Geoscience Reference
In-Depth Information
that the soil's thickness is about million times smaller or six orders of magnitude
less (10
−6
) than the radius of Earth.
On the other hand, the thickness of a human's skin is a thousand times smaller
than a human's height, or it is by three orders of magnitude smaller (10
−3
). The rela-
tive thickness of the protective layer of the Earth is a thousand times less than that
of humans. In order of magnitude it is 10
−3
. Comparing the relative thickness of a
human's skin to that of the soil, humans are protected much better by their skin than
the Earth is protected by its thin soil layer. When we consider a broad number of
continental mammals of all sizes, we learn that the relative thickness of their skin is
somewhat smaller than the human skin but never falls below a relative magnitude of
100. With the relative soil thickness of Earth being substantially smaller than the
relative skin thicknesses of both humans and mammals, we expect that the soil pro-
tects the Earth less than the skin protects either humans or mammals. We must take
into consideration this expectation of vulnerability when we start discussing the
birth, longevity, and death of soils and realize that even a very thin soil is still an
unconditional requirement for life on Earth. Regardless of the thickness and conti-
nuity of the Earth's topsoil, many geographic locations are not acceptable or condu-
cive for human life owing to local environmental conditions causing extremely
thinned or even destroyed skin. We should always remember that the skin of a mam-
mal is protecting just that particular species, while the skin of the Earth is ensuring
all forms of life on all continents of our planet.
Our opponents who may not consider the necessity of the myriad of biological
processes contributing to the health and safety of the Earth's skin could raise objec-
tions against our relative thickness estimates of soils. Merely focusing on physical
processes occurring within the transition from the Earth's rocks to the atmosphere
above its surface, they may well limit their thoughts to transport between solid and
gaseous states in the absence of biological processes. If we accept their statement
that the rough average thickness of the Earth's solid crust is about kilometers, we
calculate that the actual measured soil thickness of 1 m is more than hundred thou-
sand times smaller than the solid Earth's crust (i.e., in order of magnitude 10
−5
).
Compared to human's skin thickness, it is hundred times less. Considering the
mammals' skin, the soil is between ten times and hundred times less than the mam-
mals' skin.
Let us fi rst simply assume that there is a linear indirect relationship between the
thickness of the skin and its vulnerability. Then the extremely fi ne thickness of the
Earth's skin - the soil - would mean that the most important Earth's property would
be very imperiled if the soil characteristics strongly and abruptly changed. It remains
now to show what we consider is the most important property of the Earth. Being
egoistic members of a biological order and desiring the sustainability and continued
development of positive life conditions for ourselves, we designate the most impor-
tant property on the prerequisite that it is subject to evolutionary principles. Any
abrupt change in the characteristics of the Earth's skin should therefore be avoided.
Accepting this principle, soil has a decisive, ever-present infl uence upon all forms
of life activity on Earth. It is a diverse global system of sustainable yet ever-changing
local and regional environments that support and delineate micro- and macroorganisms
