This page is part of the Earth Journalism Toolkit’s glossary.

Ecological Goods and Services: Products (such as timber, medicines, wild foods) and services (such as climate regulation, water purification, pollination of crops) that nature provides to humanity.

Ecologist: A biologist who studies ecology.

Epidemiologist: a medical scientist who studies the transmission and control of epidemic diseases.

Ecosystem: Whole complex of relationships between species among themselves and with the inert medium in which they operate. The ecosystem includes the biota and habitat.

Epidemiology: The study of the occurrence and causes of health effects in human populations. An epidemiological study often compares two groups of people who are alike except for one factor such as exposure to a chemical or the presence of a health effect. The investigators try to determine if the factor is associated with the health effect.

Endemic: A living species that is only present in a given region (a mountain, an island, a valley, a country, etc.).

Environmental impact assessment (EIA): Environmental impact assessment is an assessment of the likely positive and/or negative influence a particular project may have on the environment.

Exposure: Contact with a chemical by swallowing, by breathing or by direct contact (such as through the skin or eyes). Exposure may be either short term (acute) or long term (chronic).

Epidemic: a widespread outbreak of an infectious disease in which many people are infected at the same time.

Eco-label: a seal or logo indicating a product has met a certain environmental or social standards.

Ecological Footprint: a measure of the area of biologically productive land and water needed to produce the resources and absorb the wastes of a given population (e.g. a country, a region or the whole world).

Ecology: the scientific study of living organisms and their relationships to one another and their environment; the scientific study of the processes regulating the distribution and abundance of organisms; the study of the design of ecosystem structure and function.

Externality: a cost or benefit that is not borne by the producer or supplier of a good or service. In many environmental situations environmental deterioration may be caused by a few while the cost is borne by the community; examples would include overfishing, pollution (e.g. production of greenhouse emissions that are not compensated for in any way by taxes etc.), the environmental cost of land-clearing etc.

Ecosystem services: the benefits that nature provides to humanity, from production of oxygen to soil formation, maintenance of water quality provision of wild foods, etc., These services are now generally divided into four groups, supporting, provisioning, regulating and cultural.

Ecosystem: a dynamic complex of plant, animal and microorganism communities and their non-living environment all interacting as a functional unit.

Energy efficiency: using less energy to provide the same level of energy service.

Effluent: a discharge or emission of liquid, gas or other waste product.

El Niño: a warm water current which periodically flows southwards along the coast of Ecuador and Peru in South America, replacing the usually cold northwards flowing current; occurs once every five to seven years, usually during the Christmas season; the opposite phase is called a La Niña.

Emissions: substances such as gases or particles discharged into the atmosphere as a result of natural processes of human activities, including those from chimneys, elevated point sources, and tailpipes of motor vehicles.

Endangered species: a species which is at risk of becoming extinct because it is either few in number, or threatened by human activities or changing environmental conditions.

Erosion: displacement of solids (sediment, soil, rock and other particles) usually by the agents of currents such as, wind, water, or ice by downward or down-slope movement in response to gravity or by living organisms.

Eutrophication: the enrichment of water-bodies with nutrients, primarily nitrogen and phosphorus, which stimulates the growth of aquatic organisms.

Evaporation: water converted to water vapour.

Evapotranspiration: the water evaporating from the soil and transpired by plants.

E-waste: electronic waste, especially mobile phones, televisions and personal computers.

Fertility rate: number of live births per 1,000 women aged 15 to 44 years.

Fertilizers (also spelled fertilisers): compounds given to plants to promote growth; they are usually applied either through the soil, for uptake by plant roots, or by foliar feeding, for uptake through leaves.

Food chain (food webs, food networks and/or trophic networks): describe the feeding relationships between species within an ecosystem.

Food miles: the emissions produced and resources needed to transport food and drink around the globe.

Food security: global food security refers to food produced in sufficient quantity to meet the full requirements of all people

Forest: land with a canopy cover greater than 30%.

Fossil fuel: any hydrocarbon deposit that can be burned for heat or power, such as coal, oil and natural gas (produces carbon dioxide when burnt); fuels formed from once-living organisms that have become fossilized over geological time.

Freshwater: water containing no significant amounts of salt.