Myth: We can cool the planet by seeding the oceans with iron dust

We can cool the planet by seeding the oceans with iron dust, to generate phytoplankton blooms. These would absorb the CO₂ we are currently emitting.

Fact:

This idea, known as ‘ocean iron fertilisation’, works in principle, in that phytoplankton do require iron in order to grow, and seeding the oceans does produce phytoplankton blooms. Unfortunately, studies have shown that most of the CO₂ absorbed by the blooms is released back into the atmosphere when the phytoplankton die, rather than sinking to the bottom of the ocean, as proponents of the idea had hoped. This means ‘ocean iron fertilisation’ is not a viable solution to the problem of global warming. Not surprisingly, its advocates have gone quiet of late.