The Bureau of Meteorology firmed up its guidance for this year for the weather pattern known to produce wet and windy summers in Australia, saying it was now underway, after earlier predicting a strong chance.
The incident puts the country’s east coast on alert when many residents are still rebuilding after the latest La Niña-related flooding in early 2022.
The weather phenomenon was “among the factors expected to push Australia’s climate into a wetter phase and … has shaped our forecast for the coming months which show more than an 80% chance of above-average rainfall for many parts of central east Australia”. the office said in a statement.
Australia’s wild weather brought the worst wildfires in a generation in late 2019 and early 2020, followed by two La Niña patterns that swelled rivers beyond their banks and left thousands of homes uninhabitable.
“This is not good news for communities, businesses, homeowners and renters who live or operate from buildings and homes that are at risk of flooding,” said Mark Gibbs, adjunct professor at the Institute for Future Environments at the Queensland University of Technology.
“This can be particularly problematic for those still recovering from the recent floods, especially given the current challenges of securing services from builders and suppliers,” he added.
With La Niña, sea surface temperatures in the eastern Pacific are cooler than normal, and waters in the tropical western Pacific are warmer than normal, creating moisture that brings rain to eastern and central Australia.
La Niña and climate change
Although La Niña — the opposite of El Niño — events are a regular feature of global weather patterns, rising global temperatures may moderate or reverse their effects. La Niña tends to lower global temperatures, but in recent years the planet has warmed so quickly it’s like hitting a speed bump at 80 mph; it hardly registers.
It is likely that it is too early to know how climate change will affect these models; studies are beginning to show how climate warming can increase the effects of El Niño and La Niña. Climate change may increase the severity of weather events resulting from El Niño and La Niña patterns, according to a 2018 study of atmospheric conditions that simulated climate conditions.
The top spots on the list of warmest years used to be reserved for strong El Niño years, but human influence has long overwhelmed the planet’s natural temperature regulators. For example, La Niña was present in parts of 2020, but the year was still tied with 2016 (an El Niño year) as the planet’s warmest.