Food security during nuclear winter: a preliminary agricultural sector analysis for Aotearoa New Zealand.

Aim: 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.

Methods: From published sources we estimated dietary energy available from the major domains of food exports, with adjustments for wastage. The impacts on food production in New Zealand during three nuclear winter scenarios were based on those published in Nature Food in 2022 and from an earlier New Zealand Planning Council study.

Results: Current major food exports are equivalent to 3.9 times current dietary energy intakes for all New Zealand citizens i.e., 34,100 kJ (8150 kcal) per person per day. Exported dairy products were estimated to be able to provide 338% of this energy intake, followed by exports of meat (34%), fruit (8.6%), alcohol (4.8%), marine products (4.6%) and vegetables (2.7%). During the various nuclear winter scenarios considered (minimal to severe), food production available from diverted exported foods was estimated to still be 3.6 to 1.5 times current daily energy intakes. Nevertheless, the agriculture sector could be at risk of various levels of collapse from lack of imports (e.g., diesel, fertiliser, pesticides, seeds, and machinery parts) and from socio-economic collapse, including if the financial system collapsed.

Conclusions: This analysis suggests that this country could theoretically have excess food production capacity, even after a severe nuclear winter scenario. But this benefit could be very short-term if the agricultural system was not made more resilient to potential lack of international trade and socio-economic collapse in a post-catastrophe setting.