wk 2: earth systems

earth system

• a collection of interdependent parts enclosed within a defined boundary

• input (energy or matter )from external environment to the complex system → fuels processes within system → system produces outputs that flow back to environment

earth system - spheres

• one way of looking at the world is to divide into 4 subsystems —spheres

• air, water, land, and all living things on earth

• atmosphere (air)

• hydrosphere (water)

• lithosphere (land)

• biosphere (all living things)

atmosphere

• thin layer of air that covers the air

• 21% oxygen, 78% nitrogen + trace gases (water vapour, Co2, links it to biosphere)

• troposphere: majority of the mass of the atmosphere, lowest 11 km of the atmosphere, where all the weather is happening

• stratosphere: ozone layer, above the troposphere,

• atmosphere is critical to earth system—controls the global energy balance, determines the climate we experience

  • atmosphere circulation: weather, redistribution of energy, hydrological cycle

• air pollution

earth system hydrosphere

• main water bodies on earth system, oceans, lakes, rivers, icecaps

• components are also critical to life

• oceans contain 97% of earths water, cover 75% of surface

• oceans can store huge amounts of energy (bc amount of water)

  • ocean currents redistribute energy (wind → atmosphere)

• ocean circulation: distribution of energy, huge storage capacity, climate impact

• cryosphere (approx 2%): critical for climate feedbacks, (melting ice caps → sea level rise), reservoirs of freshwater stored in ice caps + glaciers

• available surface clean freshwater (approx 0.01%)

earth system - lithosphere

• earths crust + upper parts of mantle

• tectonic plates: moving over central magma, responsible for earthquakes, volcanic activity (when split apart)

• 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)

earth system - biosphere

• sum of all biological activity

• photosynthesis coverts solar energy into organic material

• 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

energy

• what is fuelling all the activity that goes on earth ?

• primary energy input into sun: solar radiation from sun

• earth does not receive energy evenly, weather systems + oceans currents move the energy from areas of higher inputs (equators) to areas of lower inputs (poles)

• if planet absorbed all this energy, planet would quickly heat up and explode

  • means that the earth must also be emitting energy → balance btw input and output of energy

  • climate change one cause is the imbalance of this energy exchange

earth: closed system - matter

• use energy to form matter

• earth doesn’t exchange matter with its environment

• all of the materials that are available for activities and processes have been here since the formation of the earth

• what happens is the matter gets constantly recycled

• refer to the earth as a closed system, energy is exchanged with the environment (space) but not matter

• physical resources of the planet are finite

energy and matter

• energy and matter flows freely among all the sphere when they interact with each other

closed + open system

• closed system

  • energy is exchanged with the outside environment, while matter is not e.g. earth

• open system

  • both energy and matter are exchanged with the outside environment e.g. any of earths spheres