To Human Interference

The impact of society on the environment depends not only on the nature of society, but also on the nature of the environment. Although it is common to refer to 'the' environment, there are in fact many environments, and therefore many possible responses to human interference. Individually, these environments vary in scale and complexity, but they are intimately linked, and in combination constitute the whole earth/ atmosphere system (see Figure 1.2). Like all systems, the earth/atmosphere system consists of a series of inter-related components or subsystems, (see Figure 1.3) ranging in scale from microscopic to continental, and working together for the benefit of all. Human interference has progressively disrupted this beneficial relationship. In the past, disruption was mainly at the sub-system level—contamination of a river basin or pollution of an urban environment, for example—but the integrated nature of the system, coupled with the growing scale of interference caused the impact to extend beyond individual environments to encompass the entire system.

In material terms the earth/atmosphere is a closed system, since it receives no matter (other than the occasional meteorite) from beyond its boundaries. The closed nature of the system is of considerable significance, since it means that the total amount of matter in the system is fixed. Existing resources are finite; once they are used up they cannot be replaced. Some elements—for example, water, carbon, nitrogen, sulphur—can be used more than once because of the existence of efficient natural recycling processes which clean, repair or reconstitute them. Even they are no longer immune to disruption, however. Global warming is in large part a reflection of the inability of the carbon cycle to cope with the additional carbon dioxide introduced into the system by human activities.

The recycling processes and all of the other sub-systems are powered by the flow of energy through the system. In energy terms the earth/ atmosphere system is an open system, receiving energy from the sun and returning it to space after use. When the flow is even and the rates of input and output of energy are equal, the system

Figure 1.2 Schematic diagram of the earth/atmosphere system energy flow system - open

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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