The writer is a science commentatorThe deep sea is in danger of turning into an invisible wild west. On Sunday, a UN deadline for finalising regulations over deep-sea mining in international waters expired without agreement.

The resulting limbo now gives countries the green light to apply for mining licences — and could spark an ill-advised rush to the ocean floor in search of minerals linked to the green energy transition. The bid to plunder one of the least explored territories on the planet should be reconsidered, given the potentially irreversible impact on marine habitats. Stripping the seabed also risks disturbing stores of carbon locked away for millennia, with unknown consequences for a jittery climate.

The vast, cold, lightless ocean floor, with crushing pressures that can be more than a thousand times those on land, has been quietly eyed for its extractive promise since the 1960s. One draw is the Clarion-Clipperton Zone, an area spanning at least 4.5mn square kilometres in the equatorial Pacific.