When the cod disappeared from the Grand Banks of his Newfoundland home, fisherman Bren Smith saw the light. He realised that we need a new relationship with the oceans- the age of the hunter-gatherers was over and the time of the ocean farmers had begun. After many years of trial and error he developed a new farming system that produces thousands of tonnes of shellfish and edible seaweed, cleans the oceans and absorbs our carbon emissions.

Tom Heap meets Bren and takes a trip to the seaweed farm of the Scottish Association for Marine Science to see if the new techniques in ocean farming can be replicated around the islands and sea lochs of the west coast of Scotland.

Dr Tamsin Edwards of King's College, London, joins Tom to calculate just how much of our carbon emissions might be swallowed by farming the oceans.

Producer: Alasdair Cross

Researcher: Sarah Goodman

Produced in conjunction with the Royal Geographical Society. Particular thanks for this episode to Professor Jennifer Smith of the University of California San Diego and Professor Michael Graham of San José State University.