Cyclones have been unleashing destruction across the globe — from flattening coastal towns to flooding entire regions.
In Australia, the future looks both familiar and more ferocious: climate models predict fewer tropical cyclones overall, but those that do form will be more intense. There will likely be more category 4 and 5 cyclones, with stronger winds, heavier rainfall, and amplified storm surges due to rising seas.
It’s difficult to pinpoint how much climate change contributes to tropical cyclones, but we know they are intensifying.
Researchers at the Australian National University (ANU), in collaboration with Silicon Valley start-up Aeolus, are investigating a surprising way to stop storms in their tracks – aerosols.
Using computer simulations, they are testing whether the early formation of tropical cyclones can be disrupted by releasing salt-based aerosols into the storm.
“Others have looked at the impact of aerosols on a fully grown cyclone, when it might be about to hit land. We thought it may be easier to stop them before they start,” says lead author of the study, Associate Professor Roslyn Prinsley, an expert in climate disasters. “We’ve now shown it’s possible to reduce their intensity in those early stages”.
Their modelled method involves dispersing microscopic salt aerosols around the edges of a developing cyclone system, potentially using aircraft to distribute the particles into the lower atmosphere.
“Aerosols (small particles in the air) increase the condensation of the vapor in clouds and enhance clouds in the periphery of the cyclone at the expense of the vortex at the centre,” Prinsley explains.
“Imagine a sink and the water whirls down from its plug hole. Now open more small plug holes at the periphery, which will be at the expense of the water going to the central plug hole. So the whirl would weaken.”
The researchers modelled how different aerosol sizes interact with the storm’s structure.
“Our study shows, for the first time, the impacts of aerosols of varied sizes on the formation of a tropical cyclone”, says Prinsley. “We found that coarse aerosols initially dampen vortex acceleration, while fine or ultrafine aerosols boost it first, but later weaken it more than coarse aerosols.”
For now, the work remains in the modelling phase. “Obviously before you go and test on a real cyclone you want to make sure your model is as accurate as possible,” Prinsley explains. “Also, attribution is difficult – we need to show that the intervention itself weakened the cyclone and not natural causes.”
Prinsley believes Australia is well-positioned to lead this emerging field and suggests the waters off Western Australia could be ideal for future trials.
“Cyclones that form in that type of environment, that will never hit land, are the best ones to test our models on,” she says.
“The reality of climate change is that cyclones are going to come further south and further inland, and we will have more intense cyclones. It is critical to do something about them before they hit.” – Associate Professor Roslyn Prinsley.
This research was done in collaboration with Aeolus, a start-up in Silicon Valley that aims to weaken cyclones before they threaten lives and communities.
“This is the only long-term solution,” says Aeolus CEO and co-founder, 20-year-old Koki Mashita.
“In many parts of the world, the intensification of these events due to climate change has already led to significant increases in insurance premiums. As we look into the next few decades, properties will truly become uninsurable, and we will need to intervene,” he says.
This research is published in Geophysical Research: Atmospheres.