‘Like preparing to fight a war’: Can we stop a cyclone in its tracks?

In the 1960s, the US had Project Stormfury to explore the use of cloud seeding with silver iodide to stop hurricanes from forming, an ANU article says, prompting suspicion from Cuban dictator Fidel Castro. The project showed some correlation between seedings and weaker hurricanes, but the project was abandoned.

Prinsley said many international researchers, so far working on models, were keen to work with cyclones in the Australian region because there were no land borders with other countries.

But there were also ethical questions because some marine systems, forests and inland agriculture relied on the rainfall caused by cyclones, she added.

Global research, particularly in the United States, has examined how aerosols can be used to intervene in a mature cyclone. The ANU research is focused on embryonic cyclones, which are basically low-pressure systems with an emerging vortex, to stop them developing further.

The advantage, Prinsley said, was that it required less effort and expense to intervene in an embryonic rather than a mature cyclone. The disadvantage was that it was difficult to tell which embryonic cyclones would become dangerous.

“There’s no point intervening in a cyclone that stays out at sea, and there’s no point in intervening in a cyclone that’s not going to have an impact and do a lot of damage, so that’s actually a huge challenge,” she said.

“Predicting their intensity is really hard and in particular now with climate change, there seems to be more rapid intensification when cyclones suddenly strengthen much faster than expected.”

Prinsley said cyclones were moving further inland and further south, becoming more powerful and carrying more intense rainfall. In the Australian tropics, houses had to be built to withstand category 4 cyclones but could be facing more dangerous storms in future, while houses in Brisbane and northern NSW were not built to withstand cyclones at all, she said.

Cyclones, also known as hurricanes or typhoons depending on the ocean, are low-pressure systems generated in the tropics that obtain energy from warm sea surface temperatures, spin up and then release that energy as they make landfall.

Researchers are also exploring cyclone manipulation by cooling the ocean, given the storms require high sea surface temperatures. In 2009, Bill Gates and climate scientist Ken Caldeira filed a patent to install turbines or other machinery to reduce cyclone intensity by bringing cold water to the surface near hurricane-prone coastlines.

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Norwegian start-up Ocean Therm is working on a concept to use a fleet of ships with giant perforated pipes to release colder water from deeper down the water column near the surface in the form of bubbles. In Ocean Therm’s “dream scenario”, this would reduce a category 3 or 4 hurricane to a relatively weak tropical storm.

​Prinsley said ANU research suggested this method would be more expensive than using aerosols and also slower because it relied on ships rather than aircraft.

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