Published: Nov. 9, 2020 By
Mushroom cloud expands over ocean

The Castle Bravo nuclear weapons test off Bikini Atoll in 1954. (Credit: U.S. Department of Energy)

A new study reveals the damage that a nuclear war , from salmon to tuna and even shellfish.

The aftermath of such a conflict could put a major strain on global food security, an international team of scientists reports. The group estimates that a nuclear war might cut the amount of seafood that fishing boats are capable of bringing in worldwide by as much as 30%. 听

In short span of time, in other words, those impacts could rival the toll that climate change is taking on fisheries across the globe, said study coauthor Nicole Lovenduski.听

鈥淚t鈥檚 similar to what鈥檚 going to happen by the end of the century, and that鈥檚 already concerning,鈥 said Lovenduski, an associate professor in the Department of Atmospheric and Oceanic Sciences at the University of Colorado Boulder. 鈥淭o have something of the same magnitude happen over such a short period of time is really remarkable.鈥

The researchers published their findings today in the Proceedings of the National Academy of Sciences. The effort is part of a multi-year project led by 抖阴旅行射 Boulder Professor Brian Toon and Alan Robock of Rutgers University to examine the global costs of a potential nuclear war. The team鈥檚 latest findings, however, come with a rare silver lining, said Kim Scherrer, one of two lead authors of the new study.

A man pulls up a cod pot from the Atlantic OceanA shrimp boat sails off the coast of Oregon

Top: A man pulls up a cod pot from the Atlantic Ocean; bottom: A shrimp trawler off the coast of Oregon. (Credits: via ; via )

With a bit of planning and proper management today, humans could help to keep fisheries productive, even in the event of a nuclear war鈥攑otentially allowing these vital sources of food to make up for the loss of crops on land. For Scherrer, a graduate student at the Institute of Environmental Science and Technology of the Universitat Aut貌noma de Barcelona, the results are a wake-up call.听

鈥淭his is the extreme example of how our technology has made us capable of influencing the oceans, and how that could lash back at us,鈥 she said.听

Darkening skies

The team鈥檚 findings come not long after that 鈥渢he world continues to live in the shadow of nuclear catastrophe.鈥澨

In this case, that shadow can be a literal one. 听

Previous research from Toon and Robock鈥檚 team has revealed that even a relatively minor nuclear conflagration could loft humungous amounts of black soot high into Earth鈥檚 atmosphere. There, the debris would cause the globe to grow darker and colder. Farmers, in turn, would likely struggle to grow important crops like corn, wheat and rice.

鈥淚f we ran out of food on land, would we have enough food in the ocean to feed the world鈥檚 populations?鈥 said Lovenduski, also of the (INSTAAR) at 抖阴旅行射 Boulder.

She and her colleagues wanted to find out. To crunch the numbers, the team first used complex computer simulations to estimate how a large-scale nuclear war could affect what Lovenduski called 鈥渢he thing that everybody else in the ocean eats.鈥

That means plankton鈥攐r floating organisms, from single-celled algae to tiny crustaceans like krill. Like corn plants, many of these organisms need sunlight to thrive.

鈥淏ecause the amount of sunlight reaching the surface of the ocean is reduced so much, the growth of plankton is also reduced,鈥 she said.听

The team discovered that a full-scale nuclear conflagration, such as a fight between the U.S. and Russia, could shrink the growth of plankton around the world by almost 40%.听

Emptying seas

A lot of fish could go hungry as a result. But what happened next would likely depend on people, said Scherrer, a fisheries scientist.

If humans fished like normal after such a globe-altering event, hauls of wild-caught fish might fall by anywhere from 3-30% in the decade after a nuclear war, depending on the severity. That could amount to tens of millions of tons of lost seafood every year.听

But these losses are not inevitable. Many fisheries around the world are already struggling because of overexploitation, climate change and other factors. If these resources were all managed sustainably, however, they could act as a much more reliable source of food. Such healthy fisheries might even be able to replace roughly 40% of the protein that humans currently get from land animals for a few crucial years.听

鈥淚 was surprised by how big those numbers were,鈥 Scherrer said. 鈥淚t鈥檚 a great challenge to effectively manage the world鈥檚 fisheries, but this shows that beyond all the other benefits, strong management would also help to buffer against global food crises.鈥

The team鈥檚 findings carry extra meaning for the researchers now that the world is in the middle of a different kind of disaster: the coronavirus pandemic. Lovenduski remembers walking through grocery stores in March and seeing completely empty shelves.

鈥淚t was terrifying to live in that world,鈥 Lovenduski said. 鈥淚t made me wonder if we are prepared for a disaster like a nuclear war as a global society. I think the answer is 鈥榥o.鈥欌

Cheryl Harrison, a former research associate at INSTAAR now at the University of Texas Rio Grande Valley, was also a lead author of the new study. Other coauthors include听Brian Toon, a professor in the Laboratory for Atmospheric and Space Physics (LASP) at 抖阴旅行射 Boulder, and听researchers from the Autonomous University of Barcelona, University of Texas Rio Grande, U.S. National Center for Atmospheric Research and Rutgers University.