Environmental change during the quaternary

Question 1

What is parihelion?

Answer 1

The point in the orbital path of a planet that is CLOSEST TO the sun (under eccentricity)

Question 2

What is aphelion?

Answer 2

The point in the orbital path of a planet that is FURTHEST FROM the sun (under eccentricity)

Question 3

What is a good paper for marine ice sheet instability?

Answer 3

Ruckert et al., 2017

Question 4

How do tipping points work?

Answer 4

• Once a threshold is exceeded
• Hysteresis loops
• Non-linear response, accelerating
• System enters a new state and equilibria

Question 5

Who has suggested that the closure of the central American seaway 3.2Ma is associated with N Hemisphere glaciation?

Answer 5

• O’Dera et al., 2016 - because of intensified gulf stream, introducing warm water and moisture to NH pole
• Haug and Tiedemann, 1998 moisture brings precipitation, which in turn decreases salinity of sea water = more sea ice

Question 6

What is an interesting theory for a driver of the Mid Pleistocene Transition?

Answer 6

Stochastic (chaotic) forcing (Maasch and Saltzman, 1990)

Question 7

What is regolith?

Answer 7

• Soil that has been intensely weathered found beneath ice sheets
• Glacial erosion repeatedly, regolith increases friction, so no regolith = faster + larger ice sheet growth

(Clark et al., 1998)

Question 8

Why is dust important for the climate system?

Answer 8

Dust-albedo feedback

• Stadial (glacial) = more dust (less humidity and moisture)
• Penetration of SW incoming radiation is reduced through scattering
• More cooling (0.42-0.7K)

(Yue, et al., 2011)

Question 9

Who has suggested that glacial ablation has increased magma production?

Answer 9

Huybers and Langmuir, 2009; 2017 - changes CO2 composition
Linked to 41K -> 100K G/IG cycles and MP transition

Only modelled

Question 10

Why is understanding rapid climatic changes during the quaternary important?

Answer 10

• Current climatic changes could be of relevance

- Thresholds for non-linear tipping-point climate forcing

Question 11

What are Dansgaard-Oeschger events?

Answer 11

About 20-25 abrupt transitions from stadial to interstadial conditions(/states)

Linked to CO2, CH4 and AMOC

Question 12

What does AMOC stand for?

Answer 12

Atlantic Meridional Overturning Circulation

Question 13

What is the difference between eccentricity, obliquity and precession?

Answer 13

Eccentricity = shape of orbit 
Obliquity = tilt of axis
Precession = Wobble of axis and orbit

Question 14

Where are the impacts of obliquity most noticable?

Answer 14

At high latitudes because of the extent of axal tilt

Question 15

Why are NH summers important to Milankovitch theory?

Answer 15

• More land surface currently
• Cooler summers = more ice growth (because of less ablation)
• Cold summers require low obliquity, high eccentricity and a summer solstice at aphelion

Question 16

Why are papers showing possible explanation for a specific paleoclimatic event sometimes unreliable?

Answer 16

Selection bias and “cherry picking” to ensure explanations which match proxy records best are used (eg Walker, et al., 2018 for the 8.2 Ka event)

Question 17

When did the mid-Pleistocene transition occur?

Answer 17

1.25-0.7 MA CHECK