The true impact of food waste, explained

 by Nathalia Anne A. Martinez

Photo by Gareth Willey on Pexels

Because food is so plentiful, it is often taken for granted. People are unaware of the tremendous amount that is wasted and its associated impacts, as well as its link to climate change. According to the seminal work of the UN Food and Agriculture Organization (FAO), food waste exacerbates the climate crisis with its significant carbon footprint. Recent estimates suggest that food waste contributes to about 10 percent of total anthropogenic greenhouse gas (GHG) emissions.

“A carbon footprint measures the total GHG emissions caused directly and indirectly by a person, organization, event, or product” (The Carbon Trust, 2018). Carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) are GHGs, all of which have varying potentials to trap heat in the atmosphere. In essence, the sum of all GHG emissions is what we consider a carbon footprint, expressed in carbon dioxide equivalents or CO2 eq (FAO, 2015).

Why does carbon footprint matter to societies?

The carbon footprint is actually a component of the ecological footprint, a comprehensive metric that “measures how fast we consume resources and generate waste compared to how fast nature can absorb our waste and generate new resources” (Global Footprint Network, n.d.a). The truth of the matter is that earth’s resources are rapidly depleting due to overconsumption. “Ecological overshoot occurs when humanity’s demand on nature exceeds what ecosystems can supply” (The World Counts, n.d.).

Today, we are using the resources of about 1.7 earths yet we only have one.

What can we do? The Global Footprint Network (n.d.b) underscores the importance of reducing humanity’s carbon footprint to end overshoot and start living within our planet’s means.

It goes without saying that transportation is a major contributor to GHG emissions due to the burning of fossil fuels. Unbeknown to most of us, global food waste contributes just as much to GHG emissions. How? Let us take a closer look at food waste and its carbon footprint.

Source: Our World in Data

From farm to fork

A large portion of the food produced for human consumption never makes it to our plates. Food loss and waste occur at every stage of the supply chain for a variety of reasons. Notably, there is a distinction between ‘food loss’ and ‘food waste.’

Food loss refers to produce that is lost unintentionally due to “market conditions, poor infrastructure, poor agricultural practices, pests, disease, natural disasters, and weather events” (World Wildlife Fund [WWF], 2021). Food waste, on the other hand, is often a result of negligence or a deliberate decision to discard food, particularly at the retail or consumer levels (WWF, 2021).

In the commonly cited 2015 report of the UN FAO, about one-third of global food production is wasted. Throwing away food may appear to cause minor environmental damage, but the consequences are far more serious than we realize. In fact, estimates suggest that food waste accounts for 8 to 10 percent of total anthropogenic GHG emissions (UNEP, 2021). This is almost equivalent to the contribution of global road transport emissions (FAO, 2015).

How is carbon footprint measured? This chart by Our World in Data illustrates the carbon footprint of 29 different food products. GHG emissions resulting from each stage of the supply chain—from land use change to packaging and everything in between—make up a food’s carbon footprint.

“Products hold different carbon footprint intensities” (FAO, 2015). Overall, plant-based foods have much lower carbon footprints than animal-based foods. Meat products, especially beef, have higher carbon footprints due to GHG emissions from land use change, high-intensity farming, and manure management, among other things.

The farm, retail, food service, and household levels account for the majority of food loss and waste. There are complexities, however, in measuring food waste in different segments of the supply chain, most especially the farm stage (WWF, 2021). According to the Food Waste Index Report 2021 by the UN Environment Programme (UNEP), “Global estimates of food waste have relied on extrapolation of data from a small number of countries, often using old data.”

Break it down

Most people believe that it is okay to simply dump food scraps into landfills or leave them outdoors because after all, they are biodegradable. The truth is: “Food scraps don’t decompose as fast as you think,” says McDarris (2021). 

“Biodegradation is the process by which organic substances are broken down by enzymes produced by living organisms” (Science World, n.d.). Certain environmental conditions are necessary for food to decompose quickly. These include the availability of air, warm temperatures, availability of water, and chemical composition of food (higher nitrogen to carbon ratio).

Landfills, however, do not provide such conditions, making it difficult for food waste to break down. When food is left to rot under anaerobic (in the absence of oxygen) conditions, it releases methane which is several times more potent than CO2 at trapping heat in the atmosphere, impacting climate change. 

Image by melGreenFR from Pixabay

Composting, an otherwise aerobic process, diverts methane-generating food waste from landfills and stockpiles. The ideal conditions offered by proper composting bring about optimal biodegradation. “In the presence of oxygen and water, microbes, such as bacteria and fungi, use the carbon for energy and decompose the organic wastes” (Brooksbank, 2021).

WATCH: Why is Composting Good for the Environment? 

“When you do aerobic activities to the food waste, it helps prevent the methane from being released into the atmosphere. It’s very much different from when you just leave the food waste in the landfill. That’s what you call the anaerobic way of handling food waste. When there is anaerobic decomposition, that is when the methane is released into the atmosphere,” explains Maria Buena Victoria Tenefrancia, an environmental advocate and President of Zero Waste Baguio.

Below the radar

Sadly, the link between food waste and climate change is not well-recognized in the Philippines. The COVID-19 pandemic further exposed gaps in how the country handles food loss and waste.

According to the Food Waste Index Report 2021, the Philippines generates over 9 million tonnes of household food waste per year, but there is very low confidence in this estimate due to the lack of available and reliable data.

“First of all, people are not yet aware that a lot of food is being wasted. And more so, they are not aware that it is so much connected to climate change. We still need to educate and make people aware that if we do not properly manage our food waste, it will have a bearing on climate change. It’s not just a drop in the bucket,” Tenefrancia says.

Essentially, reducing food waste can curb GHG emissions, contributing to climate change mitigation. One of the Sustainable Development Goals (SDGs) is to ensure sustainable consumption and production patterns. Specifically, SDG target 12.3 aims at “[halving] per capita global food waste at the retail and consumer levels and reduce food losses along production and supply chains, including post-harvest losses.”

Practicing conscious consumption minimizes one’s impact on the environment. Composting is an environmentally friendly way of handling food waste. Additionally, Tenefrancia stresses the importance of funding research and development to find strategies to reduce food loss and waste throughout the supply chain.

Tenefrancia puts it simply: “If you lessen your food waste, then there’s lesser methane that will be released into the atmosphere which adds up to climate change.” By being cognizant of the carbon footprint of food waste, we can learn to minimize ours.


Brooksbank, K. (2021, October 15). Composting to avoid methane production. Government of Western Australia. 

Food and Agriculture Organization of the United Nations. (2015). Food wastage footprint & climate change. 

Global Footprint Network. (n.d.a). Ecological footprint. 

Global Footprint Network. (n.d.b). Climate change. 

McDarris, A. (2021, January 14). Once you know what happens to food you leave outdoors, you’ll stop doing it. PopSci+.’t%20decompose%20as%20fast%20as%20you%20think&text=But%20fewer%20people%20are%20aware,don’t%20exist%20in%20nature.  

Ritchie, H. (2020, January 24). You want to reduce the carbon footprint of your food? Focus on what you eat, not whether your food is local. Our World in Data. 

Science World. (n.d.). Rotting. 

The Carbon Trust. (2018). Carbon footprinting guide.

The World Counts. (n.d.). We are consuming the future. 

United Nations. (n.d.). Goal 12: Ensure sustainable consumption and production patterns. 

United Nations Environment Programme. (2021). Food waste index report 2021. 

World Wildlife Fund. (2021). Driven to waste: The global impact of food loss and waste on farms.