2A.1 causes of longer and shorter climate which have led to icehouse - greenhouse conditions.

Question 1

Characteristics of the Pleistocene and Holocene.

Answer 1

Regarded as the single ice age, nut multiple periods of glacial and also inter Glacial’s. Began from the beginning of the quaternary to about 11,500 years. Shorter term changes have taken place more recently during the Holocene period.

Pleistocene - was a geological period that spans from 2.6 million to 12,000 years ago. Whereas the Holocene is a geological period that goes from 12,000 years ago to the present day, although scientists believe we are in a new geological age called the Anthropocene, where humans are the leading cause of environmental change.

Question 2

Milankovitch cycles (long-term interglacial periods) - Eccentricity (stretch)

Answer 2

-Changes from more elliptical to more circular and back again over a period of 100,000 so it changes amount of radiation the Earth receives from the sun.

Question 3

Milankovitch cycles (long-term interglacial periods) - Axal tilt

Answer 3

-varies from 21.8 to 24.4 over a 41,000 years. Changes intensity of radiation received at the poles and therefore the greater the tilt the bigger the difference between summer and winter.

Question 4

Milankovitch cycles (long-term interglacial periods) - Wobble

Answer 4

Wobble alters the distance between the sun and Earth over a 21,000 year period causing seasons in different orbital paths.

Question 5

Sunspot activity -

Answer 5

• Temporary spots on the the Earth’s photosphere and increase the amount of solar radiation towards the Earth
• Happen on a range of cycle the lowest being 11 years
• Increase net radiation by 0.1%

Question 6

Volcanic activity -

Answer 6

• Emit ash, carbon dioxide and sulphur in the atmosphere
  -Act as a buffer between the suns rays and the Earth’s surface and reduce solar radiation.
  Example is the eruption of Krakatoa in Indonesia, therefore releases ash cloud and volcanic matter and affected the Earth’s climate for 3 years, worldwide temperatures dropped by 1.2 degrees and world wide temperatures weren’t back to normal until 5 years after the explosion.

Question 7

Icehouse and Greenhouse times -

Answer 7

‘Icehouse’ describes a time when ice cover was present across large areas of the globe. ‘Greenhouse’ describes when the climate was much warmer and the land was largely ice-free.

Question 8

Loch Lomond Stadial (Pleistocene) - Described as shorter term events

Answer 8

Happened between 12,700 and 11,500 years ago, so can be described as being during the Pleistocene period, in this time period glaciers re-grew in the Scottish highlands. (Upland Britain).

The Pleistocene saw over 20 major fluctuations of interglacial and glacial periods. Glacial periods - colder and extensive ice cover. Interglacial periods- Interglacials with warmer temperatures and to be about 5-6 degrees warmer.

Question 9

The little Ice Age (Holocene) - described as shorter term events

Answer 9

From 15th to 18th Centuries AD, temperatures were 1 degree cooler than at the present and some British rivers froze. (The Thames)