The surface, or top 100 metres, of the ocean is now about 35 per cent more acidic than it was at the start of the Industrial Revolution in the late 18th century, with potentially huge implications for Arctic ecosystems.

The changing chemical make-up of the seawater threatens to wipe out large numbers of herring, cod and capelin – a small fish largely used as animal feed – as well as plankton and crabs.

This could affect the livelihoods of indigenous populations that rely on fishing and hunting, for example, the Canadian Inuit, as well as reducing food for birds and larger marine mammals such as walruses.

The acidification could also put further pressure on the rapidly diminishing global…