|
|
Chapter 2
|
|||
|
|
IntroductionPlanet Earth, unique in the solar system, has been able to harbor life since more than 4 billion years. All life depends on energy. On Earth almost all energy comes, originally, from the sun. Life also depends on water, on Earth 70% of the surface is water the rest is land. On land the bedrock is usually covered by soil. A protecting atmosphere is also important. Earth has a radius of about 6,400 km on top of that comes the atmosphere. The thin slice were life is able to exist is called the ecosphere. The life forms interfere with the physical processes of the planet and are part of the different components of the system. Bio-geo-chemical cycles of material flows have evolved through time. Man has intervened in these large global processes and caused harmful results. It is possible to define conditions that humankind has to fulfill to not disturb the system of our planet.
Authors of this chapter are: Lars Rydén |
|||
|
|
||||
|---|---|---|---|---|
