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G77/China
See Group of 77 and China.

GDP
See Gross Domestic Product.

General equilibrium analysis
General equilibrium analysis is an approach that considers simultaneously all the markets and feedback effects among these markets in an economy leading to market clearance. See also market equilibrium.

Geo-engineering
Efforts to stabilise the climate system by directly managing the energy balance of the earth, thereby overcoming the enhanced greenhouse effect.

GHG
See greenhouse gas.

Global warming
Global warming is an observed or projected increase in global average temperature.

Global Warming Potential (GWP)
An index, describing the radiative characteristics of well-mixed greenhouse gases, that represents the combined effect of the differing times these gases remain in the atmosphere and their relative effectiveness in absorbing outgoing infrared radiation. This index approximates the time-integrated warming effect of a unit mass of a given greenhouse gas in today’s atmosphere, relative to that of carbon dioxide. Note that GWP also stands for Gross World Product.

GNP
See Gross National Product.

GPP
See Gross Primary Production.

Greenhouse effect
Greenhouse gases effectively absorb infrared radiation emitted by the earth’s surface, by the atmosphere itself from these same gases, and by clouds. Atmospheric radiation is emitted to all sides, including downwards to the earth’s surface. Thus, greenhouse gases trap heat within the surface–troposphere system. This is called the natural greenhouse effect. Atmospheric radiation is strongly coupled to the temperature of the level at which it is emitted. In the troposphere the temperature generally decreases with height. Effectively, infrared radiation emitted to space originates from an altitude with a temperature of, on average, –19°C, in balance with the net incoming solar radiation. However, the earth’s surface is kept at a much higher temperature of on average +14°C. An increase in the concentration of greenhouse gases leads to an increased infrared opacity of the atmosphere, and therefore to an effective radiation into space from a higher altitude at a lower temperature. This causes a radiative forcing, an imbalance that can only be compensated for by an increase in the temperature of the surface–troposphere system. This is the enhanced greenhouse effect.

Greenhouse gas (GHG)
Greenhouse gases are those gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of infrared radiation emitted by the earth’s surface, the atmosphere, and clouds. This property causes the greenhouse effect. Water vapour (H₂O), carbon dioxide, nitrous oxide, methane and ozone (O₃) are the primary greenhouse gases in the earth’s atmosphere. Moreover, there are a number of entirely human-made greenhouse gases in the atmosphere, such as the halocarbons and other chlorine- and bromine-containing substances, dealt with under the Montreal protocol. Beside carbon dioxide, nitrous oxide and methane, the Kyoto Protocol deals with the greenhouse gases sulphur hexafluoride, hydrofluorocarbons, and perfluorocarbons.

Gross World Product (GWP)
An aggregation of the Gross Domestic Products of the world. Note that GWP also stands for Global Warming Potential.

Gross Domestic Product (GDP)
The sum of gross value added, at purchasers’ prices, by all resident and non-resident producers in the economy, plus any taxes and minus any subsidies not included in the value of the products in a country or a geographic region for a given period of time, normally 1 year. It is calculated without deducting for depreciation of fabricated assets or depletion and degradation of natural resources

Gross National Product (GNP)
GNP is a measure of national income. It measures value added from domestic and foreign sources claimed by residents. GNP comprises Gross Domestic Product plus net receipts of primary income from non-resident income.

Gross Primary Production (GPP)
The amount of carbon fixed from the atmosphere through photosynthesis.

Group of 77 and China (G77/China)
Originally 77, now more than 130 developing countries that act as a major negotiating bloc in the UNFCCC (United Nations Framework Convention on Climate Change) process. G77/China is also referred to as non-Annex I countries in the context of the United Nations Framework Convention on Climate Change.

GWP
See Global Warming Potential, Gross World Product.

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