Environmental issues glossary

A glossary of words and phrases used in green construction and sustainable development.

G

Geographical information systems (GIS)

Detailed information on the soils, hydrology, land use patterns, and plant and animal habitats of sites, plotted on maps or entered in databases and employed to evaluate appropriate location of buildings and infrastructure, and to plan landscaping and other land use considerations.

Geothermal energy

Literally, the heat of the earth. Where this heat occurs close to the earth's surface, and is able to maintain a temperature in the surrounding rock or water at or above 150 degrees C, it may be tapped to drive steam turbines.

Genuine progress indicator

This measures real personal consumption spending, adjusts for income distribution, then adds or subtracts to reflect ecological and social benefits or costs.

Geotextile

A variety of fabrics made from recycled materials used in soil containment and stabilisation.

Globalisation

The process enabling financial and investment markets to operate internationally, largely as a result of deregulation and improved communications. Transnational companies have both helped the process and benefited from it.

Global economy

Refers to the emerging international economy characterised by free trade in goods and services, unrestricted capital flows and weakened national powers to control domestic economies.

Global hectare

One hectare of biologically productive space adjusted to world average Biomass productivity allowing meaningful comparisons across regions to be made.

Global warming

An increase in the near surface temperature of the earth; global warming is most often used to refer to the warming predicted to occur as a result of increased emissions of Greenhouse gases.

Global Warming Potential (GWP)

Anumerical index that allows effects on global warming of various Greenhouse gases to be compared, using the 100 year GWP of Carbon dioxide as a reference point. Carbon dioxide has a GWP of 1, Methane has a GWP of 21; the GWP’s of various Hydrofluorocarbons range from 140 - 11,700.

Grandfathering

Granting an existing firm a legal exemption from a new or changed policy. In the case of tradable permits, it refers to the common practice of allocating permits to existing polluters or users of natural resources at no direct cost to them.

Greenbelt or Greenfield

Area of land often encircling a city, with extra planning restraints on development; undeveloped land. The term was first used in London in the 1940s.

Greenfield runoff

This is the surface water Runoff regime from a site before development, or the existing site conditions for Brownfield redevelopment sites.

Green roof

A roof with plants growing on its surface contributing to local Biodiversity. The vegetated surface provides a degree of retention, Attenuation and treatment of rainwater, and promotes Evapotranspiration.

Greenhouse effect

The roles of water vapour, Carbon dioxide, and other trace gases in keeping the Earth's surface warmer than it would be otherwise; they trap long wave radiation, which would otherwise escape to space, within the lower levels of the atmosphere; the subsequent reradiation of some of the energy back to the surface maintains surface temperatures higher than they would be if the gases were absent. This process occurs naturally and has kept the earth's temperature about 12oC warmer than it would otherwise be; current life on earth could not be sustained without the natural greenhouse effect. However, increased emissions of Greenhouse gases may increase the surface temperature of the earth with potentially serious consequences.

Greenhouse gases

Any gas that absorbs infrared radiation in the atmosphere. Greenhouse gases include water vapour, Carbon dioxide (CO2), Methane (CH4), Nitrous oxides, halogenated fluorocarbons (HCFCs), Ozone (O3), perfluorinated carbons (PFCs) and Hydrofluorocarbons (HFCs).

Greenwash

To falsely claim a product is environmentally sound, or to unfoundedly bolster a product, or structures, environmental credentials. Also known as faux greening.

Greywater

Water from sinks and baths that may be reused for watering, landscaping and other domestic purposes, before it reaches the sewer (or septic tank system); usually water that has been used for showering, clothes washing, and bathing.

GRI (Global Reporting Initiative)

A multi-stakeholder process and independent institution whose mission is to develop and disseminate globally applicable Sustainability Reporting Guidelines.

Ground source heat pump

See – Heat pumps

Groundwater

Water that is below the surface of ground in the saturation zone.

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