Prelude

First, they were bright white dots moving in the distance between sea and sky. Then, as I reached the end of the land at the cliff’s edge, the gannets were everywhere. From eyeline to the waterline almost two hundred metres below, huge birds filled all the available space. They followed invisible contours through the air in every direction and on every horizontal plane. Somehow, silently, they knew to steer to avoid each other, their black-tipped wings never touching. Those not in flight were sitting on every piece of cliff with room to land. They were lined up on ledges, one bird deep, and the flatter patches of scree were studded in nests, always spaced a sharp beak’s biting distance apart.

If someone told me this was all the gannets there are, every last one of them, coming to nest on these very cliffs, I might easily have believed it. But other colonies exist on both sides of the Atlantic, some even bigger than this one, and all of them in places where the surrounding ocean contains enough prolific life and food to sustain so many parents and hungry chicks. Gannets dive from great heights to hunt beneath the surface, folding their wings back and piercing the water with their arrowlike heads. Air sacs under their skin, like a subdermal cloak of bubble wrap, protect their bodies from the impact of thirty-metre dives. The ammoniacal tang of guano that wafted from the colony told me about the ocean’s immense productivity and all the fish they’ve been catching.

I came to the gannetry at Hermaness, the northernmost headland on the northernmost inhabited island in Scotland, because I wanted to see an outrageous amount of healthy ocean life. Gannets are the North Atlantic’s biggest seabirds, with metre-long bodies and close to a two-metre wingspan. They don’t have the vivid blue or red webbed feet of their tropical cousins the boobies, but they have their own understated elegance. Mostly white, the adults have a dusting of peachy-yellow feathers on their neck and head, a long, tapering beak, and striking pale-blue eyes ringed in cobalt—a gleaming swipe of eyeshadow, like Marilyn Monroe in an Andy Warhol print. I had only ever seen an occasional, solitary gannet, usually from afar, and had long wondered what it would be like to see more. When I found out that they gather in enormous colonies in the Shetland Islands, I decided to see for myself tens of thousands of these huge seabirds at once. I wanted to stare and soak up the awe of it all and remind myself that places like this still exist.

That day, July 18, 2022, when gannets lured me to the farthest end of the British Isles, became the day when my outlook on the world changed. It marked the beginning of the United Kingdom’s first “red” extreme heat warning. Two days of national emergency had been declared because of a heatwave so severe it put human lives at risk, and people were told their daily routines would have to change. Advice for the worst-hit areas, including my hometown of Cambridge, was to stay indoors, shut and cover windows, and generally slow down. During the hottest day in the United Kingdom on record, runways and roads melted. Train services were suspended. People lay awake throughout the warmest night ever, when temperatures didn’t fall below twenty-five degrees Celsius. And Britain wasn’t alone. Extreme heat was engulfing western Europe. Portugal was suffering from a worsening drought, and parts of France and Spain were ablaze with wildfires.

Meanwhile, at Hermaness, a thousand miles north of my home, it was mild and pleasant, but it was strange and unsettling to know that everywhere to the south was far hotter. Missing that heatwave, I think, made it even more disturbing as I tried to imagine what was goin