The environmental evaluation of food waste prevention is considered a challenging task due to the globalised nature of the food supply chain and the limitations of existing evaluation tools. The most significant of these is the rebound effect: the associated environmental burdens of substitutive consumption that arises as a result of economic savings made from food waste prevention.
The take-home-messages from our research are that:
Food waste in the UK has a large carbon footprint, but that reducing these impacts is not as simple as just reducing food waste. Our analysis improves on previous work by including the "rebound effect". Additional activities by households as a result of savings made due to food waste prevention has an environmental impact, and when you include this effect, it reduces the greenhouse gas (GHG) benefits of avoiding food waste by up to 60%.
Our analysis is also novel because it takes into account greenhouse gas emissions from across the international supply chain (ie, including food imports). We find that while 44.4% of UK spending on food occurs abroad (ie for imported products), these imports are responsible for 77.4% of the UK's food-related GHG emissions. ie. food wasted in the UK has a big GHG footprint, in large part because a lot of it comes from overseas where agriculture is less-efficient, and so has a larger GHG footprint.
The conclusions are that:
food waste has a large GHG footprint,
It's not enough to just target reductions in food waste - we really need economy-wide reductions in GHG emissions, so that rebound spending doesn't undermine the effect of behavioural interventions (such as WRAP's "love food, hate waste" campaign); and
There are also opportunities to reduce the UK's food footprint by increasing agricultural efficiency in the developing world, where much of our food imports originate.