Australia Set For Dry El Niño

Kevin Tolhurst AM

An El Niño event has arrived, according to the World Meteorological Organisation, raising fears of record high global temperatures, extreme weather and, in Australia, a severe fire season. The El Niño is a reminder that bushfires are part of Australian life – especially as human-caused global warming worsens. But there are a few important considerations to note.

First, not all El Niño years result in bad bushfires. The presence of an El Niño is only one factor that determines the prevalence of bushfires. Other factors, such as the presence of drought, also come into play. And second, whether or not this fire season is a bad one, Australia must find a more sustainable and effective way to manage bushfires. The El Niño threat only makes the task more urgent. An El Niño is declared when the sea surface temperature in large parts of the tropical Pacific Ocean warms significantly.

The statement by the World Meteorological Organisation, released recently, said El Niño conditions have developed in the tropical Pacific for the first time in seven years “setting the stage for a likely surge in global temperatures and disruptive weather and climate patterns”. The organisation says there’s a 90 per cent probability of the El Niño event continuing during the second half of 2023. It said El Niño can trigger extreme heat and also cause severe droughts over Australia and other parts of the world.

There is every reason to expect fire activity will increase with human-induced climate change as well. Humans have also changed the Australian fire landscape – both First Nations people and, for the past 200 years. Changes brought about by Indigenous Australians were widespread, but sustainable. Their methods included, for example, lighting “cool” fires in small, targeted patches early in the dry season. 

Changes brought about by European colonisers have also been widespread – such as land clearing using fire, and fire suppression to protect human life and property. Australia has just experienced a period of high rainfall across the continent due to a La Niña event combined with two other climate drivers: a negative Indian Ocean Dipole and a positive Southern Annular Mode. It means the soil is moist and plants are flourishing.

Now, we’re set to enter into a drying period driven by an El Niño. The abundant plant growth leading into a dry period is likely to result in widespread bushfires across Australia. In Australia, El Niño events are associated with hotter and drier conditions, leading to more days of high fire danger. But large and severe forest fires also need a prolonged drought to dry out fuels, especially in sheltered gullies and slopes. Soils and woody vegetation are currently moist following the La Niña period.

The evidence bears this out. Take, for example, analysis of fire dynamics in two areas north and south of the US-Mexico border. Between 1920 and 1972, authorities on the US side had spent hundreds of millions of dollars on firefighting aircraft and other resources trying to suppress wildfires. 

Damaging bushfires will return to Australia in the near future. The expected return of another El Niño should heighten efforts to create a more considered and sustainable fire management regime – particularly in southern Australia.

Experts, including me, have devised plans to guide the shift. They include: effectively managing the land with fire, including promoting Indigenous Australians’ use of fire engaging communities in bushfire mitigation and management, better coordination across land, fire and emergency management agencies and ensuring fire management is based on “best practice” approaches.

- The Conversation