Geography Reference
In-Depth Information
from the rest of the biosphere, however, is the conscious ability
to create their own cultural and technological environments.
It is therefore possible to recognize a sphere of human mental
activity, which has been termed the 'noösphere'. This is shown
in Figure 4(B) alongside the natural geo-ecosphere. The overlap
between these two spheres represents the human-modifi ed
geo-ecosphere, or anthroposphere. Herein lies an essential
connection between physical and human geography, and it is in
this sense at least that the natural environment can be regarded as
the physical basis of geography.
As human impacts on the natural environment increase
inexorably, it is more diffi cult to differentiate a natural
geo-ecosphere from the anthroposphere. Most of the Earth's
surface and its component spheres are impacted by both natural
and human disturbances of various types. Agriculture now
regularly affects around 45% of the Earth's terrestrial surface,
forestry some 10%, transportation 5%, urban development 3%,
and mineral extraction 1%. Even military activities affect, or have
recently affected, an appreciable area, ranging from 1% of the USA
to 40% of Vietnam. This does not mean either that
all
of physical
geography is concerned with human environmental impacts,
or that there is a physical environmental basis to
all
of human
geography, but that the nature of the interaction must always be
considered.
The early development of physical geography
Of the early founders, the most eminent proponent of physical
geography as a scientifi c entity was undoubtedly the German
polymath Alexander von Humboldt. On his many travels, he
combined observations with measurements of temperature,
pressure, and the Earth's magnetic fi eld, and made generalizations
about the geographical distribution of vegetation, global-scale
patterns of temperature (depicted by isotherms on maps), the
ways in which temperature falls and vegetation varies with
