For many in shipping, zero-carbon fuels feel so far away, not only from a technology standpoint but also because of how long it will take to scale up supply.

But as shipping faces growing calls to take steps to tackle its greenhouse gas footprint now, rather than wait for a silver bullet fuel to emerge, one decarbonisation tool appears to be increasingly floating into the mainstream: bubbles.

Carnival Corp, the world’s largest operator of cruise ships, recently unveiled plans to install air lubrication systems on at least 10 more vessels, on top of four ships already utilising the technology that uses a layer of tiny bubbles to increase fuel efficiency at sea.