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HUMANS, THE ENVIRONMENT AND ENVIRONMENTAL CHANGE

Click on the links below to view specific sections of the sample material:

OVERVIEW

This chapter sets down the basis of a new physical geography. It starts by taking a novel
view of the subject, in which humans and the human-altered environment are set on an equal
footing with the natural environment. This viewpoint is justified by the ever-increasing
domination of the planetary surface by the human species, which has drastically altered the
natural flows of gases, soluble materials and solids, and transformed the land-cover, reducing
biodiversity through species extinctions in the process. This new view also sees the Earth as a
global ecosystem.

The ‘Earth system’ thus described can be measured, monitored and mapped using remote sensing and other sophisticated techniques (as well as simple ones); and it can be modelled using high-powered computers (and humble PCs too). The current environmental change must be measured against the yardstick of past environmental change and environmental reconstruction involves using the techniques described here to ‘read the pages of Earth history’. An alternative method of reconstructing past environments explained here is to ‘postdict’ (make predictions for past changes) environmental conditions using mathematical models. Finally, based on the arguments presented, a ‘blueprint’ for a new physical geography is outlined.

LEARNING OUTCOMES
After reading this chapter, you should understand:

The human domination of the planet
Human impacts on flows in the Earth system
Human impacts on biodiversity
Methods for studying the past, present, and future past Earth system.

SUMMARY

Humans interact with their planetary environment. They affect, and are affected by, environmental change. Therefore, human–environment interactions viewed in the context of the Earth as a system provide a useful focus for physical geography. A novel approach to physical geography stems from regarding humans and the human-altered environment as equal partners with the natural environment.

Two chief facts validate this viewpoint. First, the human species has come to dominate much of the land-surface and in doing so, has radically altered the natural flows and storage of gases and soluble materials in biogeochemical cycles, and altered the flow and storage of sediments in the sedimentary cycle. Perhaps even more significantly, it has transformed the land cover, mainly by turning land over to agricultural and urban use, causing the loss and fragmentation of habitats in the process.

A consequence of these human-induced environmental changes is a substantial loss of biodiversity, with humans being responsible for much species extinction. Much can be gained by viewing the Earth as a global system and new techniques, such as remote sensing, allow the global ecosystem to be measured, monitored and mapped. High-powered computers enable the global ecosystem to be simulated in a manner scarcely imaginable in the 1970s, while past environmental changes provide a historical perspective for the current changes. Environments in the past can be reconstructed using geochemical, physical, biological, and historical and documentary evidence. They may also be studied using mathematical models of present environments applied to past conditions. A ‘blueprint’ for a new physical geography is presented that takes a human perspective.

QUESTIONS

1. To what extent have humans come to     dominate the Earth's surface?

4. Describe the advances in monitoring and
    mapping the environment made since     the 1940s.

2. How important are humans as agents of
    erosion?
5. Describe the techniques used to     reconstruct past environments.

3. Explain how humans alter flows and     stores in biogeochemical cycles.
6. Is a global approach to physical    geography justified?