The conflict between Russia y Ukraine has revived the ghosts of nuclear war: first the occupation of the sarcophagus that isolates Chernobyl and, later and more recently, the fighting near the Ukrainian plant of Zaporizhia, whose situation is, according to the United Nations Security Council, “critical”, have caused all the alarms to go off. Now, a study published in the journal ‘Nature Food’ warns about the danger and devastating consequences of six possible scenarios of nuclear war. Worst of all, a conflict between USA and Russia, which would cause 5,000 million deaths from famine alone, without taking into account direct deaths or other causes.
Building on data from previous research, a team of international researchers led by Alan Robock y Lili Xia, both professors at the Department of Environmental Sciences at Rutgers University (USA), determined the amount of ash and soot that would be created after the detonation of nuclear weapons and how all this material could block the sun from entering the atmosphere. The authors calculated soot dispersion from six possible war scenarios between the nuclear powers (five small conflicts between India y Pakistan and a large-scale one between the US and Russia), taking into account the size of each country’s arsenal.
This information was fed into the Community Earth System Model, a climate forecasting tool supported by the National Center for Atmospheric Research (NCAR), allowing calculations of how it would affect the productivity of the world’s major crops (corn, rice, wheat and soy). The researchers also examined the projected changes in the grasses of the livestock and in the fishing at the global level.
And the answer was clear: even in the smallest nuclear scenario – a localized war between India and Pakistan – it would see crop yields decline by 7% within five years of the conflict. In a ‘small’ conflict (about 100 detonations), 5 million metric tons of particles would be thrown into the atmosphere. For comparison: the catastrophic forest fires in California in 2017 or those in Australia at the end of 2019 reached up to 1 million metric tons each.
This ‘umbrella’ of ashes would affect crops and, on average, we would have access to 7% fewer calories. In the developed Western world this may seem like a small thing; however, in countries bordering on systematic famine, this would be a death sentence.
The data is even more alarming in the case of a large-scale war between Russia and the US, where global caloric production would drop to 90% just three or four years after the detonations, since some 150 metric tons of ash and dust. “The data tells us that we must prevent a nuclear war from happening,” says Robock.
Catastrophic market disruption
Crops in mid and high latitudes would be the most affected by this ‘screen’ of ash. The UK, for example, would see steeper drops in available food than a country like India, which is at lower latitudes. But France, which is a major food exporter, would do relatively well, at least in the lower emissions scenarios, because if trade were to stop, it would have more food available for its own people.
The map on the left is the state of calorie consumption in 2010 without international trade; the left column is the Livestock case; the middle column is the case of Partial Livestock, with 50% of livestock feed used for human food and the other 50% for livestock feed; and the right column is using all the available food. All maps assume that there is no international trade and that total calories are evenly distributed within each nation. Regions in green mean that food consumption can support current physical activity in that country; regions in yellow are calorie intake that would cause people to lose weight and only sedentary physical activity would be supported; and regions in red indicate that daily calorie intake would be less than needed to maintain a basal metabolic rate (also called resting energy expenditure) and thus lead to death after a person depleted their stores of body energy into stored fat and expendable muscle. From top to bottom, metric tons of ash ejected into the atmosphere.
Another ‘lucky’ nation would be Australia. Cut off from trade in the wake of a nuclear war, Australia would rely primarily on wheat for food. And wheat grows relatively well in the cooler climate induced by atmospheric soot. On the team’s map showing large portions of the world colored red, due to famine, Australia shines an unbroken green, even in the most severe theaters of war. “The first time I showed my son the map, his first reaction was ‘let’s move to Australia,'” says Xia. Spain does not fare badly in the distribution either, although it would directly notice the consequences in the event of a generalized war.
However, in a globalized world, it is impossible to think that the entire world would not be affected: “These changes would induce a catastrophic disruption of global food markets,” the authors write. Even a 7% global decline in crop yields would exceed the largest anomaly ever recorded since records began, dating back to 1961. “Under the largest war scenario, more than 75% of the planet would be starving.” two years from now,” say the researchers.
The authors also considered whether feeding livestock feed or reducing food waste could offset losses. However, it was not an impact measure in the case of major nuclear conflicts. Also, farming patterns would change. For example, the ozone layer would be destroyed by heating of the stratosphere, producing more ultraviolet radiation at the surface. “Or the effect that the death of pollinators would have. That is why we need to understand those kinds of impacts on the food supply,” says Xia.
The need to end nuclear weapons
Robock claims that this work, in which researchers from the Autonomous University of Barcelona also participated, is irrevocable proof that a nuclear war, regardless of its size, would destroy global food systems, killing billions of people in the process. .
In fact, it is not the only study that warns about the risk of a nuclear conflict. An investigation published last month in the journal ‘AGU Advances’ indicated that, in the event that two states with nuclear potential entered into combat -regardless of which of the nine that currently possess this weapons capacity-, a catastrophe would occur: the Earth’s temperatures would drop ten degrees Celsius, crops would fail around the world, sea ice would block major ports, and fishing would virtually disappear.
“If nuclear weapons exist, they can be used, and the world has come close to nuclear war several times. Banning nuclear weapons is the only long-term solution. The five-year-old UN Treaty on the Prohibition of Nuclear Weapons has been ratified by 66 nations, but none of the nine nuclear states. Our work makes it clear that it is time for those nine states to listen to science and the rest of the world and sign this treaty.”