Waste not: A breakthrough for climate and food security
This post is written by Clementine O'Conner, United Nations Environment Programme, and Richard Swannell, Oxford Martin School Visiting Fellow
Reducing food loss and waste is one of the most practical and cost-effective actions we can take to address climate change, while also strengthening global food security. Food loss and waste exposes how our largely linear food systems continue to undervalue food as a resource that should be conserved, reused and returned to productive use; a flaw in their design. As London Climate Action Week brings together leaders from across sectors to accelerate solutions, this issue demands far greater attention and action.
The scale of the challenge is staggering. Around 19% of food available to consumers is wasted at retail, food service and household levels. In addition, an estimated 13% of the world's food is lost in the supply chain after harvest and before reaching markets. Together, these losses impose an enormous economic burden, costing the global economy more than a trillion dollars each year while placing unnecessary pressure on land, water, and energy resources.
The environmental consequences are equally significant. Food loss and waste account for an estimated 8-10% of global greenhouse gas emissions. When food ends up in landfill, it decomposes and releases methane, a greenhouse gas that is 86 times more potent than carbon dioxide over a 20-year period. Reducing food loss and waste therefore offers an opportunity to achieve rapid climate benefits at a time when every fraction of a degree matters.
Yet the food security dimension may be the most compelling of all. Around 733 million people worldwide experience hunger, even as vast quantities of edible food are discarded every day. In an increasingly uncertain world marked by geopolitical tensions, supply chain disruptions, economic instability and climate impacts, assuring food security has become a priority for countries across the globe. Reducing food loss and waste is not only about cutting emissions or waste streams, it is also about making better use of existing resources, including recovering nutrients, feed, and energy from food that would otherwise be lost. Action on food loss and waste is not simply an environmental imperative; it is a strategic necessity.
Encouragingly, progress is possible. Japan has halved food waste per capita, while the Netherlands, United Kingdom and Republic of Korea have achieved significant reductions through targeted politics and partnerships. The European Union's mandatory reduction targets are also sending clear signals to governments and businesses. These examples show that progress depends on systems change and behaviour change working together.
We already know what works: better measurement, clearer policies, improved supply chains, education, redistribution and circular solutions. The challenge is scaling these approaches quickly and effectively.
Prevention must come first. But where waste cannot be avoided, solutions such as composting can recover nutrients and improve soil health, contributing to more resilient food systems while cutting emissions and costs.
Global initiatives are helping to accelerate action. The United Nations Environment Programme's Food Waste Breakthrough is supporting cities and businesses through data, policy and finance, while Food Pacts led by WRAP, WWF and partners are driving collaboration across supply chains. Together, these efforts are turning ambition into implementation.
The message from London Climate Action Week is clear: reducing food loss and waste is a climate solution, a food security solution and an economic opportunity. In a resource-constrained world, it is also a way to build resilient through more efficient, circular use of what we already produce. The question is no longer whether we know what to do, it is whether we will act with urgency.