Introduction

Substantial changes in the environment caused by human industrial activities, and their possible climatic impact, have become matters of very great concern, because variations in climate can seriously affect agricultural productivity and many other aspects of human activity. Serious attention has recently been given, for example, to the possible effects of the increase of CO2 and other greenhouse gases in the atmosphere. There are numerous interacting factors causing climate change, which have a complex system of interactions in the climate system: atmosphere; biosphere; hydrosphere; lithosphere; and cryosphere. Three categories of events that affect the climate are: events that occur outside the Earth; natural events on the surface of, or within, the Earth; and human activities. The human activity of which we are most aware, in common culture, in terms of its effect on the global environment is the production of CO2 by the burning of fossil fuels.