Australia said it was pushing for a ban of any commercial use of a pioneering technique to reduce the impacts of climate change by “fertilising” the world’s oceans with iron, according to a report by the Sydney Morning Herald.

The practice is proposed as a way to increase carbon dioxide absorption in the ocean and boost fish stocks. It rose to prominence last year when a fishing boat chartered by an American entrepeneur strewed 100 tonnes of iron sulphate into the ocean off western Canada. The iron was meant to increase plankton, boost salmon populations and sequester carbon. Whether the ocean responded as hoped is not clear.

In response, Australia has joined South Korea and Nigeria in trying to ban commercial ocean geo-engineering projects by moving a legally binding amendment to the London Protocol – an international treaty countering dumping-related ocean pollution.

University of Tasmania Associate Professor Peter Strutton said the increased phytoplankton would absorb more carbon dioxide from the atmosphere. When the phytoplankton dies it sinks to the bottom of the ocean taking some carbon dioxide with it.

”It might take more CO2 out of the atmosphere, make the surface ocean more productive – which might help feed more fish – and perhaps store more carbon on the bottom of the ocean in sediments,” Professor Strutton said.

But ocean fertilisation could also have unintended consequences, such as causing damaging toxic algae blooms, increasing ocean acidification, and depleting oxygen in deep waters. So far there have been more than a dozen formal scientific trials, with mixed results.