Food systems account for roughly one third of global greenhouse gas emissions. Food loss and waste on their own make up 8 to 10 percent of total emissions. According to the Food Waste Index of the United Nations Environment Programme (UNEP), 1.05 billion tonnes of food were wasted in 2022. Over the same period, around 733 million people were facing hunger. Taken together, these figures move waste beyond a technical question of efficiency and make it a critical component of both climate change and global food security. Preventing food loss and waste has therefore become a dimension of climate diplomacy that can no longer be left aside.
The Link Between Climate Change and Food Security
The relationship between climate change and food security has to be examined step by step, from farm to fork, and at the same time as a whole. Before assessing how climate change affects food security, it is therefore useful to set out what food security means and which dimensions it rests on.
Food security: a situation in which all people, at all times, have physical, social and economic access to sufficient, safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life.
The dimensions of food security: availability, access, utilization and stability.
These four dimensions make it easier to analyse food systems across the whole process that runs from farm to fork. Climate change affects all four, but its most direct effect is on food production. Production is one of the critical components of food systems, which also cover processing, packaging, transport and waste management. Food loss occupies an important place in the process through which these systems bring food to the consumer. It has been noted, for example, that the food that is lost and wasted could feed 1.2 billion people.
In terms of availability, food production is affected by climate change in a number of ways. Rising temperatures, irregular rainfall, drought, floods and heatwaves, together with sudden and destructive weather events, all have a direct effect on productivity in food production.
The access dimension covers the economic and physical capacity of households to obtain food, and is shaped by income, prices, infrastructure and the way markets function. The supply contraction that climate change causes in production pushes food prices up, and these price increases hit low income households disproportionately, since they spend a large share of their income on food. Climate change also works through the income side. For small scale producers, losing a crop means losing a source of food and the only source of income at the same time. This deepens rural poverty and pushes households towards distress sales of assets. Climate shocks therefore affect the access dimension indirectly but severely.
The utilization dimension covers how far the nutritional value of the food consumed can be used by the body, which brings in diet quality, food safety, access to clean water and health conditions. Rising CO₂ concentrations in the atmosphere lower the protein, zinc and iron content of staple crops such as wheat, rice and legumes, and make the micronutrient deficiency known as hidden hunger more widespread. Projections for the middle of the century suggest that this mechanism could leave hundreds of millions of additional people at risk of protein and zinc deficiency.
The stability dimension refers to keeping availability, access and utilization in place without interruption over time. Even if a person has access to enough food in a given period, food insecurity is still present if that access is fragile in the face of climate shocks. It is precisely in this continuity over time that climate change does the most damage. As extreme weather events such as drought, floods, heatwaves and irregular rainfall patterns become more frequent and more severe, agricultural output swings unpredictably from year to year and harvest losses turn into sudden supply shocks. These shocks do not stay at the level of production. Through global value chains they turn into price volatility and carry instability to the international level. Instability also reproduces vulnerability, because it pushes households towards coping strategies such as selling assets and cutting consumption, which leave them permanently poorer. Climate change turns the stability dimension into an area of chronic risk. Early warning systems, strategic food reserves, climate resilient agricultural practices and rules based trade mechanisms stand out as the policy tools that can protect supply and price stability. Without them, the risk grows that temporary shocks develop into structural food insecurity.
The Link Between Food Waste and Climate Change
Food waste is both a major driver of climate change and an increasingly visible result of it. According to UNEP data, around 1.05 billion tonnes of food were wasted in 2022, and roughly 19 percent of the food available to consumers was thrown away at household, food service and retail level. Once the 13 percent of food lost in the supply chain between harvest and retail is added, it becomes clear that around one third of the food produced is never consumed.
The Intergovernmental Panel on Climate Change (IPCC) estimates that food loss and waste are responsible for 8 to 10 percent of global anthropogenic greenhouse gas emissions. If food waste were a country, that share would make it the third largest source of emissions in the world after China and the United States. These emissions come from three main sources. The first is the emissions produced while the wasted food is being grown. Land use change, fertilizer use, methane from livestock, energy use and transport all feed into this first source. The second is the methane released as organic waste sent to landfill breaks down. Over a hundred year timescale, methane is roughly 28 times more powerful as a greenhouse gas than carbon dioxide. The third is the indirect resource cost of waste. According to the FAO, wasted food ties up around 28 percent of the world’s agricultural land as well as a significant volume of freshwater. Once losses at farm level are included, the total climate burden is estimated to be higher still.
At the same time, the drought, extreme heat, floods and shifting rainfall patterns brought by climate change increase harvest losses and raise the risk of spoilage in regions with weak cold chain infrastructure, which deepens food loss further. The result is a self reinforcing cycle. Waste raises emissions, higher emissions make climate shocks more severe, and those shocks lead to new losses.
Preventing Food Waste and Global Food Security as a Critical Component of Climate Diplomacy
Breaking this self reinforcing cycle and strengthening climate action requires climate diplomacy to be used effectively. For a long time, climate diplomacy kept food systems at the edge of the agenda. Agricultural issues were only taken up formally with the Koronivia Joint Work on Agriculture. The real turning point came at COP28 with the Declaration on Sustainable Agriculture, Resilient Food Systems and Climate Action, signed by more than 150 countries. Even so, the implementation gap is clear. As of 2022, only 21 countries had added a food loss and waste reduction target to their Nationally Determined Contributions. This shows that the commitment under Sustainable Development Goal 12 to halve per capita food waste by 2030 has not been tied closely enough to the climate change regime.
Reducing food waste is also vital for the success of climate diplomacy. Consistent and sustained measurement, combined with public and private sector cooperation, makes considerable progress possible in cutting food loss and waste. OECD data show that a large part of current agricultural support mechanisms remains out of line with climate and productivity goals, and that restructuring this support would deliver gains both in lowering emissions and in improving access to food.
The methodology of the UNEP Food Waste Index can serve as the basis for national measurement systems. Progress could then be tracked, and international commitments could gain credibility. As the 2024 UNEP report stresses, public and private partnerships are among the most effective instruments for reducing waste at retail, food service and household level. Spreading this model through the G20 and regional organizations matters for the success of climate diplomacy.
Conclusion
Food waste sits at the point where the climate change and food security agendas meet, and it is an exceptional policy instrument that serves both goals at once. Its strength comes from the two sided nature of the problem. Every meal that is wasted means that the greenhouse gases released during its production were released for nothing, and it also means the loss of food for someone, somewhere, who is facing food insecurity. Action to prevent food waste therefore produces positive results both in cutting emissions and in securing access to food. Preventing food waste is in this sense an important and measurable variable in the fight against climate change. Framing the issue in this way turns it into a legitimate item for negotiation in climate diplomacy.
This awareness needs to be translated into concrete mechanisms. COP28 was the first major threshold that brought food systems to the centre of the climate agenda, and with the United Arab Emirates Declaration the relationship between climate and food systems, covering production, consumption, food waste and food loss, entered formal negotiating language. Whether this opening becomes a lasting gain depends on three conditions. The first is common measurement standards. As long as food waste cannot be measured in a comparable and verifiable way, monitoring commitments will remain difficult. The second is financial flows. Measurement infrastructure, cold chain and logistics improvements require resources, and those resources need to be treated explicitly as a subheading of climate finance. The third is writing these elements into Nationally Determined Contributions (NDCs) as binding targets, because only a commitment recorded in an NDC comes under the enforcement power of the international review cycle.
These three conditions feed one another in sequence. Without measurement, it stays unclear where finance should be directed. Without finance, NDC targets remain on paper. A target that is not written into an NDC lacks the political pressure needed to drive measurement and finance. The three should therefore be analysed and applied together as one connected set of conditions rather than separately.
The political momentum created by COP28 is still recent, and the NDC updating cycle offers a rare technical opening for waste targets to be built into national commitments. Once that cycle closes, the targets will be put off to the next round and valuable years will be lost.
Analytically, the conclusion is clear. Preventing food waste, as a critical component of climate diplomacy, is a low cost and high return form of climate action. The technical solutions are largely available; what is missing is institutional commitment. Missing this opportunity would push back the 2030 horizon not for one goal alone but for two connected goals, emission reduction and access to food. Food waste should therefore be positioned not as a secondary heading that can be postponed, but as one of the priority and time sensitive instruments of the 2030 agenda.
