Plants Theory (recent):

  • Given by University research team
  • Global cooling was caused by reduction of carbon in the atmosphere due to the first appearance of plants (photosynthesis)
  • Less greenhouse gas (carbon) to prevent escape of infrared radiation which leads to cooler temperatures (less heat trapped)
  • Plants (ex. moss) extract calcium, magnesium, phosphorus and iron which weathers the land
  • Weathering triggers more carbonate rocks and carbon burial bodies of water

Continental Drift Theory:

  • Given by A. Wegner in 1922ice-age
  • Continents move on the surface of the globe
  • Movements of the poles
  • Supports developments of ice sheets

Astronomic theories

1.) A change in the eccentricity of the earth’s orbit

  • Earth’s orbit is altered (made more/less eccentric) by gravity of other planets or special bodies
  • Causes temperature on earth to be colder or warmer (further or closer from the sun)
  • Alters the distribution of solar radiation
  • Cold can contribute to positive feedback loop of ice (Aledo)

2.) The earth’s tilt changes

  • Earth’s tilt causes more extreme temperatures in summer and winter
  • As tilt gets larger, so do the extremities in temperature
  • Tilt changes about every 40,000 years

3.) The earth’s wobble (precession)

  • Earth has a precession cycle of about 23,000 years
  • Affects the climate temperatures in various parts of the world as the wobble changes where the axis is pointing (changes where there’s summer and winter)
  • When earth is in a position where the poles get even colder temperatures, it makes the entire earth colder (possible cause of ice ages)


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