By Matt Boyd & Nick Wilson

Summary/TLDR
- Recent global events have highlighted the need for resilience planning in the face of catastrophic risks.
- In a new peer-reviewed paper (paywalled, preprint here) we estimate the impact of nuclear winter scenarios on New Zealand’s food export production, finding it dramatically reduced.
- New Zealand’s food supply is a critical variable in resilience, but the country’s ability to feed itself through a global catastrophe is likely to be limited by critical imports such as the supply of liquid fuels needed to power tractors, harvesters and trucks.
- Analysis is needed to examine the most efficient production approach, reliable supply of liquid fuel, and a detailed fuel rationing plan that prioritizes food production/processing/distribution.
- A robust, systematic, National Risk Assessment is needed to identify the most cost-effective and impactful action points to achieve long-term strategic resilience.
- The Aotearoa NZ Catastrophe Resilience Project seeks to map a policy agenda that could help mitigate the cascading impacts of global catastrophes – but this is no substitute for serious Government consideration now.
Risk and Resilience
In the wake of shocks such as Covid-19, the Russian invasion of Ukraine, Cyclone Gabrielle, and many other recent events, resilience has become a central concern for industry and government. Many organisations, including the Ministry of Transport, the Productivity Commission and the New Zealand Infrastructure Commission have turned their attention to resilience issues.
Luckily New Zealand has been able to muddle through these disasters, however, a much more significant global catastrophe could emerge at any time. Such risks include a great power war, nuclear war, more extreme pandemic, massive volcanic eruption, asteroid/comet impact, major solar flare, or a catastrophic scenario precipitated by emerging technologies (eg, artificial intelligence, bioengineering).
Catastrophic disruption to trade in any of these situations could be unbearable for New Zealand. Critically, modelling studies have indicated that in some scenarios (eg, nuclear war, volcanic eruption, asteroid/comet impact) the catastrophe could be amplified because the sun is partially blocked by soot, sulfur dioxide, or dust. Such impacts could last a decade or more.
Civilization and industry flourish thanks to increasing connections (trade), but this leads to increasing dependence. When catastrophe strikes connections can be rapidly lost as the immense impact disables trade, yet dependence remains.
Food supply is a critical variable for resilience and the potential for a society to bear the unbearable. New Zealand produces a lot of food, but production, processing, and distribution are dependent on connections to imports of oil products, fertilizer, seeds, pesticides and equipment.
Although New Zealand has demonstrated its ability to muddle through lower-level disasters, weathering much more impactful global catastrophe, with society and industry relatively intact, is likely to require significant pre-planning and persistent shifts towards resiliency.
Critical Questions
Some fundamental questions include the following:
- How much food does New Zealand produce in normal times and how would production be impacted by global catastrophe (eg, the climate impacts of nuclear or volcanic winter)?
- How much is the production/processing/distribution dependent on connections to the world, and what yield is possible without such connections (also accounting for 1 above)?
- What adaptations might be possible to pivot production/processing/distribution to maximize calories given the conditions?
- What policy agenda ought to be followed to achieve food security for all citizens considering the above?
It is notable that the Draft Food and Beverage Strategy published by the Ministry of Primary Industries (Dec 2022) does not mention risk beyond climate change or commercialization risks, focuses on scale and efficiency, and does not deal with resilience of production sources. The Strategy basically says nothing about how to protect food supply from catastrophe – possibly the single most important factor across the sector.
These omissions could be partly because New Zealand needs a new systematic National Risk Assessment, that examines major global and national risks, and provides information and direction across all of government. There have been repeated calls for this, including from New Zealand’s former Chief Science Advisor Sir Peter Gluckman. We echo these calls and have written elsewhere about the importance and structure of National Risk Assessment.
New Zealand Food Export Calories during Nuclear Winter
We have just published a peer-reviewed analysis that attempts to answer question (1) above. In a paper appearing in the New Zealand Medical Journal (Apr 2023), we aimed to estimate the current dietary energy content of food exports for Aotearoa New Zealand and food security during “nuclear winter” scenarios following a nuclear war.
We combined data from New Zealand nutrition surveys, food export weights from the New Zealand Harmonised System for export data, and data from modelled New Zealand specific nuclear winter impacts. We then determined the per capita caloric supply accounting for wastage, but assuming sufficient industrial inputs (diesel, fertilizer, seed stock, etc)
New Zealand export food production (which accounts for the majority of New Zealand food production, >70%) could be reduced by up to 61% due to the climate impacts following a global nuclear catastrophe. This would mean that instead of supplying the equivalent of 3.9 times (393%) the average daily energy intake of the population (largely in the form of milk powder), export food production would only total 1.5 times (153%) the average calorie intake.
Our paper contains the following table, which illustrates the dramatic drop in export calorie production under the various nuclear winter scenarios and the large concentration of these calories in dairy exports.

Fuel Energy is Critical
Most critically, the results in the table are before any adjustment is made for a potentially catastrophic reduction in the supply of diesel, fertilizer, pesticides, and seed stock. Without diesel to power tractors, milk tankers, and distribution trucks, the ability to supply food calories to all New Zealanders could become marginal.
A plan to pivot export food production to the domestic market would be valuable. This is needed because food produced for the domestic market, when reduced by the likely impact of nuclear winter (excluding the impact of fuel/fertilizer/seed supply etc) could be substantially insufficient to feed the population. Also valuable would be plans to divert crops currently used to feed livestock towards directly feeding humans and to upscale production of frost resistant crops.
It appears that at present the most critical variable in New Zealand’s ability to feed itself through a global catastrophe is likely to be the supply of liquid fuels, which would make or break New Zealand’s food production buffer.
This is where question (2) above comes in. Analysis should now examine how much liquid fuel is needed to ensure the minimum food production, what the most efficient production approach is (this may need to account for the ability of crops to withstand additional frost in a nuclear winter scenario – eg, expanding wheat/carrots as we discuss in our paper on frost resistant crops and nuclear winter) and how New Zealand can achieve this degree of reliable supply of liquid fuel.
A Resilient Solution to Food Security
It is likely that a resilient solution involves some combination of increasing onshore stocks of imported diesel, increasing capability and capacity to produce biofuels (eg, by planning to strategically pivot cropping towards canola to make biodiesel), electrifying machinery and transport, and possibly developing the ability to refine Taranaki crude oil, as a backstop, all in the context of optimizing which crops and production are prioritised.
The above approach needs to be wedded to a detailed fuel rationing plan that prioritizes food production/processing/distribution and identifies quantities consumed per caloric output and rations fuel accordingly. Unfortunately, the current publicly available National Fuel Plan lacks this level of detail. Curiously, the ‘Critical Customer Sectors’ identified for priority fuel include ‘transport and storage of food’ but not ‘food production’. A cursory glance at the priority customers reveals that Corrections, Search and Rescue, and other sectors are prioritized, but these surely are secondary to food production after a global catastrophe. Some more clarity on the details of the Fuel Plan is needed.
To avoid the potential for confusion, conflict and disagreement, the detailed plan needs to be developed with stakeholder engagement and disseminated ahead of time to give society confidence that there is a feasible plan for feeding the nation through a global catastrophe.
A New Zealand Global Catastrophe Policy Agenda
A full policy agenda is beyond the scope of this blog, but it is worth noting a few starting points:
- A single global catastrophe could wreak more harm than all local natural hazards combined. Global catastrophe should therefore be seen as an unbearable situation requiring a strategy and planning (this is evidenced by one event, Covid-19, arguably a relatively ‘minor’ global catastrophe, causing 95% of all disaster deaths globally in the 21st Century to date).
- Other countries have legislated requirements that global catastrophes be analysed. For example, the US Global Catastrophic Risk Management Act 2022 requires cross-agency federal plans for ensuring a bare minimum of essential functions under such circumstances.
- New Zealand should cooperate with other governments on global catastrophic risks. Some problems will be unique to geographic locations (eg, New Zealand is very remote) but others will be common and cooperation will be important (eg, New Zealand and Australia could share food security plans and investigate ways to ensure trade between them continues).
- The New Zealand Government should undertake a robust, systematic, National Risk Assessment. The assessment should seek common catastrophic impacts across a range of nationally consequential risks, to identify the most cost-effective and impactful action points. This would inform long-term strategic resilience projects. The issues described above are just a taste of the potential impacts of global catastrophe and consider only a handful of global catastrophes. A broader systematic approach is very much needed.
As was noted in the independent report on Auckland’s January 2023 flood response, ‘citizens deserve and expect’ that such thinking/planning has been undertaken. This is true for local natural hazards, but it is most true when the consequences would be national and unbearable.
Conclusion
Our analysis of New Zealand food export production during nuclear winter scenarios suggests that there could potentially be excess food production capacity. However, this benefit may only be short-lived if the agricultural system is not made more resilient to potential lack of international trade and socio-economic collapse in a post-war setting. Further analysis is needed to clarify catastrophe impacts on the interlinked domains of energy, transport, manufacturing, finance, industrial materials, trade, and societal functioning.
Our current project, the Aotearoa NZ Catastrophe Resilience Project (NZCat) seeks to map a policy agenda that expands on the above. We have a survey that is currently live, which aims to collect a cross-sector brainstorm of how scenarios such as the above (beyond what risk analysts might have previously considered) might have cascading impacts within and across sectors, and therefore ideas for how to mitigate these cascades and build resiliency. If you wish to contribute to this survey and give your ideas for a more resilient country, please get in touch.