There is a fishing net somewhere in the North Atlantic tonight that has not had a fisherman for thirty years, and it is still fishing. Until the 1950s a net was hemp or cotton, a line was linen or horsehair, and a hook was tied on with gut. The sea ate all of it. A net lost overboard rotted inside a season, which is why fishermen dried theirs on the quay every night and tarred them every spring, and why the loss of one was a loss and nothing more. The sea took back what it was made of. Then nylon arrived, and polyester, and polypropylene, and the net stopped dying. The UN's estimate is 640,000 tonnes of fishing gear lost or dumped at sea every year. It does not sink and vanish. It drifts, snags on a reef or a wreck, opens, and goes on doing the only thing it was built to do. Fish swim in and die. The dead fish bring the seals and the turtles, which die in it too. The weight of bodies pulls it down, the bodies rot, it rises, and it fishes again. A whale that meets one tows it until it starves. Nobody hauls it. Nobody empties it. Nobody is paid. Nearly half the mass of the great rubbish gyre in the Pacific is not bottles or bags. It is net. We built a fishing net that does not need a fisherman, that cannot be told the season is over, and that will still be killing when the grandchildren of the man who lost it are old. The old net needed a man to work it and died when he stopped. The new one needed a man to make it, once, and never again. Every natural material rots. That was never its weakness. It was the agreement it had with the world, and plastic was the first thing we ever made that broke it.