1
© Springer Nature Switzerland AG 2020
A. Kerényi, R. W. McIntosh, Sustainable Development in Changing Complex Earth Systems,
Sustainable Development Goals Series, https://doi.org/10.1007/978-3-030-21645-0_1
Introduction
1
1.1
Qualitative Changes
in the Evolution of the Earth
Planet Earth came into existence almost 4.6 billion years ago and survived numerous changes in
its history. These changes made the global Earth
system more and more complex, i.e. the system
developed. This development can be divided into
three different sections the length of which in
time shows great differences.
Section one, the abiotic system lasted for
almost 1 billion years. (It is not known exactly
when life occurred on Earth but on the basis of
fossils it is known that photosynthesising microorganisms, cyanobacteria lived on Earth as early
as 3.5 billion years ago.) The development of the
abiotic system included a series of physical and
chemical transformations. Most scientists consider chemical changes more important as the
occurrence of more complex compounds resulted
in the appearance of organic molecules that could
become the basis of life. (Presenting the still
unsolved mystery of the origin of life on Earth is
out of the scope of this book but it seems clear
that every constituent of life was available on the
abiotic Earth.) The process resulting in compounds with complex composition and structure
involving organic carbon formed out of simple
inorganic molecules is called chemical
evolution.
With the occurrence of living beings the second, very lengthy period of the development of
our planet started and could be called the living
Earth. This period is characterised by not only
the evolution of life but also the transformation
of the environment in the process of which living
creatures took an active part. Metabolism processes changed primarily the composition of the
atmosphere. The ancient reductive atmosphere
almost completely void of free oxygen molecules
was transformed into an oxidant atmosphere as a
result of the metabolism of photosynthesising
living creatures over billions of years. As the
quantity of atmospheric oxygen increased the
ozone shield was formed making the survival of
life outside the seas and its spreading all over the
dry lands possible since the ozone layer absorbs
the part of ultraviolet radiation, which is most
dangerous to life. (Marine life before was protected from UV radiation by the water body.)
Increasing atmospheric oxygen also enabled the
development of respiration that provided much
better energy supply for living organisms than
fermentation resulting in the evolvement of
higher living creatures.
With the contribution of life, productive soil
was formed on dry lands resulting in favourable
conditions for the nutrient supply of plants. Life
was differentiated to an increasing number of
species. Occurrence and disappearance of species over the history of the Earth meant not
always the dominance of the previous process.
Conditions on Earth were not always preferable
for life. Since the start of the Palaeozoic (570
million years ago) five phases of extinction have
© Springer Nature Switzerland AG 2020
A. Kerényi, R. W. McIntosh, Sustainable Development in Changing Complex Earth Systems,
Sustainable Development Goals Series, https://doi.org/10.1007/978-3-030-21645-0_1
Introduction
1
1.1
Qualitative Changes
in the Evolution of the Earth
Planet Earth came into existence almost 4.6 billion years ago and survived numerous changes in
its history. These changes made the global Earth
system more and more complex, i.e. the system
developed. This development can be divided into
three different sections the length of which in
time shows great differences.
Section one, the abiotic system lasted for
almost 1 billion years. (It is not known exactly
when life occurred on Earth but on the basis of
fossils it is known that photosynthesising microorganisms, cyanobacteria lived on Earth as early
as 3.5 billion years ago.) The development of the
abiotic system included a series of physical and
chemical transformations. Most scientists consider chemical changes more important as the
occurrence of more complex compounds resulted
in the appearance of organic molecules that could
become the basis of life. (Presenting the still
unsolved mystery of the origin of life on Earth is
out of the scope of this book but it seems clear
that every constituent of life was available on the
abiotic Earth.) The process resulting in compounds with complex composition and structure
involving organic carbon formed out of simple
inorganic molecules is called chemical
evolution.
With the occurrence of living beings the second, very lengthy period of the development of
our planet started and could be called the living
Earth. This period is characterised by not only
the evolution of life but also the transformation
of the environment in the process of which living
creatures took an active part. Metabolism processes changed primarily the composition of the
atmosphere. The ancient reductive atmosphere
almost completely void of free oxygen molecules
was transformed into an oxidant atmosphere as a
result of the metabolism of photosynthesising
living creatures over billions of years. As the
quantity of atmospheric oxygen increased the
ozone shield was formed making the survival of
life outside the seas and its spreading all over the
dry lands possible since the ozone layer absorbs
the part of ultraviolet radiation, which is most
dangerous to life. (Marine life before was protected from UV radiation by the water body.)
Increasing atmospheric oxygen also enabled the
development of respiration that provided much
better energy supply for living organisms than
fermentation resulting in the evolvement of
higher living creatures.
With the contribution of life, productive soil
was formed on dry lands resulting in favourable
conditions for the nutrient supply of plants. Life
was differentiated to an increasing number of
species. Occurrence and disappearance of species over the history of the Earth meant not
always the dominance of the previous process.
Conditions on Earth were not always preferable
for life. Since the start of the Palaeozoic (570
million years ago) five phases of extinction have