How many tons of food are wasted worldwide each year?

How to get close to this number

Take a share of production. The world produces a few billion tonnes of food a year, and the explanation gives waste as roughly a fifth of everything available to consumers. A fifth of a few billion gives a figure around a billion tonnes.

The distribution is the part that surprises: households throw away the largest share, ahead of restaurants and shops. Public attention focuses on supermarkets discarding stock, but the biggest single point of loss is domestic kitchens — which means the intervention that matters most is the hardest one to legislate.

The emissions comparison in the explanation is the one that reframes it entirely: if food waste were a country it would be the third-biggest emitter of greenhouse gases. Wasted food carries the full climate cost of having been grown, transported and refrigerated, and then adds methane as it decomposes. It is the largest climate intervention available that requires no new technology at all.