A small conflict in which two nations unleash nuclear weapons on each other could lead to famine. Burning cities would encircle the planet and reflect the sun's rays back into space. In a worst-case scenario, 5 billion people could die because of crop failures.
Lili Xia is a climate scientist at Rutgers University who led the work. I think it is really bad.
The latest thought experiment about the global consequences of nuclear war was published in Nature Food. Russia's war against Ukraine has disrupted global food supplies and is an example of the far-reaching impacts of a conflict.
Nuclear war has a number of lethal impacts, from killing people directly in atomic blasts to the effects of radiation and pollution. They wanted to look at how people all around the planet could be affected by war.
After a nuclear war, they modeled how climate would change in different parts of the world. The scientists analysed six war scenarios, each of which would put different amounts of soot into the atmosphere.
Between 5 million and 47 million tons of soot could be lofted into the atmosphere by a nuclear war between India and Pakistan. 150 million tons of soot could be produced by a full-out nuclear war between the US and Russia. The globe-encircling pall would persist for a long time.
After a nuclear war, the number of calories available for people to eat would be affected. The scientists looked at a number of options, including whether people continued to raise livestock or if they diverted crops meant for livestock to humans. The study assumed that people would cut back on or eliminate food waste if it were assumed that there would be some use for the crops in the future. It was assumed that international trade would stop as countries decided to feed their own people.
Many assumptions and simplifications are used in the study about how the global food system would respond to a nuclear war. The numbers are not easy to read. In the first five years after the war in India and Pakistan, calories production across the planet could go down by 7 percent. The global average calories go down by up to 50%. In the worst case of a United States–Russia war, the production of calories plummets.
The nations at mid to high latitudes already have a short season for growing crops and would be the most affected by a nuclear war. India that is located at lower latitudes would see sharper drops in food availability than the UK that is located at higher latitudes. France, which is a major exporter of food, would be better off if trade were stopped because it would have more food to sell to its own people.
Australia is also less affected. Australia relied on wheat for food in the aftermath of a nuclear war. In the cooler climate, wheat would grow well. Even in the most severe war scenarios, Australia is still green on the team's map. The first time I showed my son the map, he said "let's move to Australia"
The study will help understand the global food impacts of a regional nuclear war. There is more work that needs to be done to accurately model how crops are produced in different parts of the world. The research took into account national crop production numbers, but reality is much more nuanced, with different crops being grown in different regions of a country for different purposes
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Nuclear war seems less threatening than it did during the cold war, but there are still nine countries with more than 12,000 nuclear warheads. Understanding the consequences of a nuclear war in detail could help assess the risks.
If it happens, it affects everyone. These are not safe.
The article was first published on August 15th, 1992.
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