Explain how volcanic eruptions contribute to variations in ...

[cnetterville]

Explain how volcanic eruptions contribute to variations in Earth's temperature through geologic time and on historic time frames.
 
  What will be an ideal response?

Question 2

Explain how the amount of solar energy received at the top of Earth's atmosphere varies on both the short term (decade and century) and the long term (thousands to hundreds of thousands of years).
 
  What will be an ideal response?

[Jevvish]

Answer to Question 1

Volcanoes emit gases to the atmosphere. Emitted carbon dioxide contributes to warming. Emitted sulfurous aerosols contribute to cooling. On historic time frames, the focus is on the larger volume of sulfurous aerosols compared to carbon dioxide. During historic times, therefore, highly explosive volcanic eruptions have typically been followed by unusually cool temperatures. On geologic time scales of millions or tens of millions of year, however, long periods of greater volcanic activity may also contribute significant amounts of carbon dioxide. During times when there are longer mid-ocean ridges or when sea-floor spreading rates are unusually high, there should also be more carbon dioxide released to the atmosphere; this may account for both warmer temperatures and higher carbon dioxide levels at times in the geologic past.

Answer to Question 2

Satellite measurements show that solar radiation varies with the 11-year sunspot cycle. In addition, there are longer trends of increasing or decreasing radiation, on the scale of many decades to centuries, which are interpreted from theoretical calculations and consistent with the limited period of satellite data collection. On the longer time frames, the Milankovitch cycles that describe variations in the tilt and wobble of Earth's rotation axis and variations in the shape of Earth's orbit around the Sun, also cause changes in the amount of solar radiation reaching Earth.