TOPIC 2 - Into to Global Environment

Question 1

lithosphere

Answer 1

• Crust and portion of upper mantle
• Plate tectonics: earthquakes and volcanism
• Foundations of entire earth system
• Source of all raw materials
• Contains the pedosphere: outermost layer of the Earth that
• composed of soil and subject to soil
  formation process -> platform for food production.
• Processes are slow and change occurs over long periods of time (e.g., redistribu3on of geologic
  material (sources and sinks); formation of fossil fuels).

Question 2

Atmosphere

Answer 2

• 21% oxygen, 78 % nitrogen and some trace gases that link to the biosphere. Mass of 5x10^18 kg (7%
  within lowest 11 km).
• Atmosphere contains the troposphere which controls weather and holds 98% of water vapour (linked
  to hydrosphere). Also has the stratosphere containing the protec3ve ozone layer.
• Controls global energy balance and climate (greenhouse effect from H2O, CO2 etc.).
• Atmospheric circula3on: weather, redistribu3on of energy, hydrologic cycle.
• Air pollu3on.

Question 3

Hydrosphere

Answer 3

• 1.4x10^21 kg (0.023% of total Earth mass).
• Includes all of Earths H2O. Oceans contain 97% of earths water and cover 75% of earths surface. § H2O occurs in all three states.
• 2x10^16 kg as water vapour in atmosphere.
• Vital for development of life
• Ocean circula3on: distribu3on of energy, huge storage capacity, climate impact.
• Cryosphere (approximately 2%): aids in climate feedbacks, sea level rise, reservoirs of freshwater. § Only 0.01% of earths water is available surface freshwater.

Question 4

Biosphere

Answer 4

• Represents all biological ac3vity on the planet.
• Photosynthesis converts solar energy into organic material.
• Drives the 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
  ac3vi3es and human habitats.

Question 5

explain how spheres interact via cycles that consist of reservoirs, fluxes, inputs, and outputs.

Answer 5

• Pathway that describes how a substance moves through various components of the earth system.
• Also known as biogeochemical cycles, moving through different spheres (ex. Nitrogen, water, rock).
• Cycles consist of reservoirs (holding sites) and fluxes (movements between reservoirs). Also need an energy source to fuel the movement processes.

Question 6

understand how a perturbation can change the state of a system.

Answer 6

• Linear: the magnitude of the response is propor3onate to the perturba3on. (very rare, as is only when one change is present/pin-pointed).
• Feedback loops: the response to a disturbance includes an effect on the magnitude of the perturba3on.
• Posi3ve loops increase response to a disturbance (dis3brance is enhanced) and nega3ve loops
  decrease response to a disturbance.
• Ex: the rela3onship between sea ice and temperature.

Question 7

list examples of perturbations (both natural and human caused) and system responses at different spatial and temporal scales.

Answer 7

o Landslides
o Changes earths orbit
o Pollu3on
o Changes in CO2 concentra3on o Agriculture
o Economic system
* Regardless of cause, the cycle must adjust/adapt to the changes by changing fluxes/resevoirs, cycle speed etc.

Question 8

know that most global change issues discussed in this course involve multiple spheres.

Answer 8

• The spheres and cycles define the structure of the Earth system and determines how it responds to change.
• Cycles can be constant or cyclical.

Question 9

System: closed system (e.g., Earth) versus open system (e.g., individual spheres)

Answer 9

• Closed system: energy is exchanged with the outside environment, while matter is not (Earth).
• Open system: Both energy and maeer are exchanged with the outside environment (any of earths spheres).