Particulate matter has undoubtedly been a constituent of the atmosphere from the very beginning, and natural processes which existed then continue to make the major contribution to atmospheric turbidity. Volcanic activity, dust storms and a variety of physical and organic processes provide aerosols which are incorporated into the gaseous atmosphere. Human industrial and agricultural activities also help to increase turbidity levels. The aerosols vary in size, shape and composition from fine chemical crystals to relatively large, inert soil particles.

Once into the atmosphere, they are redistributed by way of the wind and pressure patterns, remaining in suspension for periods ranging from several hours to several years, depending upon particle size and altitude attained. The presence of aerosols disrupts the inward and outward flow of energy through the atmosphere. Studies of periods of intense volcanic activity suggest that the net effect of increased atmospheric turbidity is cooling, and some of the coldest years of the Little Ice Age—between 1430 and 1850—have been correlated with major volcanic eruptions. Aerosols produced by human activities cannot match the volume of material produced naturally, but, in the 1960s and early 1970s, some studies suggested that the cumulative effects of relatively small amounts of anthropogenic aerosols could also cause cooling. Present opinion sees atmospheric turbidity actually producing a slight warming. The greatest problem in the study of the impact of atmospheric turbidity on climate is the scarcity of appropriate data and that situation can only be changed by the introduction of systematic observation and monitoring, to complement the theoretical analysis—based on atmospheric modelling techniques—which has been developed in recent years.

The Basic Survival Guide

The Basic Survival Guide

Disasters: Why No ones Really 100 Safe. This is common knowledgethat disaster is everywhere. Its in the streets, its inside your campuses, and it can even be found inside your home. The question is not whether we are safe because no one is really THAT secure anymore but whether we can do something to lessen the odds of ever becoming a victim.

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