M2L3 - Climate Cont. Flashcards
1
Q
Written or Oral histories
A
- Either direct or indirect
- Nautical journals recording weather conditions
- Timing of harvest dates
- Oral history of lived experiences
2
Q
Corals
A
- 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)
3
Q
Pollen
A
- 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
4
Q
Ice cores
A
- 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
5
Q
Tree ring analysis
A
- Dendrochronology
- Can provide climate and environmental parameters
- Width of ring represents growth
6
Q
Lake and ocean sediments
A
- 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
7
Q
Earth’s eccentricity
A
- 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
8
Q
Obliquity
A
- Measure of change in axis of rotation
- Larger the tilt, the more extreme the seasons are
- 41k year cycle
9
Q
Axial precession
A
- How close we are to the sun in summer
- 23k year cycle
10
Q
Earth’s climate record
A
- Lack of data from before 500 million years ago
- Temporal resolution of data gets worse as you go back in time
11
Q
Pleistocene climate
A
Rhythmic patterns
12
Q
Holocene climate
A
Stability
13
Q
Milankovitch cycles
A
- 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
14
Q
Cretaceous alberta
A
- 144 to 66 million years ago
- Death and decomposition of plant and marine life
- Bacteria broke down light oil resulting in Bitumen
15
Q
Where did meteor that killed dinosaurs land
A
Chicxulub crater, mexico
16
Q
How did meteor kill dinosaurs
A
- 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)
17
Q
Paleocene-Eocene thermal maximum (PETM)
A
- 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
18
Q
Ice ages
A
- 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
19
Q
Interglacial
A
Period between ice ages
20
Q
Current ice age period
A
Interglacial period within the Quaternary Ice age
21
Q
The last glaciation
A
- Ice sheets over 3km thick sculpted much of canada
- Sea level 120m lower (continental shelves exposed)
- Land bridge to Asia
22
Q
End of the last glaciation
A
- Ice sheets retreat producing lots of water
- Glacial lakes form then drain
- Water drains to the oceans
- Sea level rises to current levels
23
Q
Electromagnetic radiation types (from long to short wavelength)
A
- Radio
- Microwaves
- Infrared
- Visible light
- UV
- X-rays
- Gamma rays
24
Q
Incoming solar radiation
A
- 29% reflected
- 48% absorbed at the surface
- 23% absorbed by the atmosphere
25
Q
Planck’s law
A
- Power flux = P/a = σT^4
- σ = Stefan Boltzmann constant
- T = Temperature
- P = Power
- a = Area
26
Q
Stefan Boltzmann constant
A
5.67 x 10-8 (W/m2K4)
27
Q
EMR emissions
A
- 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
28
Q
Greenhouse effect
A
- Atmosphere acts as a blanket on Earth
- By trapping radiation ‘inside’ (atmosphere, or garden greenhouse), warms up the environment.
- Atmosphere is dominated by Nitrogen
29
Q
Greenhouse gasses
A
- Atmosphere is transparent to visible EMR
- GreenHouse Gases (GHGs) absorb UV and Infrared EMR warming the atmosphere
30
Q
Clouds and EMR
A
Clouds block all EMR because they are made of liquid or solid water
31
Q
Main two greenhouse gasses
A
- Carbon dioxide and methane
- Part of complex system
32
Q
Carbon reservoirs
A
- Atmosphere
- Oceans
- Living things
- Once living things (fossils, methane hydrates, permafrost)
- Rocks
33
Q
Rock weathering
A
Carbonic acid dissolves rocks
34
Q
Carbonate precipitation
A
Coral and crustacean growth
