Climate

Question 1

What changes is the cryoshepre a driver of?

Answer 1

• mid-Pleistocene transition (from 41 kyr- to 100 kyr-dominated climatic variations)
• large, sub-orbital scale climatic oscillations
• fast switches in climate

Question 2

What broad trends happens in the cenozoic?

Answer 2

Cenozoic
• global cooling
• falling sea-level
• rising biodiversity

Question 3

Tectonics

Answer 3

Affect oceanic and atmospheric circulation. Impact distribution of surface albedo.

But position of continents at start of quaternary is similar to present day. Little impact

Question 4

Factors affecting atmospheric composition

Answer 4

Volcanic eruptions
Biochemical evolution (increase in oxygen)
Greenhouse gases

Question 5

Definition of orbital cycles

Answer 5

temporal changes in insolation that are
astronomically driven

Question 6

What are the three types of orbital cycles?

Answer 6

Eccentricity/shape
Obliquity/tilt
Precession/wobble

Question 7

What is eccentricity?

Answer 7

Whether the shape of orbit is circular or elliptical

Every 100kyr. Same as glacial cycles.

Only 0.3% change in radiation at extremes. Which is about 0.3 °c.

Doesn’t explain cooling of 5-10°c required for glacials.

Question 8

What is obliquity?

Answer 8

Tilt.

From 21°c to 25°c

Every 40kyr.

Affects seasonal contrast. Not overall insulation/temperature.

Question 9

What is precession?

Answer 9

Wobble.

Season for each hemisphere experienced when earth at perihelion (closest to sun).

Currently, northern hemisphere has winter at perihelion.

May explain younger dryas. When northern had summer at perihelion.