But in the first global assessment of its kind, a new Nature Food study has made a surprising discovery: tackling food loss and waste globally would actually drive what’s called a ‘rebound effect’, where people end up buying more food. That could unravel up to two-thirds of the projected environmental benefit of avoiding loss and waste in the first place—an “unanticipated trade-off,” cautions the study’s lead author Margaret Hegwood.
Initially, it seems like a no-brainer that tackling the one-third of all food lost annually during production and transport, and wasted in our homes, would erase its environmental impacts: food loss and waste accounts for 24% of the food sector’s emissions, and 6% of the global total. But the new study shows that erasing this impact isn’t a given, if you go a step further to investigate how such changes influence consumer behavior.
The study looked at steps to reduce food loss and waste laid out by the United Nations Sustainable Development Goals, then combined this in a model with data from previous research, to understand how markets respond to the increases in food supply that would result from these actions to alleviate loss and waste.
Previous studies had explored this at the regional and national level before, but the new study is the first to take a global perspective on this dynamic—and what it found was striking. As food supply goes up with avoided loss and waste, the researchers’ model showed that markets typically respond by decreasing food prices, which increases consumers’ purchasing power. In turn, this leads them to buy more food than they ordinarily would have done.
This so-called ‘rebound effect’ is a phenomenon most studied in energy markets, where research shows that greater energy efficiency creates savings that actually lead to more energy use, not less. This offsets the original environmental benefit of that greater efficiency. When it comes to food, the study found that this rebound effect is powerful enough that if food loss and waste were completely eradicated, the resulting increase in food availability and the following surge in food purchases would offset between 53% and 71% of emissions avoided from the originally averted loss and waste.
The reason this emissions surge happens comes down to how consumer buying behavior influences practices in the field. “Prior to our study, the rationale was that reducing food loss and waste would result in less food production, and consequently lessened environmental impacts,” says Hegwood, who is a PhD candidate at the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder. Hegwood explains the thinking was that farmers would have to produce one-third more food than necessary to plug the gaping hole created by food loss and waste. And that without the need for that extra production, all the associated resources—land use, fertilizer, water—would therefore be saved.
“In contrast, our study proposes that rebound effects—i.e. increased consumption due to lower food prices—could decrease production less than anticipated,” Hegwood explains. With more production than expected, the expected environmental impacts go up, too.
These findings are perhaps disappointing to many who believed that tackling food loss and waste was a sure route to lower emissions. Even so, this doesn’t mean we should stop trying to reduce food loss and waste—the opposite in fact, as it still could bring several benefits, the study says.
Firstly, increased purchases didn’t totally eclipse all the environmental gains: there were still some avoided emissions to be achieved by cutting food loss and waste. But more importantly the study authors find that cheaper, more available food could lead to big benefits for food security. Rebound effects would increase calorie, fat, and protein consumption in most low-income regions of the world. Notably in sub-Saharan Africa more food at cheaper prices would increase the availability of calories by 320 per person, per day—which makes up 16% of the daily calorie intake that’s recommended for a healthy diet.
These benefits shouldn’t be overlooked, and should be uppermost in policymakers’ minds when devising food waste reduction efforts. “I hope that our research adds nuance to the discussion,” Hegwood says. “Previously, reducing food loss and waste was seen as a widespread “win-win”, but our results invite policy makers to consider important tradeoffs between environmental and food security impacts.”
Hegwood, et. al. “Rebound effects could offset more than half of avoided food loss and waste.” Nature Food. 2023.
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