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ATMS 211 > Final Exam > Flashcards

Final Exam Flashcards

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1
Q

Most of the time, the climate was _____ (warmer/cooler) than today

A

warmer

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2
Q

during 6 periods of time, extensive ______ occured

A

glaciations

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3
Q

What period did Snowball Earth events occur?

A

Neoproterozoic

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4
Q

What are the 5 points of evidence of glaciation?

A
  1. Glacial Striations from abrasion
  2. Dropstones
  3. Banded Iron Formations
  4. Cap carbonates
  5. Paleolatitudes + magnetism
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5
Q

Glacial striations from abrasion

A

glaciers can freeze to the rock they are moving over and “pluck” rocks, entraining them into the ice. As the glacier moves, the rocks and sediment near the base of the ice scrape against the bedrock and abrade it.

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6
Q

Dropstones

A

when ice reaches the ocean, it will calve off, forming icebergs. when those icebergs melt, they will drop any rocks that were entrained in the ice.
*stones dropped from above (by glacial ice) into soft sediment layers at the bottom of an ocean/lake.

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7
Q

Banded iron formations

A

during a snowball earth, little oxygen exchanged between atmos/ocean. w/out oxygen reaching the deep ocean, iron just remained dissolved in water. but when ice melted, oxygen could mix into the ocean, triggering iron oxidation and sink to the bottom of the seafloor

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8
Q

Cap carbonates

A

rocks formed very quickly after a snowball earth episode. as the ice melts, lots of fresh water is dumped into the oceans, the less acidic envir made it easier for limestone to be depositied

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9
Q

Paleolatitudes and magnetism

A

continents configured really differently, magnetic fields of magnesium of rocks.

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10
Q

What kind of radiative forcing could have initiated a snowball earth episode? Do we need a positive or negative radiative forcing? Shortwave or longwave?

A

Negative shortwave radiative forcing and longwave radiative forcing

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11
Q

what caused the longwave negative radiative forcing that reduced GHG and caused snowball earth?

A

CO2 is drawn out of the atmos through weathering

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12
Q

weathering

A

When the land is clustered into a supercontinent, it is hard for rainclouds to
make their way into the interior. As the supercontinent broke up, rain could fall over more land surface → more
weathering

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13
Q

What caused the shortwave radiative forcing that resulted in snowball earth?

A

widespread volcanic eruptions

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14
Q

runaway ice-albedo feedback

A
  1. a cooling is initiated
  2. polar ice sheets gradually expand
  3. more sunlight reflected away
  4. earth cools some more
  5. repeat until most incoming sunlight is reflected away, instead of being absorbed
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15
Q

if earth ever became ice covered, how could the ice ever melt?

A
  1. extremely high ghg concentrations from volcanic eruptions
  2. no chemical weathering (due to no rain/precipitation b/c no evaporation)
  3. CO2 accumulation –> high GH effect
  4. GH effect so strong –> melting
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16
Q

during snowball earth _______ injected co2 into the atmosphere

A

volcanoes

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17
Q

what was the temperature of the earth after melting snowball earth?

A

very hot

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18
Q

what brought down the post snowball “hothouse” climate

A

massive amounts of weathering bringing down co2 and temps

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19
Q

How did life survive during snowball earth?

A
  1. cracks in the ice
  2. refuges of open water
  3. hypothermal vents
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20
Q

during the _______ era the Earth was mostly
warm, but then it dipped into a significant glacial period
* The glacial cooling was probably due to a decrease in CO2
levels

A

Palaeozoic

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21
Q

During the mesozoic era, sea-levels were _________ (higher/lower) than the present

A

higher

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22
Q

why were sea levels so high in the mesozoic era?

A

no ice sheets at all
thermal expansion of sea water
ocean was less deep

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23
Q

Paleocene-Eucene Thermal Maximum

A

the quick jump in temperature 55 million years ago – 5c in the tropics and 9c at the poles
high co2 levels in the atmosphere

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24
Q

proposed mechanisms of the PETM warming of the ocean

A

volcanism
comet impact
burning of peat on land
tectonic instabilities

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25
What led us from the warm Mesozoic to the Pleistocene?
- movement of the continents (more weathering) - slowdown in continental drift
26
would an increased weathering rate serve to WARM or COOL the planet
cool
27
the ice ages
large ice sheets covered Northwestern Europe and North north america
28
What changes happen during a glacial period?
ice cover on land extends equatorward - glacials: the northern hemisphere is extensively glaciated - interglacials: shorter intervals where extensive glaciation is limited to
29
glacials
the Northern Hemisphere is extensively glaciated
30
interglacials
shorter intervals where extensive glaciation is limited
31
during an ice age, we expect the sea-level would be (higher/lower) and (more/less) land surface to be exposed
lower;more
32
LGM
last glacial maximum
33
The continents were (clustered/current configuration) during the ice ages
current configurations
34
where were the glaciations during the ice ages?
present day Canada and northern Europe
35
Evidence of Ice ages
- Glacial erratics and striations - Ice cores - Sediment cores
36
What are two sources of past temperature data for ice ages?
Ice cores (1 million years) and sediment cores (more than 1 million)
37
If your sample has proportionately _______ 18O than the standard then this number will be more than 1, and so the temperature will be larger
more
38
If your sample has proportionately _______ 18O than the standard then this number will be less than 1, and so the temperature will be smaller
less
39
the _____ the water, the greater the tendency for calcium carbonate shells to incorporate 18O
colder
40
______ (lighter/heavier) isotopes (16O) evaporate more readily
lighter
41
______ (lighter/heavier) isotopes (18O) rain out more readily
heavier
42
During the glacial period... the water in the ocean has a relatively high amount of______ (heavy/low) oxygen _____ (16O/18O)
heavy; 18O
43
During the glacial period... the snow that is deposited in the ice sheets has a relatively high amount of______ (heavy/low) oxygen _____ (16O/18O
low; 16O
44
During interglacial warm periods....the water in the ocean has a relatively low amount of______ (heavy/low) oxygen _____ (16O/18O
heavy;18O
45
During interglacial warm periods...the snowfall deposited in the ice sheets has a relatively low amount of ______ (heavy/low) oxygen _____ (16O/18O)
low; 16O
46
What can we find out using ISOTOPIC EVIDENCE
1. Isotopes in ocean sediments record glacial ice volume (how much meltwater came off the ice sheet) 2. Isotopes in ice cores indicate local temperature (how much heavy-isotope snow was able to be deposited on the ice sheet)
47
What kind of information can you get from an ice core?
- Bubbles: atmospheric composition at the time of deposition - thickness of layers: precipitation rates - Chemistry of ice: temperature
48
Carbon dioxide concentrations varied between about 180ppm (glacial/interglacial) and 280ppm (glacial/interglacial)
glacial; interglacial
49
Why has Earth's climate system been oscillating between glacial and interglacial states, with apparent periods of 100,000 and 40,000 years?
The way Earth orbits the sun (Milankovitch cycles)
50
Milankovitch Cycles: Eccentricity
the shape of Earth's orbit changes about 3* from more elliptical to more circular (0-O) (100,000 year cycle)
51
Milankovitch cycles: Obliguity
the tilt of earth's axis changes between 22.1 and 24.5 degrees (40,000 year cycle)
52
when the axis is strongly tilted, the seasons become ______ (exaggerated/dampened)
exaggerated
53
Milankovitch Cycles: precession
the change in orientation of the axis. which way is the earth pointing whwen it is at its closest approach to the fun or at its furthest from the sun? Strengthens or weakens obliquity/eccentricity (26,000 year cycle)
54
The northern hemisphere is in the WINTERTIME during ______ (aphelion/perihelion)
perihelion
55
what orbital configurations would optimize glaciations?
Low axial tilt (obliquity) High eccentricity (more elliptical) Aphelion during Northern Hemisphere summer (precision)
56
Theory suggests that it is when _______ (obliquity/eccentricity) and (eccentricity/precession) conditions align that deglaciation can be triggered
obliquity/precession
57
Out of the Milankovitch cycles, which of the three parameters is the weakest forcing?
eccentricity
58
Per capita emissions would DECREASE if the country's emissions _______ (increases; decrease) OR the country's population ________ (increase/decrease)
Decrease; increase
59
Countries that have ______ (more/less) wealth tend to emit more co2
more
60
Attribution study
a study that can tell you if and how much climate change altered the likelihood of event
61
The start of the fasting season for polar bears is getting _______ (earlier/later) in the year, and the end of the fasting season is getting _______ (earlier/later). Overall, it is getting (shorter/longer)
earlier;later;longer
62
Projected that with warming, the PNW will (eventually) experience _______ (increasing/decreasing) snowpack as precipitation shifts between snow and rain
decreasing
63
What are the three ways we can address climate change?
1. Adaptation 2. Mitigation 3. Geoengineering
64
Adaptation
(Prevent harm; deal with symptoms) Alter human structures and practices in order to reduce the harmful effects of climate change
65
Mitigation
(Prevent climate change; deal with cause) Reduce emissions of GHGs in order to reduce the amount of climate change that takes place
66
Geoengineering
(Actively manipulate the climate system) Continue to emit GHG but pull them from the atmosphere OR reflect away incoming sunlight
67
What are adaptation strategies based on?
- each locations unique impacts - how much money is available equity, justice, cultural, national security
68
Mitigation strategies
reducing energy intensity, carbon use, (alternative energy sources)
69
Biochar
Organic material which is heated in a low-oxygen environment, and charcoal is produced. The carbon that would have been released to the atmosphere during decomposition is instead locked in this charcoal That charcoal is buried in the soil and improves soil health
70
Enhanced ocean alkalinity
The ocean more readily takes up CO2 from the atmosphere if it is less acidic. One way to make it more basic is to add more alkaline material to the ocean: e.g. ground up limestone or olivine. The ocean will then take up more atmospheric CO2 and convert the carbon into more stable forms (either dissolved in the water or incorporated into shells/skeletons).
71
Ocean fertilization
To increase biological uptake in the ocean, one idea is to add iron (a limiting nutrient) to the ocean. Phytoplankton bloom, and therefore photosynthesize more CO2 In theory, the carbon incorporated into the phytoplankton could sink and move to the deep ocean. In reality, most of the carbon stays near the surface, where it is respired/decomposed and is reintroduced to the atmosphere.
72
Afforestation and reforestation
another approach is to plant trees/replace trees in deforested areas on a large scale. this process captures co2 through photosynthesis, and the carbon is stored as plant biomass
73
enhanced weathering
just like the typical process of chemical weathering, but giving nature plenty to weather, and making it easy; Crush rocks with a high content of silicate material (such as basalt or olvine) and spread them over land surfaces
74
direct air capture
large fans pull air in. the co2 is chemically bound to a filter as the air blows through. when the filter is saturated, it is heated, and the co2 is concentrated, and can be stored in a geologic reservoir
75
types of geoengineering (6)
1. BIOCHAR 2. ENHANCED OCEAN ALKALINITY 3. OCEAN FERTILIZATION 4. AFFORESTATION AND REFORESTATION 5. ENHANCED WEATHERING 6. DIRECT AIR CAPTURE
76
What is the goal of solar radiation management (SRM)?
reduce shortwave radiation absorbed by earth (a negative forcing) to cancel the positive radiative forcing due to increase CO2, slowing or stopping global warming - a balanced energy budge would be the goal
77
Cloud modification (geoengineering) STEPS
1. Shoot a very fine spay of sea water into the air: makes cloud droplets smaller and thus more reflective of sunlight 2. works best in pristine (ocean) areas. Need thousands of ships 3. Downside: clouds are the weakest link in understanding climate change
78
If we want to reflect away a lot of incoming sunlight, we want clouds with a high albedo and a low greenhouse effect. What clouds are these?
Lots of little droplets and low-altitude
79
Stratospheric sulfur injections STEPS
1. inject a sulfate aerosol precursor into the stratosphere that then forms sulfuric acid solutions and eventually small particles 2. there aerosols increase earth's albedo by reflecting solar radiation back to space 3. when injected really high up & the particles remain small, they take a long time to fall out 4. cheap compared to some estimates of mitigation costs.
80
will geoengineering happed?
short term: inexpensive potentially a good "band-aid"

ATMS 211 (3 decks)

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