Sea otters could lock nearly 10million tons of carbon from the Earth’s oceans, if their population was resorted to healthy, pre-hunting levels, according to an American scientist.

Chris Wilmers, at the University of California, Santa Cruz, and colleagues determined that the endangered animal, feasting on sea urchins, helped the growth of kelp forests, which can sequester at least 0.18 kg of carbon from the atmosphere for every square metre of otter occupied coastal waters.

In former kelp forests that have lost their otters, Wilmers says, “All you are left with is piles of urchins and very little else”, reports the New Scientist.

Wilmers presented the findings at the annual meeting of the Society for Conservation Biology in Edmonton, Canada, this month.