M2L3 - Climate Cont.

Question 1

Written or Oral histories

Answer 1

• Either direct or indirect
• Nautical journals recording weather conditions
• Timing of harvest dates
• Oral history of lived experiences

Question 2

Corals

Answer 2

• Use calcium carbonate to build their skeletons
• Complex relationship between temp, light, nutrients
• Growth impacted by pH, salinity
• Also trap oxygen and other elements (can tell us about past environment)

Question 3

Pollen

Answer 3

• Often deposited in sediment records
• Unique shapes to different species of plants
• Can inform what was growing at a certain location
• Used in conjunction with sediment dating

Question 4

Ice cores

Answer 4

• Have snow and ice accumulated across millennia
• Contain dust, air bubbles, isotope signature
• Capture a signal at time of deposition
• Can provide information on many climate variables and volcanic activity

Question 5

Tree ring analysis

Answer 5

• Dendrochronology
• Can provide climate and environmental parameters
• Width of ring represents growth

Question 6

Lake and ocean sediments

Answer 6

• Deposited at different rates, depending on the environment
• Can include pollen, diatoms, other biological records
• Thickness of layers can give info on hydrology and land use

Question 7

Earth’s eccentricity

Answer 7

• Orbit isn’t perfectly circular
• Eccentricity is a measure of the departure from a perfect circle
• Cycle occurs over ~100k years
• Currently at most circular

Question 8

Obliquity

Answer 8

• Measure of change in axis of rotation
• Larger the tilt, the more extreme the seasons are
• 41k year cycle

Question 9

Axial precession

Answer 9

• How close we are to the sun in summer
• 23k year cycle

Question 10

Earth’s climate record

Answer 10

• Lack of data from before 500 million years ago
• Temporal resolution of data gets worse as you go back in time

Question 11

Pleistocene climate

Answer 11

Rhythmic patterns

Question 12

Holocene climate

Answer 12

Stability

Question 13

Milankovitch cycles

Answer 13

• Series of variations in the Earth’s orbit around the sun that cause climate change
• Still ongoing, may explain small amounts of change
• Can’t explain the rapid rate of change seen since industrialisation
• Currently in interglacial period, should be cooling not warming

Question 14

Cretaceous alberta

Answer 14

• 144 to 66 million years ago
• Death and decomposition of plant and marine life
• Bacteria broke down light oil resulting in Bitumen

Question 15

Where did meteor that killed dinosaurs land

Answer 15

Chicxulub crater, mexico

Question 16

How did meteor kill dinosaurs

Answer 16

• Resulted in large amount of sediment and dust mobilising
• Dust blocked solar radiation (sun), changing the climate
• Change in environment
• Rapid change of environment means loss of species (mass extinction)

Question 17

Paleocene-Eocene thermal maximum (PETM)

Answer 17

• Occurred approximately 56 million years ago
• Period of rapid warming (5-8ºC over 200k years)
• Large amounts of volcanic activity
• Dramatic change in species and sediments around the world
• Acidification of oceans

Question 18

Ice ages

Answer 18

• Period when glaciers are present (opposed to greenhouse periods when no glaciers present)
• Long and cold periods of alternating glacial and interglacial periods
• At least 5 ice ages in history

Question 19

Interglacial

Answer 19

Period between ice ages

Question 20

Current ice age period

Answer 20

Interglacial period within the Quaternary Ice age

Question 21

The last glaciation

Answer 21

• Ice sheets over 3km thick sculpted much of canada
• Sea level 120m lower (continental shelves exposed)
• Land bridge to Asia

Question 22

End of the last glaciation

Answer 22

• Ice sheets retreat producing lots of water
• Glacial lakes form then drain
• Water drains to the oceans
• Sea level rises to current levels

Question 23

Electromagnetic radiation types (from long to short wavelength)

Answer 23

• Radio
• Microwaves
• Infrared
• Visible light
• UV
• X-rays
• Gamma rays

Question 24

Incoming solar radiation

Answer 24

• 29% reflected
• 48% absorbed at the surface
• 23% absorbed by the atmosphere

Question 25

Planck's law

Answer 25

- Power flux = P/a = σT^4 - σ = Stefan Boltzmann constant - T = Temperature - P = Power - a = Area

Question 26

Stefan Boltzmann constant

Answer 26

5.67 x 10-8 (W/m2K4)

Question 27

EMR emissions

Answer 27

- Everything with a temperature emits EMR - Wavelength is function of temperature of emitting body - Solar EMR (solar radiation) is emitted across spectra (visible wavelengths, infrared, UV) - Terrestrial EMR is predominantly infrared

Question 28

Greenhouse effect

Answer 28

- Atmosphere acts as a blanket on Earth - By trapping radiation ‘inside’ (atmosphere, or garden greenhouse), warms up the environment. - Atmosphere is dominated by Nitrogen

Question 29

Greenhouse gasses

Answer 29

- Atmosphere is transparent to visible EMR - GreenHouse Gases (GHGs) absorb UV and Infrared EMR warming the atmosphere

Question 30

Clouds and EMR

Answer 30

Clouds block all EMR because they are made of liquid or solid water

Question 31

Main two greenhouse gasses

Answer 31

- Carbon dioxide and methane - Part of complex system

Question 32

Carbon reservoirs

Answer 32

- Atmosphere - Oceans - Living things - Once living things (fossils, methane hydrates, permafrost) - Rocks

Question 33

Rock weathering

Answer 33

Carbonic acid dissolves rocks

Question 34

Carbonate precipitation

Answer 34

Coral and crustacean growth