Nuclear war could starve to death up to 80% of the world’s population

Even a relatively small nuclear conflict involving two sides can lead to worldwide starvation. The new study, published on August 15, 2022, is the most extensive simulation of nuclear winter resulting from nuclear war to date. It studies the impact of nuclear conflict primarily on cold famine in the next few post-war years.

Briefly about the consequences of nuclear war

Nuclear bombs aimed at cities and strategically important industrial areas will lead to massive fires, which the study calls firestorms. Huge fires will send millions of tons of soot into the atmosphere, which will scatter all over the planet and reflect some of the sunlight back into space. The decrease in sunlight received will lead to a sharp cooling of the entire planet and severe climate disruption for decades. The cold will lead to global crop failures that, in the worst-case scenario, could kill more than 5.3 billion people.

People who are relatively close to the explosions, but did not die directly from them, will receive great damage from radiation. Survivors may experience radiation sickness. A nuclear war would pollute the soil and water near the explosions, making it uninhabitable and unsuitable for growing food. In addition, the situation may lead to riots, looting, and food wars, which will further affect the production and distribution of food.

* Most comprehensive food data available for 2010. Therefore, the authors took them and made calculations in relation to the population for the same year. 5.3 billion out of 6.7 billion people (population in 2010) is approximately 80%. So many people can only die of starvation as a result of a nuclear war.

Nuclear war will lead to severe cooling

Scientists have long known that violent explosions can release enough dust, ash, and soot into the air to affect the climate of an entire planet. It is impossible to win in such a war — soot will be carried by air masses all over the Earth and will affect all countries of the world without exception. However, different countries will receive different degrees of damage, which we will discuss below.

There have already been catastrophes in the past that caused only a small fraction of the damage compared to the possible damage from a nuclear war:

• In 1815 there was a major eruption of the Tambora volcano in Indonesia. The country is located on the islands of Southeast Asia, but the ash from the volcano rose into the air and spread throughout the planet, blocking sunlight even in Europe. In history, 1816 is known as the “year without summer”, when a severe cold snap led to massive crop failures and famine around the world.
• In 1783 there was a major eruption of the Laki volcano in Iceland. The consequences were similar, the ash from the eruption reached Europe and America. And in Iceland itself, the cataclysm caused political instability and massive famine, which killed 20% of the country’s population. In 1784, the aftermath of a volcanic eruption led to crop failures and famine in Europe.
• In 2017 Canada and in 2019–2020 Australia experienced severe wildfires. They led to the formation of 6–20 thousand tons of soot. Subsequently, smoke from forest fires in Canada rose to a height of 12–23 km and lasted for 2 months, and then it remained in the stratosphere for more than 8 months. For comparison: nuclear war in 6 different research scenarios can cause not 6–20 thousand tons, but 5–150 million tons of soot, which is 250–25,000 times more!

Calories will be very important during nuclear winter

Now there is a lot of talk about how to cut calories when eating so as not to gain excess weight. In times of nuclear winter, the opposite is true: calories can be severely lacking. Some people will be forced to reduce their physical activity so that the food they consume does not lead to weight loss over the next few years. Other people will only have enough food to consume calories below their basal metabolic rate, even if they are sedentary. This will lead to a prolonged (and sometimes dramatic) weight loss up to death.

Even with the great importance of calories, it is worth remembering that proteins and trace elements will still be important for people to survive the next years in conditions of food shortage.

Crops are the main source of calories for people and livestock

Most of the calories in the world come from agricultural crops.

• 51% of all calories are grains. But many crops (for example, a significant part of corn or soybeans) are used for animal feed.
• 31% — vegetables, fruits, root vegetables, tubers, and nuts.
• 18% are products of animal origin, with only 7% coming from the fishing industry, including 3% from wild marine catches.

A severe cold snap will lead to the impossibility of growing or a strong reduction in the cultivation of many crops in countries where the weather was already not the warmest. It will not be possible to replace these crops with animal food since the livestock will also not have enough food. Most likely, the opposite effect will occur: crops previously used for animal feed will be consumed by people due to food shortages.

You can only slightly reduce the problem of lack of calories over the next few years

There are at least 3 solutions to the situation, but they will help feed more people only locally and in individual cases.

1. Use crops to feed livestock as food for people. This can partially compensate for the lack of food only in some local regions. Overall, this will have only a limited effect on the total amount of food in the world. With a large amount of soot in the air, the growth of fodder crops will be seriously impaired, so both people and animals will starve.
2. Cut down on food expenses. In other words, consume food more sparingly and do not throw away part of the food (the world's average household waste is about 20% of all calories). But this approach will only be effective in the event of a small nuclear war. In the event of a major nuclear conflict, the amount of food will be significantly reduced due to a very cold climate, and such tactics will not solve the problem of global hunger.
3. More animal husbandry and fishing. But they are able to compensate for the loss of food production from crop production only in very limited parts of the world.

Distribution of food products across countries is another problem

Already, global food production is able to feed even more people than there are on Earth. However, 700–800 million people still suffer from malnutrition (data for 2020). Our civilization, even in relatively peaceful times, could not distribute the available food so that there was no hunger on the planet.

In a nuclear winter, food shortages are likely to lead to very severe restrictions or to a complete halt in food exports to countries in need. Each country will be forced to solve the problem of hunger in the population on its own. It is this scenario that scientists considered in their work.

Based on past experience, it can be assumed that the distribution of food is unlikely to be fair, not only between countries (if at all) but also within countries, if they continue.

Nuclear war scenarios

The 2 most likely conflicts were considered:

• A nuclear war between NATO countries and Russia accounts for more than 90% of the world’s nuclear arsenal.
• A nuclear war between India and Pakistan over the disputed region of Kashmir. (In the Russian-language news, this conflict is rarely talked about, it is important to understand that it is quite serious and there really is a possibility of a nuclear war between these two nuclear powers).

A total of 6 war scenarios were analyzed. All of them assume nuclear war within 1 week. A nuclear conflict will result in the release of 5 to 150 million tons of soot into the atmosphere, which will lower the surface temperature of the planet from 1 to 16 °C. The climatic effects of such a war could be felt for decades or more.

Consider three scenarios: the least dangerous, intermediate, and most dangerous.

• The smallest nuclear conflict between India and Pakistan. 100 warheads with a capacity of 15 kt (kilotons) will lead to the release of 5 million tons of soot into the atmosphere. This will lead to a reduction in the production of calories on the planet by 7% in the next 5 years after the war. 27 million people could die directly from the explosion and another 255 million from starvation in the next 2 years.
• The large-scale nuclear conflict between India and Pakistan. This time, 500 100 kt warheads will kill 164 million people. Nuclear bombs would cause the release of 47 million tons of soot into the atmosphere, which would reduce the production of calories by as much as 50%. 2.5 billion people could die due to hunger in the next 2 years.
• The worst-case scenario with a large-scale nuclear war between NATO countries and Russia. France, Germany, Japan, Great Britain, the USA, and Russia will undergo nuclear attacks in the scenario. 4400 warheads of 100 kt can kill 360 million people. As a result of explosions, 150 million tons of soot will be released into the atmosphere. Due to a severe cold snap, calorie production will be reduced by as much as 90% in the next 3–4 years. As a result of famine in the next 2 years, up to 5.3 billion people will die.

All 6 scenarios are presented in the table in the study source. There are many other scenarios involving North Korea, Israel, China, and other countries. However, the purpose of the study is not to calculate them all, but to provide a clear example of the possible risks of a nuclear war.

Which countries will be affected the most?

It is important to understand that the soot in the atmosphere will spread throughout the planet, so there will be no winners, and everyone will suffer. But different countries will be affected to varying degrees.

Countries in the high and middle latitudes will suffer the most. These concerns primarily the countries of the northern hemisphere with a short season for growing crops. A severe cold snap will lead to a strong decrease in productivity, many crops will freeze.

Between the green and orange lines are the middle latitudes. Above the orange line in the north and below the orange line in the south are high latitudes.

North hemisphere. Canada, the US, the UK, and Russia will see a much larger decline in yields (by 30–86%) than in India (by less than 10%) located at lower latitudes. And since the United States and Russia are also major food exporters to other countries, many other countries will suffer due to a strong decline in yields.

In a less dangerous scenario, France, which is a major food exporter, will have the most food for its own population among the countries of Europe.

Southern Hemisphere. Countries in the southern hemisphere as a whole will suffer less due to their climate. However, in almost all countries, in the event of the most serious nuclear conflict, part of the population will be undernourished. The exception is Australia. It is one of several countries that will be the least affected by nuclear winter. For example, wheat in Australia could grow well and provide almost 50% of the country’s calorie production even with a severe cold snap in a worst-case scenario.

Argentina and New Zealand will also be less affected than many other countries. Also on the list of exceptions are three small countries in the north of Brazil: Guyana, Suriname, and French Guinea. Brazil itself will also suffer not as much as many other countries, but more than the countries listed before.

Unaccounted for factors

The study did not take into account all factors. The authors themselves suggest adding a few more.

What can make it worse:

• taking into account the impact of soot on ultraviolet radiation and the ozone layer;
• reduction in the population due to a decrease in the birth rate in a nuclear winter;
• a decrease in the labor force, which will affect the production and distribution of food;
• political instability, food warriors, looting, etc.

What can partially improve the situation (the authors note that these changes will take a long time):

• gradual transition to more cold-resistant crops and more widespread use of greenhouses;
• growing and using other food sources such as mushrooms, seaweed, insects, methane single-cell protein, and cellulose sugar (growing foods that do not require much light in conditions of extreme cold will be especially useful).

Nuclear war must be avoided at all costs

As the authors note, the results of the study once again confirm the statement made in 1985 by Soviet Secretary General Mikhail Gorbachev and US President Ronald Reagan, and then repeated by other leaders, that “there can be no winners in a nuclear war and it should never be unleashed”. It is important that this statement be manifested not only in words but also in deeds.

Sources:

1. https://www.nature.com/articles/s43016-022-00573-0 (study, 08/15/22)
2. https://www.nature.com/articles/d41586-022-02219-4 (analysis of the study, 08/15/22)
3. https://www.science.org/content/article/nuclear-war-would-cause-yearslong-global-famine (another research review, 8/15/22)

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I would like to thank Yury Erofeev from SQUAKE for preparing the publication.