Industrial meat production is killing our seas. It's time to change our diets

America's addiction to cheap meat, fed on corn and soy in vast indoor factories, comes at a high cost to our own health and that of the planet

• Callum Roberts is professor of marine conservation, at the University of York, UK

Every spring, as the snows thaw, water rushes down the Mississippi and Missouri rivers, spreading life, then death into the Gulf of Mexico. The floodwaters are laden with fertilisers washed from fields and factory farms. As spring turns to summer, excessive nutrients first drive a huge bloom of living plankton, then cause death on a gargantuan scale as a dead zone blossoms across the seabed. Most years it grows swiftly to over 5,000 square miles of seabed, killing everything that cannot outrun it.

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