The sudden warming of Britain’s seas will tear through ocean life like a wildfire | Philip Hoare

What happens when the chill of our seas turns to a soupy stew? Fragile ecosystems will be destroyed and food sources for wildlife will disappear

Last weekend, at the very easternmost edge of England, tens of thousands of people of all ages gathered at a beach festival in Lowestoft to celebrate the sea joyously. To dance to trance music and listen to Linton Kwesi Johnson recite his poetry, and to hear marine scientists explain to seven-year-olds exactly why the sea smells the way it does. It was an idyllic scene. From dusk to dawn and back again, everyone was drawn to the vast and glorious element that connects us to the rest of the world.

But then, amid the revelry, a solemn procession appeared. Two dozen festivalgoers carried a series of blown-up photographs into the sea. They were portraits by the artist Gideon Mendel of people, many of them from the global south, standing amid the floods that had overturned their lives. Suddenly, in the face of their fates, the sea seemed not so benign after all. It was a reminder that sea levels are rising around the world; and that here in the UK we face our own potential disaster - the drastic sudden warming of the sea off Britain and Ireland.