334 Glossary
Business-as-usual The scenario for future world patterns of energy consumption
andgreenhouse gasemissions which assumes that there will be no major
changes in attitudes and priorities
C3, C4 plants Groups of plants which take upcarbon dioxidein different ways in
photosynthesisand are hence affected to a different extent by increased
atmospheric carbon dioxide. Wheat, rice and soya bean are C3 plants; maize,
sugarcane and millet are C4 plants
Carbon cycle The exchange of carbon in various chemical forms between the
atmosphere, the land and the oceans
Carbon dioxide fertilisation effect The process whereby plants grow more
rapidly under an atmosphere of increased carbon dioxide concentration. It
affectsC3 plantsmore thanC4 plants
Carbon dioxide One of the major greenhouse gases. Human-generated carbon
dioxide is caused mainly by the burning of fossil fuels and deforestation
Celsius Temperature scale, sometimes known as the Centigrade scale. Its fixed
points are the freezing point of water (0◦C) and the boiling point of water
(100◦C)
CFCs Chlorofluorocarbons; synthetic compounds used extensively for
refrigeration and aerosol sprays until it was realised that they destroy ozone
(they are also very powerful greenhouse gases) and have a very long lifetime
once in theatmosphere. The Montreal Protocol agreement of 1987 is resulting
in the scaling down of CFC production and use in industrialised
countries
Chaos A mathematical theory describing systems that are very sensitive to the
way they are originally set up; small discrepancies in the initial conditions will
lead to completely different outcomes when the system has been in operation
for a while. For example, the motion of a pendulum when its point of
suspension undergoes forced oscillation will form a particular pattern as it
swings. Started from a slightly different position, it can form a completely
different pattern, which could not have been predicted by studying the first one.
The weather is a partly chaotic system, which means that even with perfectly
accurate forecasting techniques, there will always be a limit to the length of
time ahead that a useful forecast can be made
CIS Commonwealth of Independent States (former USSR)
Climate sensitivity The global average temperature rise under doubledcarbon
dioxideconcentration in theatmosphere
Climate The average weather in a particular region
Compound A substance formed from two or more elements chemically combined
in fixed proportions
Condensation The process of changing state from gas to liquid
Convection The transfer of heat within a fluid generated by a temperature
difference
Coppicing Cropping of wood by judicious pruning so that the trees are not cut
down entirely and can regrow
Cryosphere The component of the climate system consisting of all snow, ice and
permafrost on and beneath the surface of the earth and ocean