Whether it is because you cooked too much for, let it go out of date or your kid didn’t fancy it, it just doesn’t feel right. Not only is it an awful waste but it can really add to your carbon footprint.
In this post we are going to tuck in to the numbers of the food we waste, lose and eat. In doing so we will see just how big the carbon footprint of food waste is.
What is the scale of food waste?
How much food a person wastes varies greatly depending on what their income is, how they eat and where they live.
On average each person on the earth wastes around 50 kg of edible food every year. But as you can imagine, the food wasted by a wealthy suburbanite varies greatly from someone living in poverty.
The following chart is an estimate of per person food waste for seven different regions of the globe, and is based on the 2011 FAO report, Global Food Losses and Food Waste.
The contrast between the levels of food waste in different regions of the world is stark.
In Sub-Saharan Africa consumer food waste per person is less than 10 kg a year. This rises to 25 kg per person in Latin America and reaches almost 80 kg in the most industrialized parts of Asia: China, Japan and Korea. For the United States, Canada, Australia and New Zealand the average is about 110 kg, more than 10 times that of poor regions.
In a world where 850 million people are undernourished (FAO 2012), more than 350 million tonnes of good food is wasted each year. That’s about 10% of total food supply.
On top of the food that is wasted at household level, more than double this amount again is lost in different food production phases.
The importance of production losses
In addition to food wasted by consumers an enormous volume of food is lost during production. These losses occur in different stages of the supply chain including harvest, storage, handling, transportation, processing, distribution and retail.
The volume of edible food lost in all of these production stages is about 940 million tonnes each year. That equates to around 140 kg per person or 25% of total food supply, and highlights some of the inefficiencies in the global food supply.
Using data from the same report we can see the scale of both consumer waste and production losses as a share of total food supply in different food groups.
Almost half the Roots & Tubers (potato, cassava and sweet potato) and Fruit & Vegetables produced globally are not consumed, while for Fish and Cereals it is roughly a third.
In wealthy regions, like North America and Europe, consumer waste typically accounts for more than 15% of the total supply of Fruit & Vegetables, Cereals, Fish, Dairy and Roots & Tubers.
In developing regions consumer waste tends to be much smaller, so losses are dominated by production phases such as harvesting, storage and handling. Production losses are particularly large for perishable foods in warm climates and for crops that produce seasonal gluts.
What the world loses, wastes and eats
Global food production can be split into three main categories: production losses, consumer waste and consumption (food that is eaten).
If you split food supply into different food groups and divide by population you can estimate what the average person on earth consumes, loses and wastes.
Global food supply per person is around 580 kg. Of this roughly 380 kg is consumed, 140 kg is lost in production and 50 kg is wasted by consumers. Of the 50 kg of food wasted per person, around half comes from cereals and a further quarter from fruit and vegetables.
Using these figures we can understand the climate impact of food waste, losses and consumption at a global level.
The carbon footprint of food waste
To work out the carbon footprint of food waste you need to consider all the emissions within the food system. These emissions can be broken down into four main areas.
- Agriculture: soil management, enteric fermentation and other sources
- Pre-production: energy use in fertilizer, pesticide and feed production
- Post-production: refrigeration, processing, packaging and distribution
- Deforestation: indirect emissions from converting forest to farmland
Using estimates from Vermeulen et al (2012) for each of these sectors, and knowing that total food production is around 3.8 billion tonnes each year, we can get a very rough idea of the food waste emissions per person in each region.
In this graph the consumer waste footprint grows from about 25 kg CO2e in Sub-Saharan Africa to more than 350 kg CO2e for the USA group, while the global average is 170 kg CO2e. But these ‘estimates’ are really just a rough starting point, because they assume we all eat the same type of food, produced in the same way, with equal deforestation impact. None of which are true.
In real life our food waste footprints are much more complicated.
In wealthy countries like the USA, Canada, Australia and Europe food waste often includes a greater share of carbon intensive foods. These could be foods with far higher agricultural emissions like red meat and dairy products, or those with high post-production emissions like ready meals and processed foods. This reality is borne out by national studies for the US (Venkat) and the UK (Chapagain), which estimate food waste emissions to be 300-400 kg CO2e per person not including deforestation emissions.
Attributing deforestation emissions to the food chain, while important, is extremely troublesome. So much so that they are normally handled separately as part of land use emissions. The majority of deforestation emissions occur in South America (Brazil) and South East Asia (Indonesia). These are largely driven by clearing forests for soy, beef and palm oil production. Because the sale of palm oil, soy (also as feed) and beef is so commoditized it is very difficult to understand the role of your food plays in these emissions.
On top of waste emissions it is worth stressing that for every 100 kilograms of food we waste, a further 50 kg of production losses occur. In other words for every extra two kilograms of food we waste a further kilogram is lost during production, further adding to climate impact of food waste.
The big footprint of food waste
Food emissions are a big deal.
If you include deforestation emissions, together with agriculture and production emissions, the food chain accounts for roughly 12.5 GtCO2e, or a quarter of total global man made carbon emissions. Consumer waste is responsible for around 10% of this, and production losses account for a further 25%.
In wealthy countries people waste around 100 kg of edible food a year. This food waste has a footprint of 300-400 kg CO2e, not including the additional impacts of deforestation and further production losses.
If you want to shrink your food footprint, then reducing your food waste is a great place to start. This is a topic we will return to.