Food Waste and Climate Change

A study by the Food and Agricultural Organization (FAO) of the United Nations takes an interesting look at the environmental impact of food wastage.  The aspect that I found particularly interesting was the impact of global food wastage on the environment, particularly its impact on the climate, a concept that most of us really don't give much thought to.

Globally, the FAO estimated that the total volume of food wasted was 1.6 gigatonnes of "primary product equivalents in 2007 with 1.3 gigatonnes of that being edible food.  This is out of total agricultural production (including non-food items) of 6 gigatonnes.  The biggest waste as a percentage of total production was in fruit followed by vegetables and starchy roots.  Waste can be divided into two types:

1.) Upstream waste: production, post-harvest handling and storage - 54 percent

2.) Downstream waste: processing, distribution and consumption - 46 percent

The level and type of food waste varies around the world and is related to income level.  In high income regions, food waste levels are higher in downstream phases whereas in low income regions, food waste levels are higher in upstream phases.  In the case of high income regions, the higher degree of downstream waste is related to poor planning on the part of consumers, concern over best-before dates and restrictive quality standards that result in over-emphasis on food appearance.  In the case of low income regions, the higher degree of upstream waste is related to limitations on harvesting techniques, storage and transportation issues and climates that favour food spoilage.

Obviously, the production and processing of food has a carbon footprint.  The global carbon footprint of food production in 2007 was estimated at 3.3 gigatonnes of carbon dioxide equivalent.  For comparison's sake, of the world's top greenhouse gas (GHG) emitting nations, China came in first with just over 7 gigatonnes of GHG emissions and the United States came in second with just under 7 gigatonnes of GHG emissions. That puts food waste in third place ahead of Russia with 2 gigatonnes of GHG emissions!  The major contributors to the carbon footprint of food waste are:

1.) cereals - 34 percent

2.) meat - 21 percent

3.) vegetables - 21 percent

Waste of all animal products (i.e meat, eggs, dairy etcetera) accounts for 33 percent of the total carbon footprint however their contribution to food waste volumes is only 15 percent.  Associated with the production of meat from ruminants, methane emissions are a major source of greenhouse gas although some methane is released from the management of manure.  Waste of vegetables accounts for 21 percent of the total carbon footprint however, their contribution to food waste volumes is 24 percent.  The type of food wasted also varies by geographic area.  Waste of cereals and vegetables in Asia is most prevalent while Latin America tends to experience high levels of fruit waste.  

In the case of all foods, emissions of biogenic greenhouse gases from the food itself includes methane and nitrous oxide; methane has a weighting factor of 25 when compared to carbon dioxide and nitrous oxide has a weighting factor of 298 when compared to carbon dioxide.  This food-sourced GHG production is in addition to the emissions related to the use of fuels, fertilizers, emissions from livestock.

Here are the regional results showing the per capita footprint of food wastage in order from highest to lowest (in kilograms of CO2 equivalent):

1.) North America and Oceania - 900 kg

2.) Industrialized Asia - 740 kg

3.) Europe - 680 kg

4.) Latin America - 520 kg

5.) North Africa, Western and Central Asia - 490 kg

6.) South and Southeast Asia - 320 kg

7.) Sub-Saharan Africa - 180 kg

Obviously, the imprint of food waste goes beyond the environmental impact.  It is estimated that based on 2009 producer prices, the value of food wasted globally in 2007 totalled about $750 billion or the approximate GDP of Turkey and Switzerland in 2011.  Vegetables contribute 23 percent to the total economic losses due to food waste, followed by meat at 21 percent, fruits at 19 percent and cereals at 18 percent.  Interestingly, meat accounts for only about 4 percent of the total volume of food wasted however it accounts for 21 percent of the economic value of all food wasted because of its high cost of production.

When food is wasted, this study shows us that there is an associated environmental cost.  Obviously, all of the inputs used in the production of wasted food including fuel, fertilizer and pesticides, each of which has an associated carbon footprint, are themselves wasted.  On top of that, there are the emissions of greenhouse gases from the food items themselves.  This waste puts strain on a food production system that is already suffering from stress, particularly in areas where climate change is already impacting the ability of food producers to produce profitable quantities of primary food products.  At the very least, from this study, we can now understand that our own personal food waste is adding to an already stressed global environment.