A new study suggests New Zealand would still be able to produce enough food to feed our entire population even in a nuclear winter - but a lack of imported goods could still cause major disruption.
The study by Nick Wilson, Marnie Prickett and Matt Boyd was published in the New Zealand Medical Journal on Friday. In it the authors looked at New Zealand's current food production, including exports, and how three different nuclear winter scenarios would affect it.
At the moment major food exports are 3.9 times the dietary energy needs for all New Zealand citizens. This translates to roughly 8150 calories per person per day, well above what's necessary.
Exported dairy products were estimated to be able to provide 338 percent of this, followed by exports of meat (34 percent), fruit (8.6 percent), alcohol (4.8 percent), marine products (4.6 percent) and vegetables (2.7 percent).
The first and least severe nuclear winter scenario the authors considered was a nuclear war between India and Pakistan. In this scenario, they estimated an eight percent reduction in major food crops and marine fish in New Zealand. The second scenario was a war between NATO and the then Warsaw Pact which they estimated would result in a 28 percent reduction. The last and most severe scenario was a war between Russia and the United States and its allies. In this scenario the authors estimated agriculture production would drop by a whopping 61 percent.
During the various nuclear winter scenarios considered, food production available from diverted exported foods was estimated to still be between 3.6 to 1.5 times the daily need.
But the authors warned the agriculture sector could be at risk of various levels of collapse from lack of imports such as diesel, fertiliser, pesticides, seeds, and machinery parts, and from socio-economic collapse including if the financial system fell apart.
While theoretically, New Zealand could produce enough food, the study pointed out transporting the food around the country could become problematic due to a lack of petrol and diesel.
"Food is transported internally in New Zealand by rail, truck and van. Except for the North Island Main Trunk railway and suburban rail systems (which are electrified), these transport modes are highly dependent on imported liquid fossil fuels," the authors noted.
"The exploratory work in New Zealand on electric-milk tankers and hydrogen-powered trucks is still at a very early stage. In a post-war setting, some existing electric cars and vans could be repurposed for food delivery, but possibly food production would need to be intensified closer to cities and towns.
"Severe fuel shortages could require a return to cattle drives where cattle are herded along roads from farms to abattoirs in towns and cities."
Finance was another issue, with the authors noting a nuclear winter would likely see the financial system collapse. Unemployed and retired people would still need money to buy food which means central and local governments might need to have backup food rationing systems and systems for prioritising food supplies to essential workers and those at greatest need. "Fortunately, the New Zealand Government obtained some valuable experience with rapidly providing mass welfare support during the COVID-19 pandemic—but the scale of a post-nuclear war situation would probably be vastly greater and longer lasting," the authors noted.
"Appropriate financing may also be needed to assist the agricultural sector in diverting crops suitable for human food that are currently used for animal feed and other purposes. For example, an estimated 78 percent of cereals produced in New Zealand are used for livestock feed. Furthermore, some of the remaining 22 percent of cereals could be used more efficiently to feed humans, e.g.,if more of the barley crop was used for making flour rather than being used to make beer and spirits.
"Fodder beet (a type of beetroot) and forage brassicas (e.g. canola, radish, turnip, swede, and kale) could also be converted from stock feed to human food. Alternatively, this forage cropping land could be used for other food crops."
Along with transporting food, fuel would be needed to run some agricultural machinery, which wouldn't be widely available in a nuclear winter scenario.
The study noted substitutes for diesel are minimal and the end of oil refining capacity of the Marsden Point refinery in 2022 closed off one source of partial fuel self-sufficiency.
Industrial materials such as fertiliser, pesticides, animal health pharmaceuticals, and spare parts for agricultural machinery are also often imported which would cause issues.
And although New Zealand does make some of its own nitrogen fertiliser, it is dependent on imports for phosphate-based fertiliser. The capacity to manufacture replacements for imported materials is uncertain, the study warned.
Despite the challenges though, the study found even in the most severe nuclear winter scenario where food production is reduced by 61 percent, diverted food exports could still provide 1.5 times the needed daily food for New Zealand's population (3178 calories per person per day). In the much smaller regional nuclear war scenario where food production is impacted by just 8 percent, diverted food exports could still provide 3.6 times the needed food.
"This preliminary analysis suggests that New Zealand’s current food production for export is
theoretically able to provide an excess of dietary energy for the whole population, even after a severe nuclear winter that reduced food production across-the-board by 61 percent. As such, this baseline excess food production capacity would also be a resilience factor after other sunlight-reducing planetary catastrophes such as large volcanic eruptions and asteroid/comet impacts.
"Furthermore, given the breadth of food production in New Zealand, there are no survival-critical food products that would be missing from the national diet after such catastrophes. At any point in time, some of these exported foods are already available in warehouses and in shipping containers awaiting export. For example, if 10 percent of annual export production is in this pre-export state, it would be enough to provide dietary energy for all New Zealand citizens for around 4.7 months (if appropriately distributed)," they said.
But the authors said despite this New Zealand's agriculture sector is extremely interconnected with other key systems in modern society which puts it at risk of various levels of collapse from lack of imports. Similarly, if the financial system collapsed, then farmers would not be paid for food production, and they may shift to providing for themselves and bartering.
If post-war trade was able to be re-established with regional neighbours such as Australia and
Indonesia, then these countries could provide some liquid fuels and machinery parts used for food production in New Zealand.
If so, New Zealand could strive for some ongoing food exports to these countries so that imports could be paid for.
Trade with Pacific Island nations could include the export of coconut oil, sugar and dried fish to New Zealand, with coconut oil also being a potential diesel substitute.
The authors also noted while some studies suggest there could be an influx of refugees to New Zealand and Australia after a nuclear war, a lack of access to shipping would "substantially constrain" arrivals.
The authors said overall the analysis suggests New Zealand could theoretically have excess food production capacity, even after a severe nuclear winter scenario.
But they said this benefit could be very short-term if the agricultural system was not made more resilient to a potential lack of international trade and socio-economic collapse in a post-catastrophe setting.