A new study cited by FoodNavigator suggests that food waste - a significant portion of which comes from people not consuming what they buy - is a bigger problem than previously thought, and reducing it by half could help eliminate approximately a quarter of the total greenhouse gas emissions from the global food system.

One-third of food is wasted

It is already a familiar statistic that approximately one-third of all food produced is lost or wasted each year. So much so that if food waste were a country, it would be the third-largest emitter of harmful greenhouse gases into the atmosphere as it decomposes in landfills, following the United States and China.

It is also often reported that the global food system accounts for about a quarter to a third of global greenhouse gas emissions. Now, here's a new number: approximately half of these emissions from food systems come from food loss and waste. Furthermore, over one-third of the emissions generated by food waste come from the food discarded by consumers.

Why is this important? It suggests that simple steps by individuals to prevent food loss and waste in their homes would significantly contribute to reducing the negative impact that the food system has on the environment.

A recent study published in Nature Food analyzed 54 food products and 164 countries and regions. It estimated that global emissions from food waste in 2017 totaled 9.3 billion metric tons of CO2 equivalent - more than double previous estimates.

Food waste consists of both food losses (occurring in production, storage, processing, and transportation phases) and food waste (discarded by consumers, retailers, or food service providers).

That being said, food discarded by consumers accounted for approximately 35.5% of the total emissions from food waste, according to the study. These emissions were higher than the food discarded by wholesalers, retailers, and traders, which accounted for about 11% of the total, with the remainder coming from other stages of the food production.

A global issue

Food waste by consumers is a larger problem in the United States and China. According to the study, one-third of the emissions caused by consumer food waste in China and the US are comparable to the greenhouse gas emissions generated by all stages of global food processing and transportation. Meanwhile, four non-European countries - Brazil, China, India, and the US - are responsible for about 40% of all emissions from food waste, the research added.

But European consumers are not without blame, and food waste by consumers is a problem throughout the wealthy Western world. Nearly half of UK parents, for example, admit to throwing away food that is still edible or can be safely consumed, according to recent research by cream biscuit maker Jacobs.

The main reasons cited include:

• Packages being opened for too long
• Too much food purchased during shopping
• People not knowing what to do with leftover food

Nearly half of the respondents said they regularly throw away leftovers from previous meals. Over one-third struggle to consume all the fresh fruits and vegetables they buy.

Other research has warned that the issue of food waste will worsen as emerging countries such as China and India continue to adopt Western dietary lifestyles.

GDP and Education

The authors of the Nature Food study noted that food losses (related to production, storage, processing, and transportation phases) are lower in countries with higher per capita gross domestic product due to the availability of advanced and environmentally friendly waste treatment technologies.

High-income countries should focus on reducing food waste and promoting plant-based diets (more on this point later), they said. In contrast, low-income countries could prioritize avoiding food losses in production and implementing appropriate waste treatment using suitable technologies.

So, how much lower would global emissions from the food system be if food waste caused by consumers were significantly reduced? Indeed, Ke Yin, a researcher at Nanjing Forestry University and one of the study's authors, told FoodNavigator, "It would be much lower."

To reduce food losses and waste at the consumption stage, the study's authors wrote that "supporting rational food consumption behaviors and advanced technologies can both be helpful."

What exactly do they mean by "rational"? "In our view, 'rational' means that when people consume food, they are aware of the environmental cost of food products from production to the shelf and the environmental issues caused by food loss and waste, and they weigh their own situation, including the quantity of food, the food they consume, the budget, and the time limitation," Yin told us. "We encourage people not to hoard and not to consume excessive amounts of food."

The easiest battle to win

Yin and his researchers recommend intervention strategies that include halving meat consumption and implementing technological advancements to reduce emissions, such as composting and anaerobic digestion. These interventions could halve food waste and reduce greenhouse gas emissions by about a quarter.

(References: Cradle-to-grave emissions from food loss and waste represent half of total greenhouse gas emissions from food systems Nature Food​ https://doi.org/10.1038/s43016-023-00710-3 Food Surplus and Its Climate Burdens The Potsdam Institute for Climate Impact Research​ 10.1021/acs.est.5b05088)