Glossary of terms
Here you will find definitions of terms used in resources on the Foodsource website. You will also find these definitions on the right-hand side within chapters. If you have any suggestions for new glossary items, let us know here.
Ozone layer depletion
A decline in the level of ozone gas (O3) present in the earth's stratosphere, owing to its breakdown into oxygen (O2). This breakdown can be affected by natural processes, but is known to have been accelerated by the release of man-made chemicals, such as refrigerant gases. The ozone layer acts to reduce the amount of light at ultra-violet wavelengths reaching the earth's surface; wavelengths that can have harmful impacts on humans, including skin cancer.
Photochemical smog is observed as a haze in the atmosphere, typically near to cities. It is created through the action of sunlight on pollutants (nitrogen oxides and volatile organic compounds) emitted by automobiles and other industrial sources, which creates other pollutants harmful to health, such as ozone.
Planetary boundaries concept
The planetary boundaries concept refers to the idea that humans are substantially altering natural systems, and that beyond a certain level of change this may become irreversible and self sustaining. The potential result is a planet with environmental conditions that differ substantially from those in which human civilisation developed and to which many species and ecosystems are adapted. Planetary boundaries have so far been proposed for climate change, biodiversity loss, biogeochemical cycles, ocean acidification, land use, freshwater, and ozone depletion.
Price elasticity refers to how much the demand for a good is affected by a change in its price. A good is said to be price inelastic if a change in price means that there is little change in demand. An example might be medication or addictive substances, like tobacco. A good is said to be price elastic if a change in price greatly changes the demand for the good.
Public procurement refers to the acquisition of goods, services or work by public bodies such as government agencies, hospitals, and schools, or by state owned enterprises such as railways or energy providers. Such spending can represent a substantial amount of taxpayers' money and of gross domestic product in many countries, and so how it is spent is a matter of public interest. Beause of this, changing public procurement is often seen as a way in which to influence business practices.
Ruminant animals are distinguished by their specialised digestive system and include species such as cattle, sheep, goats, deer, and camels. In particular, their large rumen stomach allows plant matter to be regurgitated, chewed again, and for microbes to ferment it. This breaks down plant matter into digestible molecules that can be absorbed by the animal and allows ruminants to be fed on coarse plant matter such as grass, whereas other species such as pigs and chickens cannot.
Selective breeding refers to the deliberate human practice of choosing which plants or animals to breed together, based on specific characteristics, in order to selectively enhance these characteristics (and their genetic basis) in their offspring.
Sensitivity and uncertainty analysis
Sensitivity and uncertainty analysis are an integral part of any modelling process. Sensitivity analysis varies the possible values of input variables to a model in order to understand the difference that these assumptions make to results and conclusions that can be drawn. Uncertainty analysis investigates the potential effects of lack of knowledge or potential errors in the model design.
Silting refers to the transport and deposition of sediment on the riverbed, which changes the dynamics of the water flow and can affect aquatic ecosystems.
Stunting is a medical condition where childhood growth and development is impared as a result of inadequate nutrition, repeated infection, and inadequate psycosocial stimulation. Children are definied as stunted if their height for their age is abnormally low. Its effects can lead to an under developed brain, poor cognition and educational attainment, as well as higher risk of nutrition related chronic diseases in later life.
Subsistence farming refers to rearing animals and growing crops only for your own consumption, without having any surplus to take to market as a source of cash income.
In economics, the substitution effect refers to the idea that as prices increase or as a product becomes scarce, people will replace such items with substitutes that are cheaper or easier to access. In the context of diets, substitution effects refer to the changes in the environmental footprint of a person's diet, according to the relative impact of foods that are substituted for one another.
The subjective boundaries that define what is included within the system under analysis (and so counted) and what is external to the system (and so not counted). System boundaries have multiple dimensions, including what stages are focused on (e.g. production, distribution), what inputs and outputs are measured (e.g. land, greenhouse gases), what geographic locations are included, and more.
Turbidity refers to the amount of light that can pass through water (i.e. its cloudiness), as a result of particles that are suspended within the fluid. It can vary naturally depending on location, but can have detrimental impacts on ecosystems if cause by human activity. For this reason, it is often used as an indicator of water quality.
Water footprint is a metric that quantifies the amount of water used to produce each of the goods and services we use. It allows these goods and services to be compared in terms of their water impact, and so to the impact on limited water resources of consumption by individuals, organisations, and even nation states. Water footprints incorporate all the water used – i.e. unable to be used again due to evaporation or removal in products – across the full lifecycle of a produce from production through to consumption, including all inputs to production (e.g. feed crops used in pork production). It has three components: (1) green water - rainwater used in soils; (2) blue water - freshwater sources; (3) grey water - water amount needed to dilute pollution to safe levels.