Should our planet be ravaged by nuclear war, those who survive may not starve to death, or so suggests a new study. Yes, the million tons of radioactive dust and smoke and soot that result from the fires caused by the bombs will be sent into Earth's atmosphere, sharply curtailing sunlight and causing surface temperatures to plummet. As expected, "This could decimate agriculture as it is practiced today," write researchers in Earth's Future. Realizing "resilient food sources" would be necessary in the event of such a nuclear winter, they zero in on one viable one: seaweed, specifically Gracilaria tikvahiae, which USA Today reports is known as red seaweed.
Their modeling showed that even after nuclear war, seaweed can be grown in tropical oceans. In fact, "The growth of seaweed actually increases after a nuclear war, because more nutrients become available in the ocean," they write: Colder air would cause surface water to sink further, which would help circulate more nutrient-rich water to the surface. Per their simulations, within nine to 14 months seaweed could meet 45% of the global human food demand, which LiveScience details as replacing 15% of the food we eat, 50% of current biofuel production, and 10% of animal feed.
If you're wondering why all of it wouldn't go to feed humans, LiveScience explains the iodine in seaweed can be toxic if too much is consumed, making "indirect" uses, like feeding animals, valuable. The researchers write, "While a pure seaweed diet is not possible, this intervention could have an expected value of averting up to ~1.2 billion deaths from starvation (15% of human food demand times 8 billion people)." The main challenge, the study notes, would lie in humanity's ability to construct new seaweed farms quickly enough. (More discoveries stories.)