TLDR: Key Points

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1. Urban Agriculture Contributes but isn't Sufficient: Urban agriculture alone could feed ~20% of New Zealand's urban population post-catastrophe, but requires supplementation.
2. Near-Urban Agriculture Completes the Picture: Adding optimised near-urban agriculture requires surprisingly little land (~1,140 hectares for a city of 90,000 people) to achieve food self-sufficiency.
3. Crop Selection is Critical: The most efficient crops vary by scenario - peas and potatoes in normal climatic conditions; sugar beet/spinach and wheat/carrots during nuclear winter.
4. Export Diversion Provides a Buffer: New Zealand's food exports could feed 3.9× its population (1.5× even in nuclear winter), but are primarily dairy which requires much more fuel to produce (eg, compared to wheat).
5. Fuel Dependency is the Achilles' Heel: New Zealand would run out of stockpiled liquid fuel after around 160 days in a prolonged catastrophe.
6. Biofuel Solution is Viable: Just 4,400 hectares of canola (1% of grain-cropped land) could produce sufficient biodiesel to maintain essential food production.
7. Implementation Requires Planning: Success depends on advance preparation including urban land readiness, processing infrastructure, seed availability, and regulatory frameworks.
8. NZ has Strategic Importance: As a potential global refuge after a catastrophe, this country could feed over 8× its population if optimised resilience measures are implemented.

Our new research demonstrates that with relatively modest investments and strategic planning focused on urban/near-urban agriculture and local biofuel production, New Zealand could significantly enhance its food security resilience during global catastrophes.

‍Our new research on urban and near urban agriculture for food security

Our latest study on urban- and near-urban agriculture, published in the international journal PLOS ONE, completes a series of papers showing how New Zealand could maintain food security during global catastrophes that collapse trade, such as extreme pandemics, nuclear war, or severe solar storms disabling global electrical supply.

When combined with our previous work on New Zealand's export food excess, frost-resistant crops, and agricultural fuel needs, we can now present a more complete food security blueprint—revealing both vulnerabilities and strengths in our food systems that could determine whether New Zealand thrives or collapses in a scenario where global trade ceases.

In the new paper, "Resilience to abrupt global catastrophic risks disrupting trade: Combining urban and near-urban agriculture in a quantified case study of a globally median-sized city", we analyse how scaled-up urban agriculture (UA) combined with near-urban industrial agriculture could help feed a New Zealand city during a global catastrophe.

We established these results through mathematical optimisation for protein and food energy given available land. Urban agriculture yields were drawn from a published meta-analysis, and we calculated potentially cultivable urban land area (particularly home lawns and parks) using Google Earth imagery, as demonstrated in the figure below:

Image credit: (CC BY 4.0) from Palmerston North City Council (2024)

For estimating the near-urban (city fringe) land required to supplement urban agriculture, we referred to our previous optimisation research on minimising land area and liquid fuel requirements in a global catastrophe. We assumed only off-road diesel was needed, not transport fuel, given proximity to the city.

‍Key findings from our new urban food security research

Our analysis reveals that urban agriculture alone could feed approximately 20% of New Zealand's urban population in normal climate conditions (less with the reduced yields of nuclear winter). 

This suggests that urban agriculture will not fully meet a city's food security requirements, though previous studies have shown it can meet fruit and vegetable needs. Additional protein and food energy sources remain necessary.

However, when combined with optimised near-urban industrial agriculture on relatively modest land areas, the entire population of Palmerston North (our case study city) could be fed while significantly reducing transport fuel requirements. Local production of a small volume of liquid biofuel could effectively provide survival-level food self-sufficiency for the city.

We found that:

• The optimal crops for urban agriculture were peas (in normal climate) and sugar beet/spinach (in nuclear winter) in terms of protein and food energy yield per area.
• For near-urban industrial agriculture, potatoes (normal climate) and wheat (97%)/carrots (3%) (nuclear winter) were optimal.
• Relatively little near-urban land—just 1,140 hectares for Palmerston North (~90,000 population)—would be needed to make up the shortfall from urban agriculture. This equates roughly to a ring around the city less than 1km wide, though it could be configured to follow the most fertile nearby soils, or transport routes.
• Just another 110 hectares for a biofuel feedstock such as canola seed could provide sufficient biodiesel to run the necessary agricultural machinery.

The figure below shows the crop optimisation results, expressed as land area needed to meet the protein and energy requirements for one person for one year. The figure shows only the most optimal crops. All other crops required more land area (implying more industrial inputs such as liquid fuel, fertiliser, etc. which might be scarce following a global catastrophe). The top panel assumes a normal climate global catastrophic risk (GCR) scenario and shows that peas in urban agriculture spaces feed more people than other crops, and potatoes grown on the city fringe require the least additional near-urban land. The lower panel assumes a severe nuclear winter scenario.

Figure source: Boyd & Wilson (2025) PLOS ONE; GCR: global catastrophic risk; UA: urban agriculture.

These results are illustrated schematically in the next figure, showing that we identified 730 hectares of potential urban agricultural land within Palmerston North. An area of at least 1250 hectares (39% the size of the built urban environment) is needed near the city to produce the rest of the required food and a biofuel feedstock in a no-fuel scenario.

Figure source: Boyd & Wilson (2025) PLOS ONE; UA: urban agriculture.

‍Building on our previous research

This work complements our earlier papers exploring different aspects of New Zealand's food and energy resilience to global catastrophes:

‍Diversion of Food that NZ Currently Exports: New Zealand's current food exports provide more than 3.9 times the dietary energy needed for the entire population. Even in a severe nuclear winter scenario with agricultural productivity reduced by up to 61% (as estimated for NZ in a global study), diverted exports could still provide 1.5 times current New Zealand dietary energy requirements. The challenge is that production is largely dairy milk solids, which require much more liquid fuel and land to produce than crops like wheat.

Frost Resistant Crop Production: We identified optimal combinations of frost-resistant crops for nuclear winter scenarios. The most land-efficient options were wheat and carrots; sugar beet; oats; onions and carrots; cabbage and barley; canola and cabbage; linseed and parsnip; rye and lupins; swede and field beans; and cauliflower. Under current production levels of wheat and carrot, there would be a 71% shortfall in a severe nuclear winter scenario. But although 117,000 ha of a wheat (97%) and carrots (3%) combination could feed all New Zealanders in normal conditions, 300,000 ha is needed in severe nuclear winter. This contrasts with current wheat production of just 45,000 ha (NZ currently imports much of its wheat from Australia).

Mitigating Imported Fuel Dependency: This previous study in the journal Risk Analysis highlighted that New Zealand uses over 3.7 billion litres of diesel annually but has limited onshore stockholdings. Agriculture alone consumes 295 million litres per year. Our modelling showed that the 'bare minimum' liquid fuel requirements for agricultural production would require between 0.14% and 2.8% of New Zealand's total annual diesel consumption, depending on crop selection, transport distances, and climate conditions (including nuclear winter). The graph shows how different the liquid fuel requirements are to supply protein and food energy based on food production type.

Figure source: Adapt Research (2025)

NZ's National Fuel Security Study

The Government’s recently commissioned New Zealand Fuel Security Study modelled a "severe disruption" with complete cessation of fuel imports for 90 days. Essential services and critical government functions would require approximately 5% of normal diesel demand for lifeline utilities and potentially another 5–15% for critical transport (totalling up to 20% of business-as-usual demand). 

However, as we detailed in a blog, the study doesn't include off-road agricultural fuel needs, which would add up to 2.8% more diesel (as we’ve noted above, eg, 107 million litres for dairy production under nuclear winter), resulting in as much as 22.8% for essential needs. It could be that this remains an underestimate as the interdependencies among essential and ‘non-essential’ services are not well understood. 

The Study concludes that New Zealand could manage a 90-day period with no liquid fuel imports, but our estimates indicate that even with judicious use of stockpiled diesel, the country would run out after approximately 160 days. If a catastrophe prevents fuel imports beyond this timeframe, even with reduced consumption, New Zealand would still run out of onshore liquid fuel. This "point of breakdown" isn't apparent from the government's commissioned analysis, highlighting a critical blind spot in national resilience planning.

The Biofuel Solution

Our most significant finding is that New Zealand could achieve a sustainable fuel supply for essential agriculture through relatively modest domestic biofuel production. 

We illustrate this in the following figure, which contrasts current wheat, potato and dairy production land areas, and shows the land required for a biofuel feedstock like canola seed to ensure liquid biofuel for farm machinery and transportation (in our normal climate, short transport distances scenario).

• Just 4,400 hectares (ha) of canola (approximately 1% of currently grain-cropped land) is needed to produce sufficient biodiesel to sustain wheat cultivation equivalent to feeding the entire population
• A refining capacity of just 5-15 million litres of biodiesel annually could maintain this minimum food production (varying according to transport distances and crop selection, eg, wheat vs potatoes).
• Canola is already grown commercially in New Zealand for producing food oil and has previously been refined for biodiesel
• Canola is also relatively frost-resistant, making it suitable for nuclear winter scenarios

Figure source: Boyd & Wilson (2025) PLOS ONE.

The National Fuel Security Study done for the New Zealand Government, included biofuels as a potential solution but found it expensive compared to increasing liquid fuel storage or distribution capacity. However, neither of these alternatives is a long-term solution. We suggest analysing small-scale, local, modular biodiesel production and processing units that could provide distributed resilience.

Putting it all together

Combining our studies, several strategies for increasing food security and reducing vulnerability to liquid fuel shocks emerge. Focusing on highly efficient crops and growing them near processing and consumption centres reduces transportation fuel demands. Scaling up urban agriculture in city green spaces along with expanded production of high-yield crops on city-adjacent land further minimises liquid fuel demand. This approach would bring agricultural fuel and transport demands within reach of a modestly enhanced locally produced liquid biofuel capacity, providing sustainable food production and transport through an ongoing global catastrophe.

We're not suggesting a complete biofuel economy, but rather exploring small-scale biofuel production, with a transition to less land-hungry food production processes (eg, more balance between dairy and wheat), with production closer to processing and consumption, and more urban agriculture. This approach would reduce cultivated land area, fuel consumption, and climate emissions.

Figure source: Adapt Research (2025); UA (%): percentage of within city green space used for crops; BAU: business-as-usual off-road agricultural diesel consumption - for reference (includes export food production); L: litres; ha: hectares.

Figure Key Insights:

• Urban agriculture combined with near-urban crops significantly reduces both fuel needs and land requirements
• Potatoes are the most land-efficient crop (84,000 ha vs 117,000 ha for wheat/carrot)
• Wheat/carrot combination is the most fuel-efficient (5.4 million L at 20km transport vs 21.9 million L for potatoes at 100km)
• Both analyses show major efficiency improvements in terms of fuel and land use compared to business-as-usual dairy production

Implementation opportunities

Successfully implementing these food resilience strategies would require addressing several practical challenges:

• Logistics and agreements for diverting excess export food to the domestic market during trade collapse
• Production of seed (especially frost-resistant crops) and agricultural inputs
• Preparation of urban land for cultivation, and development of expertise
• Processing infrastructure for optimal crops and biofuel feedstock (locally)
• Land use planning including better integration of agricultural production potential into urban and near-urban planning policy
• A comprehensive national fuel security plan that considers catastrophes
• Including food insecurity in the National Risk Register

The Department of the Prime Minister and Cabinet’s (DPMC's) Risk and Resilience Framework sets the expectation for decisive, impactful action to prevent or reduce potential crises – all of the above could be tested and implemented for global catastrophe resilience.

It's time to start pilot programmes in New Zealand, testing the feasibility of these approaches to food and fuel security. Which New Zealand city will become the world's first median-sized city that is self-sufficient for basic food needs in a catastrophe?

Much could be done through developing plans, regulatory levers, incentivising appropriate agricultural processes, and with targeted government support. The tension between efficiency and resilience runs through this research. Our modern systems are optimised for efficiency under normal conditions but may be extremely vulnerable to disruptions. Building resilience often requires maintaining seemingly redundant systems as insurance against catastrophe. Yet ensuring a minimum food supply for the population during major global catastrophes is arguably a core government responsibility.

Conclusion

It is concerning that New Zealand would run out of liquid fuel (hindering food production and transport) beyond a few months in an ongoing global catastrophe. It's also concerning that there is insufficient cultivation of frost-resistant crops to handle abrupt sunlight reduction (nuclear, volcanic, or asteroid/comet impact winter).

However, a surprisingly small volume of liquid fuel is required for food production if steps are taken to ensure minimal cultivation of high-protein, high-energy, fuel-efficient crops near processing and consumption areas. Transport and fuel demands can be further reduced by scaling up urban agriculture and cultivating optimal crops within cities and adjacent to them. A small amount of locally produced liquid fuel could then sustain these processes without global trade.

Our findings suggest that with modest investments and strategic planning, New Zealand could significantly enhance its ability to avoid famine during even severe global catastrophes that disrupt fuel supplies.

These issues are particularly salient for New Zealand as an island nation. New Zealand can potentially feed eight times its population through food exports of the most efficient crops if these can be sustained through catastrophe. New Zealand is also often cited as a potential 'refuge' for humanity where societal complexity might persist through a global catastrophe. Securing sustainable fuel supply for essential functions, alongside accelerating electrification, is central to this vision. Collaboration with other regional food-producing islands like Australia would be prudent.