2A.1 Key Words

Question 1

Greenhouse Earth

Answer 1

Little or no ice cover

Question 2

Icehouse earth

Answer 2

High average glacier ice cover

Question 3

Albedo

Answer 3

The reflective coefficient of a surface i.e., the proportion of incident radiation reflected by a surface (very high in the case of snow or ice).

Question 4

Glacial

Answer 4

Cold, icehouse periods

Question 5

Interglacial

Answer 5

Warner periods similar to present.

Question 6

Pleistocene Epoch

Answer 6

A geological period from around 2.58 MYA to 11,700 YA, the early part of the Quaternary which includes the most recent ice age.

Question 7

Stadial

Answer 7

Short-lived colder periods within a major glacial, associated with ice advance.

Question 8

Interstadial

Answer 8

Short-lived warmer periods within a major glacial, associated with ice retreat.

Question 9

Thermohaline Circulation (THC)

Answer 9

Global system of ocean currents. Driven by differences in temperature (thermo) and salinity (haline).

Question 10

What has the dominant tyep of Earth been?

Answer 10

Greenhouse Earth.

Question 11

Icehouse ages in geological time.

Answer 11

Huronian = 2.3-2.2 billion ya
Cryogenia = 720-635 mya
Late Ordovician = 445.6 -443.7 mya
LAte Devonian to early Carboniferous = 361-349 mya
Permo-Carboniferous = 326-267 mya
Pleistocene = 34 mya - present

Question 12

Pleistocene epoch

Answer 12

2.58 mya to 11,700 ya (start of Holocene).
Within quaternary period
Most recent ice house

Question 13

Last glacial maximum

Answer 13

Devensian - 20,000 ya

Question 14

Loch Lomond Stadial (Younger Dryas)

Answer 14

Drainage of huge pro-glacial lake disrupted THC, cutting off poleward heat transport from the Gulf Stream.

temperatures fluctuated, at least 3 pulses of ice advance and retreat between 26,000 and 10,000 ya.
Ice sheets retreating around 18,000 ya, rapid deglaciation by 15,000 ya.

Question 15

Evidence of Loch Lomond Stadial

Answer 15

Scotland - plateau ice fields
Wales - cirque glaciation (Snowdonia)
England - ice fields and valley glaciers (Lake District)
Ice dammed lakes - parallel roads of Glen Roy.

Question 16

Little Ice Age

Answer 16

Period of cooling particularly pronounce in North Atlantic region.
1550-1850.
Cooler conditions by 1-2 degrees, caused colder winters (frozen Thames).
Crop failure across Europe.
Varying causes: volcanic activity, decreased levels of solar radiation (sunspot activity).

Question 17

Milankovitch Cycles

Answer 17

Eccentricity (100,000 yrs)
Obliquity (41,000 yrs)
Precession (23,000 yrs)

Question 18

Eccentricity

Answer 18

100,000 yrs
Shape of the Earth’s orbit around the sun.
Alters distance travelled by short-wave radiation.

Question 19

Obliquity

Answer 19

Axial tilt
41,000 yrs
21.5 to 24.5 degrees
Responsible for seasonal differences.

Question 20

Precession

Answer 20

Wobble of the Earth on its axis.
23,000 yrs
Makes seasonal contrasts more extreme in one hemisphere and less extreme in the other.

Question 21

Variations in solar output

Answer 21

Sunspots - flares on suns surface.
High level of sunspots = increased radiation and average temperature.
Temperature change between +0.5 and -0.5 degrees globally.

Question 22

Volcanic eruptions

Answer 22

Need to be large and explosive to change Earth’s climate. Ash and gas will reflect solar energy back into space cooling the planet.

1815 - Tambora volcano in Indonesia erupted (largest in history) and cooling temperatures caused no summer and 20,000 deaths from crop failure. Effects lasted 4-5 years.

Question 23

Positive feedback loop

Answer 23

Starts one way and ends the same way.

Question 23

Negative feedback loop

Answer 23

Starts one way but ends the other way.

Question 24

Positive feedback loop - climate change

Answer 24

Snow and ice cover, Albedo effect reflects energy back into space causing cooling and more ice cover.

Melting snow and ice due to CO2 causes decrease in Albedo effect, permafrost melts releasing methane causing more calving of ice sheets. Less ice cover = less albedo effect accelerating warming.

Question 25

Negative feedback loop - climate change

Answer 25

Increased warming - more evaporation - cloudier skies reflects more solar energy cooing the Earth, ‘global dimming’.

Warmer Arctic waters disrupts THC, less warm water in Gulf Stream drawn north leading to cooling in Europe.