Glossary of Terms

Please note that this is an abbreviated list for the benefit of the readers of CCD4E.org.

Aerosol

Small particles or droplets in the atmosphere, with sizes on the order of a micrometre. Taken together they are estimated to exert a cooling effect on the climate

Anthropogenic

Arising because of people

Climate

Averaged properties of the weather, such as temperature, rainfall, taken over some years.

Climate Forcing

This is (loosely) defined as the difference between the incoming energy and the outgoing energy in a given climate system. A positive forcing (more incoming energy) tends to warm the system, while a negative forcing (more outgoing energy) tends to cool it. Example, radiative forcing would be the difference between the incoming radiation energy and the outgoing radiation energy.

Climate Sensitivity

The equilibrium global average warming expected if CO 2 concentrations were to be sustained at double their pre-industrial values (around 560 ppm).

El Nino

An oscillation of the structure of the atmosphere and the ocean, centred in the equatorial Pacific, but with climate impacts around the world

Feedback

A loop of cause and effect. A positive feedback tends to amplify an initial change whereas a negative feedback stabilises the system

Greenhouse Gases

A gas which is capable of absorbing and emitting IR light, for example CO 2 , water vapour, methane, etc.

Weather

The state of the atmosphere at a given time and place, with respect to variables such as temperature, moisture, wind velocity, and barometric pressure.

The above is a rather abbreviated list of common terms used in Climate Science. For a fuller list, the reader is referred to the following site :

http://www.grida.no/publications/other/ipcc_tar/?src=/climate/ipcc_tar/wg1/518.htm