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.

2 (1) | A (13) | B (6) | C (15) | D (6) | E (8) | F (12) | G (4) | H (3) | I (7) | L (5) | M (12) | N (7) | O (4) | P (9) | R (7) | S (10) | T (1) | U (2) | W (4) | Y (1) | Z (2)

Functional unit

A functional unit refers to the product, service, or system whose impacts are calculated by a life-cycle assessment (LCA). Common examples of food-related functional units are 1 kg of beef, 100 calories of food, or 1 ha of land. The choice of functional unit influences an LCA’s results and care is needed when comparing the results of LCAs with different functional units. The functional unit is defined in the first phase of a life-cycle assessment study – that of goal and scope definition.

Generalist species

A generalist species is a plant or animal species that is able to thrive in a large variety of environmental conditions, or that can live on a wide variety of foods. Members of the same generalist species can often be found at different parts of landscapes and in different regions of the world.


GHGs is an abbreviation for greenhouse gases. These include gases such as carbon dioxide, methane, and nitrous oxide, which affect outgoing radiation, leading to global warming.

Global warming potential

Global warming potential (GWP) refers to quantifying the strengths of different greenhouse gas emissions relative to carbon dioxide (CO2). Derived from estimating the total change in atmospheric energy balance resulting from a pulse emission of the gas, relative to CO2, over a specified time-frame (typically 100 years).


GWP* is an alternative application of Global Warming Potential to derive carbon dioxide equivalents (referred to as CO2e* if using GWP*) that primarily relates the change in the rate of short-lived greenhouse gases (such as methane) to a fixed quantity of CO2, rather than a direct equivalence between emissions of both short- and long-lived greenhouse gases, as is the case for conventional use of the 100-year Global Warming Potential.

Habitat fragmentation

Habitat fragmentation describes the breakup (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay.


Hydrogenation is a chemical reaction between a hydrogen molecule (H2) and another molecule or element in the presence of a catalyst such as palladium, platinum or nickel. In the food industry, hydrogenation is often used to turn liquid oils into solid fats. The partial hydrogenation of oils is used to produces trans-fats. Hydrogenated fats and trans-fats are contested for their health impacts.

Hydroxyl (OH) radicals

Hydroxyl (OH) radicals are highly reactive molecules responsible for the initial reaction leading to most methane destruction in the atmosphere, and also important for the removal of many other atmospheric pollutants. Radicals are molecules or atoms with an unpaired electron, often making them very reactive.

Industrial food manufacturing

Industrial food manufacturing refers to the large-scale production of food products by processing companies using highly mechanised assembly lines and according to pre-defined specifications that guarantee the production of a product with a constant quality. Most of these foods are produced for the retail and consumer market.


Intensification refers to a process by which farming systems (for crops or livestock) are reorganised – often through the application of new technologies, economies of scale, and the use of additional inputs, such as nutrients, chemicals, energy and water – in order to produce more of a desired output (e.g. meat) while using less land, human labour, or capital. The result is that the costs of production for a given amount of food are reduced, thereby increasing profits through larger profits per unit of food, or by expanding total consumption through lower prices, enabling more people to buy more. Often, environmental impacts per unit of product are also reduced, but may be counterbalanced by increases in total production. The impacts of intensification processes on animal welfare, biodiversity, and other issues is also a widely held concern.

Intensive agriculture

Intensive agriculture (IA) is often used synonymously with the terms industrial agriculture and conventional farming. IA is generally used to denote farming systems that use modern technologies and economies of scale to maximise yields relative to land use and production costs (e.g. costs of labour, technology, seeds, fertilisers, and pesticides). IA is associated with high use of chemical fertilisers, agrochemicals, and irrigation. This combination of agricultural technologies became common during the Green Revolution in the mid-20th century and has long been criticized for its high social and environmental impacts.

Interstitial waters

Interstitial waters refers to water trapped in sediments or in pores (voids or spaces) in sedimentary rocks – rocks formed by the deposition and cementation of material, as opposed to rocks formed by volcanic processes.


The Intergovernmental Panel on Climate Change (IPCC) is the international body for assessing the science related to climate change. It is administered by the United Nations with participation and decision making from 195 member states. The assessments that it produces provide the basis for government at all levels to create climate related policies.


Iso-calorific is a term that means to hold the amount of calories in a diet constant, while changing other variables. It is used in research as a way to make meals with different compositions in terms of foods and nutrients, equivalent and comparable in terms of the energy that they provide.

Isotopic signature

Isotopic signature refers to the ratio of different isotopes. Isotopes are atoms that have a different number of protons and neutrons. For example, most carbon (C) has 6 protons and 6 neutrons, giving it an atomic weight of 12. This form of carbon is known as carbon-12 (or 12C). Another stable form of carbon exists with 6 protons and 7 neutrons, giving it a molecular weight of 13, hence it is known as carbon-13 (or 13C). Different sources of methane emissions can be composed of different proportions of 12C and 13C, with fossil fuel sources often containing relatively more 13C than biological sources.