The idea of curbing climate change by seeding the seas with iron gets a knock-back from the biggest investigation so far.
The biggest ever investigation into “ocean fertilisation” as a climate change fix has brought modest results.
The idea is that putting iron filings in the ocean will stimulate growth of algae, which will absorb CO2 from air.
But scientists on the Lohafex project, which put six tonnes of iron into the Southern Ocean, said little extra carbon dioxide was taken up.
Germany’s environment ministry had tried to stop the project, which green campaign groups said was “dangerous”.