Olive Heffernan takes a deep dive into protecting the world’s oceans in The High Seas

The High Seas

Darragh McManus

The sea is massive. That sounds obvious but, until reading Olive ­Heffernan’s The High Seas, I hadn’t quite grasped the enormity of scale.

Oceans cover 70pc of Earth’s surface and can reach depths of 11 kilometres (Mount Everest is less than nine kilometres tall). And it’s ­positively teeming with life, often of the most incredible kind.