If society ever collapses because of nuclear war, survivors can live off of the resilient seaweed that gets left behind, a new study says.

The study, published earlier this month by Earth's Future, found that seaweed will likely survive nuclear winter and could make a good food source "due to its ability to grow quickly in a range of conditions."

"A global simulation shows that seaweed could provide a significant contribution to global food security in nine to 14 months," the study concluded.

Researchers used Gracilaria tikvahiae, commonly known as red seaweed, to create the model and simulate its growth in conditions similar to what the world would experience in a nuclear winter. They based the model on available nuclear winter climate data and simulated the first 10 years after nuclear war to calculate the seaweed's growth rate for all the world's oceans.

Scientists believe the seaweed would survive more than just nuclear war. The study states that it would stay resilient during many cataclysmic events that cause an abrupt loss or reduction of sunlight.

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Examples of abrupt sunlight reduction scenarios

• Nuclear war
• An asteroid or comet impact
• The eruption of a large volcano that spews out large amounts of particles into the atmosphere

Any of these event could "decimate agriculture as it is practiced today," according to the study.

How would nuclear winter affect life as we know it?

According to researchers, the above scenarios could inject massive particles into the upper atmosphere. The particles would then limit the amount of sunlight that reaches Earth's surface.

Not only would it disrupt the planet's global climate, but in a nuclear winter, the temperature could drop up to 48 degrees Fahrenheit.

"In the historical and paleo records, large volcanic eruptions lead to reductions of global average temperature on the order of (33.8 degrees Fahrenheit), with higher reductions on land and in the Northern Hemisphere, associated with famines, disease outbreaks, political instability and regime changes," the study says.

Should the U.S. and Russia experience an "all-out war," for example, reduced sunlight, temperature, and precipitation could decrease global agriculture by 90% in the worst year if precautions are not taken, according to the study. But there are some caveats to that figure.

"The ultimate effects of the nuclear war on the food system strongly depend on global trade continuing and the scale of the war," the study says. "There will also be strong differences regionally, with some regions still being able to produce food even in extreme scenarios," such as Australia.

Why is seaweed a good candidate for the apocalypse?

Because it doesn't require a lot of tech to grow and it grows quickly.

According to researchers, the world is largely unprepared for a sunlight reduction scenario. Currently, wheat is the most widely stored food, but the global storage would only last a few months, and an alternative would be needed.

"These alternative foods need to reliably produce food over several years, even if there is less sunlight available, and the temperature is lower," the study says.

Such alternatives could include things like greenhouse crop production and synthetic fat from petroleum, and a number of others but they're in the early stages of development.

Seaweed is not only a resilient food that can be produced in "low-tech" settings, it grows fast and in a variety of climates and conditions, according to the study.

Seaweed as part of the global food supply

In just nine to 14 months, the seaweed from the study could significantly contribute to global food security and provide 45% of the world's food, the study says.

The study says that the Food and Agriculture Organization of the United Nations has been highlighting seaweed as a valuable addition to the global food supply for decades.

Three factors are fueling an interest in "seaweed utilization," according to the organization.

1. It's nutritious and contains minerals like iron, calcium, iodine, potassium and selenium. It's also rich in vitamins A, C and B-12.
2. It's sustainable and doesn't require fertilizers, land degradation or deforestation.
3. It's versatile and can be used in pharmaceuticals, cosmetics, food and animal feed.

How would nuclear winter affect seaweed growth?

The study says that there are two clear findings from their study of seaweed.

1. Growth rate is directly related to nuclear war severity. It grew faster under more extreme conditions.
2. The growth of seaweed is fastest at the beginning of a 10-year period. Its growth peaks after the second year and slows down over time.

The results seem "counterintuitive, as one would expect that seaweed growth would be more limited the more climate is impacted," says the study.

However, it states that this phenomenon occurs because the main factor that affects seaweed's growth is lack of nutrients, not temperature or light.

"The ocean surface is generally nutrient-poor," states the study. But, nuclear war changes that as global ocean circulation patterns are disrupted and nutrients are brought to the surface.

The study's findings

In conclusion, the study found that seaweed's prolific growth could avert global famine and prevent the catastrophic effects a famine would bring.

"Investing in the construction of seaweed farms could prevent global famine in abrupt sunlight reduction scenarios, potentially averting a significant number of deaths from starvation," David Denkenberger, associate professor of mechanical engineering at the University of Canterbury, told Phys.org.