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3.9 CSIRO graph of increase of CO 2 levels in the atmosphere since AD1000.
about 55 km. Ozone is a form of oxygen, (O 3 ), having three atoms to the
molecule. It is produced by the action of solar radiation on oxygen, and is a
powerful oxidising agent. The ozone layer guards the troposphere and the land
surface from the effects of excessive amounts of ultraviolet radiation from the
Sun's rays, thus playing an essential role in environmental protection. Synthetic
compounds containing carbon, fluorine and chlorine atoms released into the
atmosphere pose a serious threat of global warming by attacking molecules of
ozone and converting them back to oxygen. So-called `holes' in the ozone layer
at the southern and northern polar-regions have been observed from studies
based upon satellite data since the 1980s. The `holes' relate to thinning of the
ozone layer, the maximum thinning occurring at the time of minimum surface
temperature. The intensity varies from time to time but a strong general trend
towards greater seasonal thinning and global warming is of great concern.
3.2.2 Oceanic±atmospheric relations
The interface between atmosphere and land constitutes a region in which there is
a continual interflow of matter and energy with atmospheric conditions exerting
control on the land surface while the land surface exerts an influence on the
properties of the adjacent atmosphere. A similar interface exists between the
atmosphere and the surface of the oceans in contact with it. The oceans influence
the atmosphere above it; the atmosphere exerts control over the sea beneath it.
Different reactions of land and sea to insolation significantly affect both
global climates and local weather patterns at land-sea boundaries. The oceans
warm and cool at lower rates than the atmosphere but due to the greenhouse
effect the oceans are slowly warming. This will have a delayed warming effect
upon the Earth's atmosphere in the coming centuries, affecting the Earth's other
