Week 2: Introduction To Global Environment

Question 1

System

Answer 1

a collection of interdependent parts enclosed within a defined boundary

Question 2

Spheres

Answer 2

Biosphere: Earth
Hydrosphere: Water
Lithosphere: Rock
Atmosphere: Air

Question 2

Earth system: atmosphere:

Answer 2

• 21% oxygen, 78% nitrogen + trace gases (link to biosphere) all animals need for breathing
• 5*1018kg (75% within lowest 11 km)
• Troposphere: weather, 98% of water vapour (link to hydrosphere)
• Stratosphere: ozone layer
• Controlling global energy balance & climate (greenhouse effect from water vapour, C02, …)
• Atmospheric circulation: weather, redistribution of energy, hydrological cycle
• Air pollution

Question 3

EARTH SYSTEM- HYDROSPHERE (CRYROSPHERE)

Answer 3

• Liquid solid and gas
• 1.4*1021 kg (0.023% of total Earth’s mass)
• Oceans contain 97% of Earth’s water and cover 75% of the Earth’s surface (361*106 km2)
• H2O occurs in all three states (solid, liquid, gas)
• 2*1016 kg as water vapour in atmosphere
• Vital for the development of life
• Ocean circulation: distribution of energy, huge storage capacity, climate impact
• Cryosphere (approx. 2%): climate feedbacks (e.g., albedo), sea level rise, reservoirs of freshwater
• Available surface freshwater (approx. 0.01%) direct use to humans (clean freshwater is a precious resource)

Question 4

EARTH SYSTEM- LITHOSPHERE (PEDOSPHERE)

Answer 4

• Foundation of the entire ecosystem we have on earth–source of all raw materials
• Crust and portion of upper mantle
• Plate tectonics: earthquakes and volcanism
• Foundation of entire earth system
• Source of all raw materials
• Pedosphere: outermost layer of the Earth that is composed of soil and subject to soil formation process.  platform for food production
• Processes are relatively slow and changes occur only over long periods of time (e.g., redistribution of geologic material (sources and sinks); formation of fossil fuels)

Question 5

EARTH SYSTEM- BIOSPHERE (ANTHROPROPHERE)

Answer 5

• Sum of all biological activity
• Photosynthesis converts solar energy into organic
  material – all organic material on the earth was produced by photosynthesis at one point
• Driver of carbon cycle
• Created and maintains oxygen-rich atmosphere
• Chemical weathering
• Anthroposphere:
  Part of the environment that is made or modified by humans for use in human activities and human habitats

Question 6

EARTH SYSTEM AND SPHERES

Answer 6

• Closed system
  
  • All matter that is available for the activities and processes on earth has been here since its formation and is constantly recycled
  • Energy is exchanged with the environment, but matter is not
  • The primary input to the earths system is the solar radiation from the sun (340 joules/second)
  • Resources are finite
    Energy is exchanged with the outside environment, while matter is not Example: Earth
• Open system
  Both energy and matter are exchanged with the outside environment. Example: Any of the Earth’s spheres

Question 7

CONCLUSIONS
* The Earth is a complex system that is composed of four main subsystems or spheres.
* The four main spheres are the atmosphere, hydrosphere, lithosphere and biosphere.
* The Earth as a whole is a closed system only exchanges energy with its environment.
* The individual spheres are open systems that exchange both energy and matter.