The energy loss

By throwing away food, we are not only wasting the actual produce but also the resources and energy within it.

Food systems consume about 30% of available global energy and out of this, 38% is utilised to produce food that is either lost or wasted (FAO, 2015). Producing food emits CO2 into the atmosphere, as we continue to burn fossil fuels and cut down forests. Additionally, methane is emitted due to an increasing demand in meat and the use of landfill, while nitrogen dioxide is emitted from fertilisers, and hydrofluorocarbons are emitted from produce refrigeration. 

Hard to believe?

  • Growing the 133 billion pounds of food that retailers and consumers discard in the US annually slurps the equivalent of more than 70 times the amount of oil lost in the Gulf of Mexico’s Deepwater Horizon disaster: 3.19 million barrels of oil (Bloom, 2011)
  • The energy used to produce the 24.4 billion pounds of dairy products the US throw away in a year could meet the entire world’s energy needs for one day (Cuellar & Webber, 2010)
  • Agriculture, Forestry, and other Land Use (AFOLU) is responsible for just under a quarter (~10–12 GtCO2eq/yr) of all anthropogenic GHG emissions mainly due to deforestation and agricultural emissions from livestock, soil and nutrient management (Smith et al. & IPCC, 2014)

Within food production, what do we actually need energy for?

Globally, the agrifood chain consumes 30% of the world’s available energy with more than 70% consumed beyond the farm gate (FAO, 2018; Gao et al., 2017; Vermeulen et al., 2012)

Modern agriculture requires an energy input at all stages of agricultural production, whether directly or indirectly:

  1. Direct energy: irrigation, harvesting and cultivation, processing, storage and transportation
  2. Indirect energy: refers to the energy required to manufacture inputs such as machinery, equipment, mineral fertilizers and chemical pesticides (herbicides and insecticides)

Where do we get this energy from and what’s the issue with these energy sources?

Non-renewable energy sources also known as fossil fuels are coal, oil, and natural gas. By burning or releasing these fuels, greenhouse gases (GHGs) are produced that impact the Earth's natural systems. Additionally, drilling and mining for fossil fuels present short-and longterm environmental impacts (UCS, 2019; NRDC, 2018).

Sunlight passes through the atmosphere and heats the Earth’s surface before it is radiated back into space (NASA, 2019). GHGs in the atmosphere naturally trap some of that heat before it escapes back. This is called the greenhouse effect and its what makes Earth liveable.

However, human activity, particularly through the burning of fossil fuels, has lead to an increased release of GHGs into the atmosphere (NASA, 2013; NRDC, 2018), thickening that blanket and trapping excess heat. The result is a warming planet, in which the temperature is likely to increase by 1.5°C between 2030 and 2052 at the current rate (IPCC, 2018; Bloomberg, 2015).

How is food waste contributing to this problem?

More than 70 billion tons of GHGs could be prevented from being released into the atmosphere, if we cut down on food waste (Frischmann, 2018). If today’s food system remains unchanged and global agriculture is forced to increase production by 70% to satisfy predicted demand, then GHG emissions will grow by 30% (FAO, 2014)

Food waste accounts for about 8% of total global GHG emissions, equating to 3.3 gigatons of CO2 equivalent (FAO, 2013) or 4.4 gigatons of CO2 equivalent with land use change included (FAO, 2015). This means that the contribution of food waste emissions is almost equivalent to global road transportation (IPCC, 2014) and makes food waste, if it were a country, the third largest emitter in the world (FAO, 2015).

Carbon dioxide emissions

  • GHG emissions are often calculated in terms of CO2 equivalents (WWF, p.12, 2012)
  • A single ton of organic waste generates 4.2 tons of CO2 (Power Knot, 2012)
  • CO2 is emitted into atmosphere as fossil fuels are burned to produce electricity to power facilities and fuel transportation modes needed within the food system (Sonesson et al., 2009)
  • A food product's carbon footprint is the total amount of GHGs emitted throughout its entire lifecycle. Products have different lifecycles and therefore differing carbon intensities. Meat and cereals are 'climate hotspot commodities'  as they have the largest environmental impact of all produce (Notarnicola et al., 2017; FAO, 2015)

An additional problem: Burning forests for agriculture

Vast forests are being cut down and burned to clear land for ranching, farming, and monocultures. As a tree grows, it absorbs CO2 and converts it into sugar, plant fibre, and wood. Additionally, the tree acts as a carbon stink in which carbon is stored. As the tree decays or burns, this carbon is released...

  • When burned, trees generate more CO2 emissions per unit of energy generated than fossil fuels (Hanson & Ranganathan, 2017)
  • 'Slash and burn' agriculture increases air pollution and the release of carbon into the atmosphere, but also results in significant soil erosion and accompanying landslides, water contamination, and/or dust clouds (Ecologic Development Fund, 2019)
  • Reducing waste also avoids the deforestation for additional farmland, preventing 44.4 gigatons of additional emissions (Project Drawdown, 2017)

Methane emissions

  • More food reaches landfills than any other single material in our everyday trash, constituting 22% of discarded municipal solid waste (EPA, 2015). Here it rots and decomposes under hot and oxygen free conditions buried under mountains of residual waste
  • Due to their organic nature and high moisture content, food scraps decay more rapidly than other organics. Therefore, they produce a disproportionately large component of the methane that landfills produce in the first years (Gunders, 2012)
  • Methane in landfill is roughly 28 times more potent (traps more heat in the atmosphere) than CO2 over its 12 year lifetime (Global Methane Initiative, 2019)
  • If food scraps were removed from landfill, the level of greenhouse gas abatement would be equivalent to removing one-fifth of all the cars in the UK from the road (WRAP, 2011)
  • About 25% of manmade global warming is caused by methane emissions (Environmental Defense Fund, 2019)

An additional problem: Meat production

  • Together, the world’s top five meat and dairy corporations are now responsible for more annual GHG  emissions than Exxon, Shell or BP (GRAIN & IATP, 2018)
  • Global food production accounts for up to 29% of human-induced GHG emissions, while livestock alone accounts for 14.5% (this includes the production of dairy and meat, processing, feed production, storage, manure management, and transportation) (FAO, 2013; Heinrich Böll Stiftung & Friends of the Earth, 2014)
  • Part of the energy ingested as feed is lost in the form of methane (FAO 2006) - about 44% of the sector's emissions are in the form of methane (FAO, 2013) 
  • 25% of global land use, land-use change and forestry emissions are driven by beef production (WWF, 2019)
  • About seven football fields of land are bulldozed worldwide every minute to create more room for farmed animals (Laurance et al., 2002).  More than 90% of the Amazon rainforest that’s been cleared since 1970 is used for meat production (The World Bank, 2004)
  • Global meat production has increased rapidly over the past 50 years - it has grown 4-5 fold since 1961 (OurWorldInData, 2014)
  • Meat food waste has the greatest negative environmental impact (University of Missouri, 2015) - yet of the 352 million tons produced in 2018, 21% of it is wasted, equating to 74 million tons (BCG, 2018)
  • Despite meat being a relatively low contributor to global food waste, only representing 5% (BCG, 2018), it has a significant impact on climate change, contributing to over 20% of the carbon footprint of total food waste (FAO, 2013)
  • It’s hard to believe that belches, farts, and poop from livestock could have any kind of global atmospheric effect, but it’s an issue of scale: there are approximately 1.5 billion cows on the planet, each and every one of them expelling upwards of 30 to 50 gallons of methane each day (Wolf et al., 2017)

"Globally close to 12 billion animals are born to be wasted"

  Oakeshott & Lymbery, 2014

Nitrogen dioxide emissions

  • Incineration has the highest impact (5.5 times higher than anaerobic digestion and 2.5 times higher than landfill) mainly due to the emission of nitrogen dioxide (Tian et al., 2017)
  • CO2 is the currency of climate change and, in those terms, one ton of methane emitted to the atmosphere (for example from livestock) is equivalent to 34 tons of CO2 emissions. In turn, one ton of nitrogen dioxide is equivalent to 298 tons of CO2 (Grace & Barton, 2014)
  • So it has 300 times as much heat-trapping power as CO2 (Mole, 2014)
  • When accounting for the embodied, life-cycle energy — that is, the amount of energy used to source, manufacture, and transport materials for consumption — of solid waste burned at incinerators, there is a net energy loss (ILSR, 2018)
  • Businesses and cities should be aware that burning waste in any form and by any name is a false path to zero waste, and undermines true sustainability goals (GAIA & the Tishman Environment and Design Center, 2017)
  • Even Denmark, heavily reliant on incineration to produce electricity and currently incinerating up to 80% of its organic waste, has decided to slowly move away and instead find a zero waste alternative (The Danish Government, 2013)

An additional problem: Fertilisers

Hydrofluorocarbons emissions

  • Hydrofluorocarbons (HFCs) are man-made fluorinated gases used in cooling and refrigeration (Frischmann, 2018) for perishable food travelling long distances
  • HFCs were developed as alternatives to the ozone depleting substances (ODS) that are being phased-out under the Montreal Protocol  (UNEP, 2019; Fisher & Wilson, 2017)
  • The most abundant HFC is 1,430 times more damaging to the climate than CO2 per unit of mass (Climate & Clean Air Coalition, 2019) and emissions of HFCs are growing at a rate of 10-15% per year.
  • Estimates suggest that 40% of food produced in the world currently requires refrigeration via cold chains (Meneghetti & Monta 2014)
  • Research suggests that each year 360 million tons of perishable foods are lost through insufficient use of refrigeration (International Institute of Refrigeration 2009) - 23% of food waste in developing countries is due to the lack of a cold chain, yet more than 50% of the wasted food could have its shelf-life extended by the cold chain

An additional problem: Distances

  • In the latter half of the 20th century the world's urban population trebled in size and for the first time in human history, more than 50% of people were classed as urban dwellers. By 2050, two thirds of the planet’s population is expected to be living in urban areas (FAO, 2017)
  • We now source food globally and are moving away from the farmlands. For many fresh products, year round availability is maintained by sourcing from different countries as they successively come into season (FAO 2015)