Glossary of Environmental Science - G

G

• G8 - The Group of Eight is an international forum for the world's major industrialised democracies that emerged following the 1973 oil crisis and subsequent global recession. It includes Canada, France, Germany, Italy, Japan, Russia, the UK and the US which represents about 65% of the world economy.
• Gaia hypothesis - an ecological hypothesis that proposes that living and nonliving parts of the earth are a complex interacting system that can be thought of as a single organism.
• gene pool - the complete set of unique alleles in a species or population.
• generalist species - those able to thrive in a wide variety of environmental conditions and can make use of a variety of different resources.
• gene - a locatable region of genomic sequence, corresponding to a unit of inheritance, which is associated with regulatory regions, transcribed regions and/or other functional sequence regions.
• genetic diversity - one of the three levels of biodiversity that refers to the total number of genetic characteristics.
• greenhouse effect - the process in which the emission of infrared radiation by the atmosphere warms a planet's surface.
• greenhouse gas - components of the atmosphere that contribute to the greenhouse effect.
• green manure - a type of cover crop grown primarily to add nutrients and organic matter to the soil.
• Green Revolution - the ongoing transformation of agriculture that led in some places to significant increases in agricultural production between the 1940s and 1960s.
• groundwater - water located beneath the ground surface in soil pore spaces and in the fractures of lithologic formation.
• garden organics - organics derived from garden sources e.g. prunings, grass clippings.
• genetic engineering - the use of various experimental techniques to produce molecules of DNA containing new genes or novel combinations of genes, usually for insertion into a host cell for cloning; the technology of preparing recombinant DNA in vitro by cutting up DNA molecules and splicing together fragments from more than one organism; the modification of genetic material by man that would otherwise be subject to the forces of nature only.
• genome – the total genetic composition of an organism
• geosphere - the solid part of planet Earth, the main divisions being the crust, mantle, and liquid core. The lithosphere is the part of the geosphere that consists of the crust and upper mantle.
• geothermal energy - energy derived from the natural heat of the earth contained in hot rocks, hot water, hot brine or steam.
• global acres see global hectares.
• global dimming – a reduction in the amount of direct solar radiation reaching the surface of the earth due to light diffusion as a result of air pollution and increasing levels of cloud. A phenomenon of the last 30–50 years.
• economic globalization - the emerging international economy characterized by free trade in goods and services, unrestricted capital flows and more limited national powers to control domestic economies.
• global hectares - acres/hectares that have been adjusted according to world average biomass productivity so that they can be compared meaningfully across regions; 1 global hectare is 1 hectare of biologically productive space with world average productivity.
• global warming potential - a system of multipliers devised to enable warming effects of different gases to be compared.
• global warming – the observable increase in global temperatures considered mainly caused by the human induced enhanced greenhouse effect trapping the Sun’s heat in the Earth’s atmosphere.
• globalisation – the expansion of interactions to a global or worldwide scale; the increasing interdependence, integration and interaction among people and organisations from around the world. A mix of economic, social, technological, cultural, and political interrelationships.
• glyphosate – the active ingredient in the herbicide RoundupTM.
• governance – the decision-making procedure; who makes decisions, how they are made, and with what information. The structures and processes for collective decision-making involving governmental and non-governmental actors.
• green architecture - building design that moves towards self-sufficiency sustainability by adopting circular metabolism.
• green design - environmentally sustainable design.
• green power - Electricity generated from clean, renewable energy sources (such as solar, wind, biomass and hydro power) and supplied through the grid.
• green products and services - products or services that have a lesser or reduced effect on human health and the environment when compared with competing products or services that serve the same purpose. Green products or services may include, but are not limited to, those which contain recycled content, reduce waste, conserve energy or water, use less packaging, and reduce the amount of toxics disposed or consumed.
• green purchasing - purchasing goods and services that minimise impacts on the environment and that are socially just.
• Green Star – a voluntary building rating for green design covering 9 impact categories up to 6 stars which equals world leader.
• green waste (green organic material or green organics, sometimes referred to as "green wealth") - plant material discarded as non-putrescible waste - includess tree and shrub cuttings and prunings, grass clippings, leaves, natural (untreated) timber waste and weeds (noxious or otherwise).
• green – (sustainability) like ‘eco’ - a word frequently used to indicate consideration for the environment e.g. green plumbers, green purchasing etc., sometimes used as a noun e.g. the Greens.
• greenhouse effect - the insulating effect of atmospheric greenhouse gases (e.g., water vapor, carbon dioxide, methane, etc.) that keeps the Earth's temperature about 60 °F (16 °C) warmer than it would be otherwise cf. enhanced greenhouse effect.
• greenhouse gases - any gas that contributes to the greenhouse effect; gaseous constituents of the atmosphere, both natural and from human activity, that absorb and re-emit infrared radiation. Water vapor (H2O) is the most abundant greenhouse gas. Greenhouse gases are a natural part of the atmosphere and include carbon dioxide (CO₂), methane (CH₄, persisting 9-15 yrs with a greenhouse warming potential (GWP) 22 times that of CO₂), nitrous oxide (N₂O persists 120 years and has a GWP of 310), ozone (O₃),hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride.
• greenlash – dramatic changes in the structure and dynamic behaviour of ecosystems.
• greenwashing - companies that portray themselves as environmentally friendly when their business practices do not back this up. Generally applies to excessive use of green marketing and packaging when this does not take account of the total ecological footprint.
• greenwater – water replenishing soil moisture, evaporating from soil, plant and other surfaces, and transpired by plants. In nature the global average amount of rainfall becoming green water is about 60%. Of the green water about 55% falls on forests, 25% on grasslands and about 20% on crops. We can increase green water productivity by rainwater harvesting, increased infiltration and runoff collection. Green water cannot be piped or drunk (cannot be sold) and is therefore generally ignored by water management authorities but it is crucial to plants in both nature and agriculture and needs careful management as an important part of the global water cycle.
• greywater – household waste water that has not come into contact with toilet waste; includes water from baths, showers, bathrooms, washing machines, laundry and kitchen sinks.
• gross primary productivity - total carbon assimilation.
• groundwater – water found below the surface – usually in porous rocks, or soil, or in underground aquifers.
• growth – increase in size, weight, power etc.