Black Summer bushfires may be to blame for Australia’s La Nina weather patterns

A shocking new theory has emerged as a likely explanation for why Australia’s past three summers have been much wetter and cooler than usual, resulting in devastating flooding and loss of life.

While the direct explanation is that it was caused by the very rare occurrence of a triple La Nina weather pattern, there may be a surprising factor behind that.

Scientists have found that smoke pollution from the months-long ‘Black Summer’ bushfires of 2019-2020 may have contributed to the La Nina pattern that hit Australia three years in a row.

In a study published in the journal Science Advances, researchers ran climate models with and without wildfire emissions to determine the role of the fires.

What they found was astonishing. “In fact, we underestimated the effects of the wildfires,” said lead author Dr. John Fasullo of the US-based National Center for Atmospheric Research.

“But what we found in the first two years itself was actually quite interesting — we have a La-Nina kind of reaction,” he told the ABC.

The reason for the research was research into emission reductions during lockdowns due to the Covid-19 pandemic.

But the researchers thought the 2019-2020 wildfires may have had a bigger effect on the climate than the drop in emissions caused by pandemic lockdowns.

The Black Summer fires are believed to have been the first widespread enough to affect climate models, but the findings could provide insight into the link between large wildfires and past climate events.

The Black Summer wildfires, which burned at an abnormally high intensity and size, pumped massive amounts of smoke aerosols into the atmosphere.

Smoke is pictured from a bushfire in East Gippsland, Victoria during the Black Summer 2019-2020

A NASA satellite caught thick smoke (pictured) blanketing southeastern Australia on New Year’s Day 2020

It was so intense that it was comparable to large volcanic eruptions and could be seen from space.

At one point in December 2019, there were over 100 fires burning at once in NSW alone.

Dr. Fasullo said the emissions caused clouds to become brighter, thicker and more durable, which then caused a cooling effect over the southern hemisphere.

This, in turn, likely created favorable conditions for the formation of the 2020 La Nina by helping to move a large tropical cloud belt northward and allowing trade winds to pass beneath it.

RFS volunteers and NSW Fire and Rescue officers are pictured on December 3, 2019 fighting a bushfire encroaching on property near Termeil on the Princes Highway between Bateman’s Bay and Ulladulla

“The trade winds across the equator lead to this steep upwelling of the ocean, and that’s a La Nina event,” Dr Fasullo said.

He added that the wildfires roughly doubled the chances of a long-lasting La Nina.

“They certainly contributed in a material way to both the probability of La Nina and the intensity of La Nina for at least two years.”

The 2020, 2021 and 2022 La Ninas dominated Australia’s weather patterns, causing devastating and record-breaking flooding in the eastern states.