Introduction OUR SOURCES The greenhouse effect is a sustained, natural phenomenon: gases which are radiatively active have ’warmed’ the surface of the Earth since the planet and its atmosphere were formed about four and a half billion years ago. Mankind’s activities, particularly those associated with industrialization, large-scale land clearance and chemically improved agriculture, are adding increasingly large amounts of these radiatively active gases to the atmosphere. At present there seems little likelihood that this global scale atmospheric pollution will cease much less that removal of the pollutants will be initiated. This planet therefore seems to be committed to a global scale warming, an intensification of the hydrological cycle (the coupled processes of evaporation, cloud formation, precipitation and runoff) and many associated climatic shifts. It is thus essential that policies be developed which recognize the reality of the predicted changes. The greenhouse e
what is greenhouse effect and causes