This year’s El Niño is expected to be strong to very strong, tilting the odds toward a hotter, drier winter and spring across southern and eastern Australia. Droughts, water shortages and a dangerous fire season become more likely.

It makes sense to prepare. But the size of the event isn’t set in stone.

For authorities, farmers and land managers, this poses a challenge – wait, and risk being unprepared, or act with a chance preparations may go to waste. Prescribed burn windows, water allocation deadlines and decisions about crop sowing all need to happen before the forecast solidifies.

Faced with decision problems like this, it’s best to stage interventions, starting with low-cost, low-regret actions and preparing contingency plans in case the worst happens.

Why are authorities worried?

Forecasters expect El Niño to keep strengthening into spring.

But a strong event doesn’t always mean worse conditions here. The very strong 1997–98 El Niño resulted in near-average rainfall in most of Australia, while the far weaker 2002–03 event helped produce the severe Millennium Drought.

The Indian Ocean Dipole (IOD) climate driver can either intensify or weaken El Niño’s effect on Australia.

It’s not yet clear which way it will go, though models suggest it may switch from neutral to positive into spring. If it does, the chances of dangerous levels of drying increase substantially.

Over 2018 and 2019, these two climate drivers overlapped, causing intense drying ahead of the Black Summer bushfires. In 2023, they overlapped again, producing Australia’s driest three-month stretch on record.

We should know if they will overlap this year by late July or August.

From reacting to acting

It makes sense to lay out stages of action and do more as necessary, rather than waiting for certainty.

State government drought responses are largely structured like this.

But federal leaders have consistently relied on ad-hoc spending as droughts worsen........

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