Food and the planet

We are all part of a giant food web. In a food web, energy flows from the sun, to plants and then to animals.

Primary producers (plants) use energy from the sun to produce their own food (glucose). Primary producers are eaten by primary consumers who are in turn eaten by secondary consumers. Energy flows from one trophic level to the next.

Energy is lost as it moves along a food chain. There are three main ways in which energy is lost. These are:

RESPIRATION to generate energy for movement and organ functioning
EXCRETION as faeces and urine
TISSUE (biomass) generation

Only 10% of the energy (in tissue) is transferred between trophic levels. For example, a lot of grass can grow using the energy from the sun. When a rabbit eats the grass, it needs to eat a lot of grass (it also then eats its own poo) to get as much energy as possible from the grass. The rabbit loses energy through excrement, keeping warm and respiration. To get enough energy a fox then needs to eat many rabbits to get the energy it needs. The flow of energy through a food chain limits how long the chain can be.

Humans can be primary consumers (herbivores) and eat plants. Eating plants in their raw form provides us with a greatest range of vitamins and fibre. Cooking often depletes vitamins in food. Humans can also be secondary and tertiary consumers (carnivores) and eat meat. Eating meat provides protein and minerals.

Where in the food web we eat, has a big impact on the planet. What we ultimately eat depends on a wide range of factors including accessibility, cost, personal beliefs, allergies, likes and dislikes.

Every food has a different journey and a different environmental impact, which can make it very confusing!

Food's carbon footprint is the greenhouse gas (GHG) emissions produced by growing, rearing, farming, processing, transporting, storing, cooking, and disposing of the food.

GHG emissions associated with a product, along its supply-chain, and sometimes includes emissions from consumption, end-of-life recovery and disposal.

A carbon footprint is usually expressed in kilograms or tonnes of carbon dioxide equivalent (CO2-eq.).

The impact of WORLD food production on the planet

There are many different ways of producing food. The journey that food comes on to reach you has different steps along the way. How food is produced has a BIG impact on the planet.

Before the food even reaches you, there have been greenhouse gas emissions from land use changes, farming, feeding, processing, transporting, selling and packaging. When you prepare and eat the food and what you do with the waste then generate more emissions.

We live in a global society and when we look at the greenhouse gases produced by food production, we have two categories of emissions:

those produced when the food is produced
those produced when the food is consumed.

When food is produced and eaten in Scotland we can look at the whole environmental footprint of the food. However, we produce some foods in Scotland that are exported for example lamb and whisky. We also consume food in Scotland that has been imported for example coconuts and rice. In these cases it is very hard to understand the whole environmental impact of the food because we need to look at all the steps in the food chain.

Global food chains are generally long and involve many steps.

Global food chains are big and complex. They are often able to produce more affordable food due to economy of scale. A global scale also means a greater product availability as you have the pick of the best of the crop.

Global food chains focus on the volume of food they can produce and process to maximise the income they can make. This can mean less thought is given to the impact on the environment and the fair treatment of employees.

Local supply chains are generally shorter and involve fewer steps.

Local food chains generally involve fewer people and links which means they are shorter. For example, a local farmer producing milk which is sold directly to the public or a beef farmer selling meat to a butcher. Where local people support local food supply chains the businesses are in a position to in turn support the local community.

Local food chains focus on quality rather than volume. The producers are generally more aware of how the food is produced and work to look after the land and the people they employ.

🎲Look at the video and the image below. Do you think workers' rights are the same in Scotland and Uganda? What might the similarities and differences be?

Chemicals and food

Farmers often use chemicals to help prevent disease and help growth in both crops and livestock. For example livestock wormers are used on sheep and cattle. Wormers kill the tiny parasitic worms that live inside the sheep or cow and by using worming medicine; this will help keep the animal healthy.

A crop based example, is the spraying of oilseed rape against attack from flea beetles. The cabbage stem flea beetle eats the oilseed rape plants and to control beetle numbers the crop is sprayed with insecticide that kills the beetles.

Using any chemicals requires great care to prevent damage to the environment. If too much chemical is used it can cause problems in the wider environment.

Anyone using these chemicals are inspected annually to ensure the storage and application is correct/compliant.

Water and food production

Producing food requires water. Some crops get all the water they need from the rain whilst other crops require irrigation (watering) for example potatoes grown in Egypt.

Water use for crop growth varies around the world. In hot climates like Egypt, any water used to give the plants a drink evaporates quickly and leaves the salts in the water behind. Over time this makes the soil salty and not as good for growing more crops.

In Scotland, we have plenty of rain so only a few crops require irrigation like carrots and potatoes. Livestock also require access to fresh water for drinking