The Resources of the Earth - Thanatia: The Destiny of the Earth's Mineral Resources - page 133

Chapter6
The Resources of the Earth
6.1 Introduction
In this chapter, a deeper look at the Earth's components deemed useful to Man is
undertaken. Consequently, a revision of energy and non-energy resources is carried
out. This information will serve in a later chapter for assessing the exergy of the
main resources on Earth. Energy resources have been divided into energy originat-
ing from the solid Earth i.e. nuclear and geothermal; tidal; and that derived from
the sun, including solar, hydroelectricity, wind, biomass and hydrocarbons. After a
general description of each, it shows all of the potentially available resources that
Nature provides, those which could be effectively obtained using technology into
the near future and those which are used today. In addition, mineral resources are
studied, highlighting their abundance and average crustal concentration.
6.2 Natural resources: definition, classification and early
assessments
A natural resource can be defined as any form of matter or energy obtained from
the environment that meets a human need. Therefore water, air, oil, biomass or
minerals are classified as such. Natural resources are frequently categorised as
renewable or non-renewable. The former are defined as those that are regenerated
within a human time scale. Examples include hydro, biomass or solar energy. On
the contrary, the latter can be considered a stock that has a regeneration rate of
zero over a relatively long period as is the case of minerals (Lujula, 2003).
Minerals can be further classified as fuel and non-fuel resources. Fuel resources
are those from which energy can be potentially extracted i.e. coal, oil, natural gas
or uranium. Non-fuel minerals include metals and industrial minerals.
An early assessment of the renewable and non-renewable energy resources on
Earth was undertaken by Hall et al. (1987) and can be seen in Table 6.1.
The degree of knowledge about resources and technological development has
improved notably since the eighties, when Hall et al. (1987) undertook the first
review and this has led to better estimations of the available resources on Earth.
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