FInal Study Guide 13 Flashcards
Long Term Climate Variation
What is the carbon cycle?
Carbon begins in the atmosphere in some form. It can be taken in by plants in the form of CO2 in order to perform photosynthesis. When this organic matter dies and is buried. This waste fossilizes and its carbon can be burned for energy. There are many different ways to release carbon from organic matter. Burning wood is another example. Release this carbon puts it into the atmosphere, restarting the cycle.
Why does the carbon cycle act as a thermostat for Earth climate?
- The carbon cycle acts as a thermostat because it maintains Earths temperature and creates a thermal blanket. The carbon cycle is only possible on Earth due to plate tectonics.
- Self Regulating system (negative feedback)
- As CO2 increases, temperature increases
- As temperature increases, rate of weathering increases
- As weathering increases, Levels of CO2 decrease
- Weathering reaction important, more efficient at higher temperatures
What is the faint sun problem?
- We hypothesize the sun is much larger and brighter now, so in early Earth when the sun was fainter, why wasn’t the Earth frozen over? There are two hypotheses.
> The first is that there could have been a greenhouse effect that was substantially larger causing more erosion and the release of CO2.
> The second suggests (the change in terms of albedo) there is more whiter stuff now that reflects the sunlight so that even though the sun burns hotter and brighter now, the Earth today is reflecting more back.
Ice record
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Temperature proxy
above
Isotope
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Deuterium
- one of two stable isotopes of Hydrogen
- natural abundance in oceans
Ice Age
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Natural Climate Change
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Eocene Optimum
little to no ice was present on Earth with a smaller difference in temperature from the equator to the poles
Meteorite forcing
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Carbon cycle
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Tectonic forcing
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Volcanism
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Pleistocene Ice Age
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Interglacial
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Holocene Maximum
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Faint sun
- Sun has changed its luminosity over time (amount of radiation that goes out)
- Star burns heavier and heavier fuels over time increased radiation
- Even though the Sun was about 30% dimmer than it is now, temperature on Earth has been more or less stable
- It should have been so much colder because the sun was so much fainter due to carbon cycle
Luminosity
measure of brightness, can be measure in terms of radiant power, i.e solar luminosity
Albedo
Reflectivity of a surface, typically that of a planet or moon. Like the snow that reflects the sunlight to prevent the surface of the earth from overheating.
Continental Formation
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Organic carbon
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Carbonic acid
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