Earth system

earth system

Have you heard this term?

The Earth we live on is a complex system of interacting physical, chemical and biological processes. The Earth system can be understood as a set of interlinking and interacting “spheres”. The atmosphere, hydrosphere, biosphere and geosphere (or lithosphere) form the simplest collection, though some would add the cryosphere as a special element dealing with polar regions and processes, and others would add the anthroposphere emphasizing human dimensions and impact on the planet. [1] This system includes the planet’s many natural cycles (e.g. carbon, water, nitrogen, oxygen, phosphorus, sulphur etc.) that support life. [2]

  • The atmosphere extends up from the Earth surface for several hundred kilometers. The lowest part is home to clouds and weather.
  • The biosphere is all living things, from single-celled bacteria to plants and animals.
  • The geosphere (or lithosphere)includes all minerals, rocks, molten rock, sediments, and soils (although there are important living components to soils as well).
  • The hydrosphere includes the ocean, rivers, lakes, streams, groundwater, water vapor, and even puddles.
  • The cryosphere  is the frozen part of the Earth system and includes snow, glaciers, and sea ice.
  • The anthroposphere is that part of the environment that is made or modified by humans for use in human activities and human habitats. [3]

Missing in this list is the context within which the Earth system operates: the solar system and galaxy beyond (sometimes referred to as the exosphere). The sun is the source of driving energy for the Earth and critical external inputs such as asteroids and comets have altered the Earth system significantly in the past.

Earth system science embraces chemistry, physics, biology, mathematics and applied sciences in transcending disciplinary boundaries to treat the Earth as an integrated system and seeks a deeper understanding of the physical, chemical, biological and human interactions that determine the past, current and future states of the Earth. Earth system science provides a physical basis for understanding the world in which we live and upon which humankind seeks to achieve sustainability. [1]

All of Earth’s spheres are interconnected. In fact, the spheres are so closely connected that a change in one sphere often results in a change in one or more of the other spheres. Earth system science studies the changes that occur within and between spheres both as the cause of and the result of an ‘event’.

easth system

This interaction can be understood by considering the following questions.In  my examples, the ‘event’ is a bushfire:-

1. How may each of the earth’s spheres have caused the event to occur?                          (These are sphere vs. event impacts.sphere 2 event

2. What are the effects of the event on each of the earth’s spheres?                                   (These are the event vs. sphere impacts.)event 2 sphere

3. Earth’s spheres on each of the other spheres?  (These are the sphere to sphere interactions.)  

sphere 2 sphere [4]

NASA says ‘the objective of Earth System Science is to understand how the Earth is changing and the consequences for life on Earth with a focus on enabling prediction and mitigation of undesirable consequences’. [5] Given the concerns that humankind is impacting the Earth’s physical climate, a broader concept of Earth as a system is emerging. This includes societal dimensions and the recognition that humanity plays an ever increasing role in global change. Our social and economic systems are now embedded within the Earth system. In many cases, the human systems are now the main drivers of changes in the Earth system. [1]

 

earth system2[6]

 

 

 

 

 

  1. http://serc.carleton.edu/introgeo/earthsystem/nutshell/index.html
  2. http://www.igbp.net/globalchange/earthsystemdefinitions.4.d8b4c3c12bf3be638a80001040.html
  3. http://www.windows2universe.org/earth/ess1.html
  4. https://texasgeography.files.wordpress.com/2010/09/earthsystemscience.pdf
  5. http://education.gsfc.nasa.gov/ESSSProject/ess_definition.html
  6. http://www.phd-ess.org/
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