Salt is essential for cooking, but too much salt in soil can ruin crops and render fields useless. According to legend, Roman general Scipio Aemilianus Africanus sowed the soils of Carthage with salt after conquering the city during the Punic Wars. And after defeating the Italian town of Palestrina in 1298, Pope Boniface VIII is said to have plowed its lands with salt, “so that nothing, neither man nor beast be called by that name.”

Today it would be very expensive and logistically challenging to gather enough salt to render large swaths of land infertile. But that is precisely what climate change is doing in many parts of the world.

As sea levels rise, low-lying coastal a