Impacts: Food insecurity
Image: Hasanuzzaman Himel
Home > Climate wiki > Impacts >
Summary
Food security: access to sufficient safe and nutritious food for the whole nation, at all times – even in times of crisis. – FAO
Aotearoa’s main supermarket chains have only a week’s worth of food supply available at any one time. – Resilience Challenge: Food systems security and disaster recovery
The most useful single number in the agricultural literature comes from Hultgren and colleagues (2025), an eight-year study of six staple crops across 12,658 regions, capturing two-thirds of global crop calories. For every degree of global warming, the world loses approximately 120 kilocalories per person per day, about 4.4% of daily consumption. Critically, that estimate is net of adaptation: it already assumes farmers change cultivars, shift planting dates and adjust management in response to the climate they experience, despite the fact that farmers notoriously resist changes to their farming practices. – Hunger at the dinner table, 2026
Global agricultural productivity is 20% lower today than what it could have been without climate change. Extreme heat is already harming crop yields… For every 1 degree C of warming, yields of major crops like corn, soybeans and wheat fall by 16% to 20%, gross farm income falls by 7% and net farm income plummets 66%. – Physics.org 2024
Current policy commitments fall short of preventing agriculture from being the source of about one third of global emissions and at the same time a victim of climate… Incentives to promote more sustainable ways of producing food contend with the challenge of addressing stranded assets at the farm level while offering strong and stable livelihoods. Transforming food systems worldwide provides a uniquely powerful means of addressing the global climate, nature and health emergencies while offering a better life to hundreds of millions of people. – Food Systems Economics Commission 2024
…the reduction in photosynthesis caused by microplastics is estimated to cause an annual loss of 109.73 to 360.87 million metric tons (MT) for crop production and 1.05 to 24.33 MT for seafood production. – Zhu et al 2024
What’s in this page:
What does food insecurity mean for Aotearoa?
While many people may not be “hungry” in the sense that they are suffering physical discomfort caused by a severe lack of dietary energy, they may still be food insecure. They might have access to food to meet their energy requirements, yet are uncertain that it will last, or they may be forced to reduce the quality and/or quantity of the food they eat in order to get by. This moderate level of food insecurity can contribute to various forms of malnutrition and can have serious consequences for health and well-being. – FAO
In 2021, an estimated 15-20% of Aotearoa’s population are impacted by food insecurity:
Rates of food insecurity are much higher amongst Māori and Pasifika peoples, and those with disabilities or living in low-income households. – Evidence presented to the Commerce Commission, August 2021.
In 2026, that number had climbed to 31%.
Aotearoa produces a vast quality of food—food and fibre made up 81% of our exports ($53.3 billion) in the financial year ending 2022. A recent risk analysis undertaken by Lloyd’s, of the global cascading effects of food insecurity could cost New Zealand around $20 billion/per year over 5 years (Figs. 2 & 3).
Cyclone Gabrielle took out apple trees and kumara fields, driving up prices. Drought in Argentina caused a nut shortage, pushing up the cost of peanut butter. Torrential rain during planting season decimated India’s rice crop, leading its government to ban some exports and – you guessed it – led to surging global prices. Shoppers saw these impacts on their supermarket receipts, as food prices increased 8% over the year. – Olivia Wannan, Stuff, 05 Feb. 2024
Food production at risk
The South Island’s snow and ice act as a battery that powers our food systems, by storing water to ensure the rivers can keep flowing and the soil stay hydrated year round. So what does it mean when all that frozen water is melting? – The Spinoff July 2024
Repeated food crises over the past two decades have highlighted the fragility of today’s highly interdependent, concentrated global food systems (FAO 2022). Paradoxically, this fragility arises from the pursuit of efficiency. Short-term optimization of resources has tended to concentrate a large proportion of global production of many traded food commodities in locations with the most favorable cost/output ratios. This makes global supply of those commodities much more vulnerable to shocks in those locations than would be the case if there were less specialization and more redundancy in food systems, that is, if traded commodities were grown in more locations more widely dispersed around the globe. – Food Systems Economics, 2024
The pursuit of efficiency in food production has also increased greenhouse gas emissions due to the industrialisation of agrifood systems. This is largely due to the dependency on fossil fuels for fertilisers, herbicides, pesticides, fungicides, and the mostly diesel driven machinery needed to produce and package food. While the situation in the Gulf of Hormuz is not climate-related, the production facilities of agrichemicals and diesel in neighbouring states have been severely damaged.
The Gulf produces about 12% of worldwide nutrient production and roughly one-third of all globally traded nitrogen fertilizers. – CF Industries
It’s not just shipping that’s been disrupted. Qatar was forced to halt production at one of the world’s biggest urea plants last week, in the midst of what is planting season in much of the world. – World Economic Forum March 2026
Together with the 2026/2027 ’super’ El Niño‘, this is projected to result in catastrophic failures in global food systems.
Experts warn ‘very strong’ El Niño threatens to create perfect storm for food prices. Multiple crises have converged to threaten global food security, with experts warning of potentially catastrophic consequences for us all. – News.com.au 2026
Supply chains at risk
There are certain key foods consumed in large quantities that cannot be grown in New Zealand, or for which we do not produce enough to meet domestic needs. These at-risk commodities include sugar, wheat, maize, rice, and coffee, which are staples in the New Zealand diet or for livestock production and are not easily substitutable. Furthermore, these foods are imported from only a small number of places, so any disruption in trade flows or production in those countries will severely affect New Zealand’s food security. – Food Systems Economics, 2024
The Gulf produces about 12% of worldwide nutrient production and roughly one-third of all globally traded nitrogen fertilizers. –
Many of the world’s most important ports may be inoperable by 2050 due to even a modest rise in sea levels. Coastal inundation affects port operations even in non-coastal regions connected through land transport networks.
Similarly, shipping through the Panama Canal is already becoming problematic. The freshwater Gatún Lake in Panama is the main source of water for people as well as the operations of the lock system in the Panama Canal. As the climate warms, reduced wet-season rainfall is making the future of the canal uncertain.
Here in Aotearoa, even the transport between the North and South Islands is under threat, with both Wellington and Picton ports vulnerable to rising sea levels and aging infrastructure. Yet the coalition National-led Government crippled the Cook Straight ferry service by refusing to acknowledge this vulnerability, setting up this vital link to catastrophic failure (Fig. 6). This is particularly egregious as each island could provide food to the other when, not if, the next major climate event affects food crops. The result will be increased transport costs via other methods such as coastal shipping or flights.
Roading infrastructure is also at risk. For example, the Canterbury Climate Change Risk Assessment (V5.0) report calculated that 144km of roads within Ōtautahi/Christchurch City alone are currently exposed to surface flooding at 1% AEP, that is, a 1-in-100 year storm event, which are becoming more frequent. Moreover, this assessment was made prior to a 2023 GNS report, which found areas of Ōtautahi/Christchurch dropping (relative to the ocean) much faster than originally presumed. In some locations, the effects of rising sea levels will be felt as much as 80 years sooner than previously projected. That is, they are now at immediate risk.
Repairing roads and bridges will ultimately become unaffordable. This will likely result in some communities, particularly around Banks Peninsula where road access is already limited, becoming permanently isolated unless alternative transport routes (roads, ferries) are funded, developed, and maintained under the pressure of increasing weather extremes.
How did we get into this situation?
…fish in [warmer] waters will grow faster but will also mature to smaller sizes. Although this will help fish survive warming conditions, it will also decrease fisheries yields. – Editor, Science 2026 in reference to this research paper.
Persistently higher temperatures, heat waves and ocean warming have reduced livestock and fish stock yield and availability. Besides higher mortality among livestock and fisheries, heat stress results in lower egg production and weight. – Fulcrum 2024
Around 3 billion people depend on seafood for most of their protein. Invasive species and diseases are also migrating into new areas. And as permafrost melts, large quantities of the potent neurotoxin, mercury, is entering the food chain.
Increasing food-borne pathogens
Climate change is affecting the distribution and spread of food-borne pathogens, resulting in 600 million food-borne illnesses and 420,000 deaths annually. – Awad et al 2024
-
The thickness of the lines is proportional to the number of studies that mention the relationship between climate change and specific foodborne pathogens.
Isn’t more CO2 great for growing food?
This is often called the CO2 ‘fertilisation effect’. The speeding-up of photosynthesis—known as ‘CO2 fertilisation’—is well-known to be an important outcome of higher CO2 concentrations, along with increased water use efficiency. This is because as CO2 in the atmosphere increases, plants don’t lose as much water through their leaves because the number of their stoma decreases. So it might seem that drier conditions shouldn’t have such a large impact.
Five things wrong with this assumption:
2. Orchard crops (apples, pears, Kiwi fruits, avocadoes, grapes, cherries etc) can grow only within a certain optimal temperature range suited to each species. It can take several years for orchards to reach maturity. An orchard planted today may not survive a future climate by the time it reaches maturity. Or it may be less productive for fewer year and more prone to pests and diseases, making them too expensive to maintain.
_______________________________________________________________________________
3. Diseases thrive in a warming climate, and this includes plant diseases. An orchard crop may be productive for fewer year and more prone to pests and diseases, making them too expensive to maintain.
As we have seen, pathogens tend to migrate to follow suitable climates, as long as their hosts are present. This means that as humans respond to climate change with altered agricultural practice, crop diseases are likely to keep pace. – Dr Helen Fones 2020
4. Rapid plant growth is leading to increased warming and droughts: As the climate warms, warmer spring temperatures are also arriving earlier. In the Arctic and sub-Arctic, plant leaves are coming out sooner each year. This early ‘leaf-out’ is triggering an array of feedback effects including increased surface warming in the Northern Hemisphere Arctic:
We identify warming hotspots in the Canadian Arctic Archipelago (~0.7 °C), east and west edges of Siberia (~0.4 °C) and southeastern Tibetan Plateau (~0.3 °C). …With continued warming, positive feedbacks between climate and leaf phenology are likely to amplify warming in the northern high latitudes. – Xu et al, 2020
The Arctic is not alone in experiencing the not-so beneficial impacts of rapid springtime plant growth. Early and rapid spring growth across Europe in 2018 led to plants sucking up large quantities of water from the soil. By summer, the ‘legacy effect’ amplified summer drought conditions in areas that already were heat and/or water stressed.
Spring conditions led to an enhancement of photosynthesis early on in the growing season, but at the cost of strong soil-water depletion. In the crop-dominated areas in central Europe, increased growth in spring made ecosystems more vulnerable to drought in summer. – Dr Anna Bastos, 2020
The assumption that tropical forests across Africa and the Amazon will continue to absorb endless quantities of CO2 also has recently been brought into question. While forests that have not yet been burned for agriculture continue to grow larger and absorb CO2 :
Across Africa and the Amazon…higher temperatures and stronger drought conditions are slowing plant growth—and killing trees. – Hubai et al, 2020
_______________________________________________________________________________
5. The hotter it gets, the more CO2 plants release back into the atmosphere
Currently, around 25 per cent of carbon emissions from the use of fossil fuels is being taken up and stored by plants, which is good, as it helps reduce the concentration of greenhouse gases in the atmosphere.Our work suggests that this positive contribution of plants may decline in the future as they begin to respire more as the world warms. – Prof. Atkin, ANU
Photosynthesis peak at about 18C in many of the world’s leafy areas, then went into decline. However, respiration kept increasing, so plants were breathing out greenhouse gas faster, while taking progressively less in. With enough heat, they’d flip from sinks to sources. – Gibson, Stuff article on the above research
See also:
- 2025: The Guardian: Plants losing appetite for carbon dioxide amid effects of warming climate
- 2021: Ortiz-Bobea et al; Anthropogenic climate change has slowed global agricultural productivity growth, Nature Climate Change 11 pp 306-312
- 2020: Yale Climate Connections; More CO2 in the atmosphere hurts key plants and crops more than it helps:
- 2019: Yuan et al; Increased atmospheric vapor pressure deficit reduces global vegetation growth, Science Advances 5|8
COP28 Declaration on Food and Agriculture (2023)
In recognition of the relationship between climate change and both the existing and deepening issue of global food security, the UAE and the Bill & Melinda Gates Foundation launched a USD$200 million partnership for Food Systems, Agriculture Innovation, and Climate Action, focused on agricultural research, scaling agricultural innovations, and funding technical assistance for implementing the Declaration. The key points were:
- The UAE will join the CGIAR, a global partnership of international organizations engaged in research about food security, resilience, and climate adaptation.
- COP28 and a group of partners announced a collaborative effort to offer countries quality technical cooperation and to help deliver on the objectives of the Declaration. The partners behind the Technical Cooperation Collaborative pledged more than USD$200 million in new and newly aligned support, while also committing to increase coordination across their wider portfolios
- COP28 UAE, together with the World Business Council on Sustainable Development (WBCSD) and the Boston Consulting Group (BCG), supported by the UN Climate Change High-Level Champions, launched the Action Agenda on Regenerative Landscapes. This will see leading food and agriculture organizations join forces to scale regenerative agriculture, transitioning 160 million hectares to regenerative agriculture by 2030, accompanied by USD$2.2 billion in future investment, and engaging 3.6 million farmers worldwide.
- The High-Level Champions, in collaboration with non-government actors including farmers, Indigenous Peoples, consumers, cities, youth, businesses, financial institutions, philanthropies, and others, launched a Call to Action for Transforming Food Systems for People, Nature, and Climate, in support of the Declaration and to highlight the urgent need to take action on food systems by all actors.
Resource: Urban agriculture + community food organisations Aotearoa
Urban agriculture can nourish up to one billion city dwellers while supporting progress towards several other sustainable development goals. These range from strengthening livelihoods, extending environmentally sustainable production and creating new local food supply chains to enhancing ecosystem services such as climate change adaptation and countering the urban heat island effect. Urban agriculture can also play a major role in strengthening the resilience of cities and communities. – The Economics of the Food System Transformation 2024
More information
Home > Climate wiki > Impacts >