the last few years have seen exceptional growing conditions for vegetation in most agricultural and bushland areas, particularly in south-eastern Australia. At the same time, wetter conditions have also made it more difficult for authorities to implement their planned hazard reduction burns in many locations. Bushfires still require elevated fire weather and ignition sources for increased vegetation growth to shift to a potential for increased available fuel and the potential for widespread bushfires.

"If we face consecutive El Niño events and extended periods of decreased rainfall, then increased vegetation growth from recent years could become available bushfire fuel. Areas of open vegetation, such as agricultural lands, grasslands and woodlands follow an annual burning cycle. The threat of bushfires will transition from these areas to forests, where multiple years of drying vegetation heighten the potential for increased fuel and potential for large intense fires if ignitions coincide with extreme fire weather events."

Chief Research Scientist, Dr Pep Canadell adds:

"Depending on where drought hits the most during this El Niño, we could have a big fire season in the grass-dominated rangelands in large parts of the continent and savannahs of the north, where the build-up of grass biomass over the past three wet years can quickly dry and become flammable to fire.

"In the eastern and southern parts of the country, open woodlands could be equally exposed to high fire risk, but we expect forests to continue to be wetter than average from La Niña years, making it less likely that fuels will be primed for a big forest fire season."

Can we expect more dangerous bushfire weather as a result of climate change and El Niño?

Chief Research Scientist, Dr Pep Canadell explains:

"Weather conditions conducive to bushfire in Australia have already increased over the past two decades, particularly in the southern and eastern parts of the country. This trend is consistent with the observed increased in forest burned area and megafire seasons. Projections for the next decades under all future climate scenarios show that fire weather will continue to increase. The length of the bushfire season increases when weather conditions are conducive, and fuels and an ignition source are available."

Can El Niño years exacerbate greenhouse gas emissions?

Chief Research Scientist, Pep Canadell explains:

"Yes. While the Australian landscape tends to be a large carbon sink during La Niña years, it reverses to become a carbon source during El Niño years. This is because the amount of carbon dioxide sequestered by vegetation is closely related to the amount of water that is available. A strong El Niño event could therefore limit the ability of vegetation to sequester carbon dioxide from the atmosphere.

"An increase in drought conditions can lead to fires, which would further exacerbate emissions."

What has changed in terms of forecast and safety technology since the 2019/20 bushfires?

Principal Research Scientist, Dr Fabienne Reisen explains:

"We have extended the smoke forecasting capability Air Quality Forecasting System (AQFx) to be available to all states and territories in Australia. The AQFx forecasts and relevant smoke observation data are displayed in a cloud-based visualisation application called the Air Quality Visualisation system (AQVx). It provides a tool for managing population exposure to smoke.

"We have also assessed the performance of AQFx for the 2019/20 bushfires. This has driven the development of improvements to increase the accuracy of the AQFx forecasts. We have also started deploying low-cost particle sensors called SMOG units to WA, SA, and NT to cover sparsely monitored areas."

Principal Research Scientist, Dr Andrew Sullivan adds:

"Rural fire authorities and land management agencies across the country have continued to improve their ability to plan for and respond to wildfires. A new Australian Fire Danger Rating System, largely built on CSIRO's bushfire behaviour science, was introduced prior to the 2022/23 fire season. It continues to be refined to help communities understand their daily bushfire danger.

"A new next-generation wildfire spread simulation tool called Spark Operational was also rolled out nation-wide recently. This tool, developed by CSIRO in conjunction with the Australian National Council for Fire and Emergency Services, will help rural fire authorities predict the likely behaviour and spread of bushfires across the landscape so they can better plan and implement suppression actions as well as issue timely warnings to communities."

Do El Niño events have an economic impact?

Yi Liu, postgraduate student says:

"Our research shows that El Niño events impact the global economy to tune of $600 USD. The 2015/16 strong El Niño event resulted in a global loss of around 68 billion US dollars. Weaker El Niño events, like 2018/19 still incurred a substantial loss of around $6.2 and $9.0 billion US dollars."


An earlier version of this article was published on 6 June 2023, and was subsequently updated on 4 July 2023.

Contact us

Find out how we can help you and your business. Get in touch using the form below and our experts will get in contact soon!

CSIRO will handle your personal information in accordance with the Privacy Act 1988 (Cth) and our Privacy Policy.

First name must be filled in

Surname must be filled in

I am representing *

Please choose an option

Please provide a subject for the enquriy

0 / 100

We'll need to know what you want to contact us about so we can give you an answer

0 / 1900

You shouldn't be able to see this field. Please try again and leave the field blank.