Midterm Flashcards

1
Q

The main chemical component of the lower atmosphere by total volume is…?

A

nitrogen

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2
Q

what season is in Australia when the earth is positioned as it is shown in the diagram below… north pole to the right left side shaded, sun rays coming from the right

A

winter

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3
Q

positive earth climate system feedbacks always:

A

amplify changes initially caused by external forcing

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4
Q

Which of the following CANNOT be used as a source of geochemical climate data?
A) planktonic forms (such as foraminifera or Radiolara)
B) cave deposits
C) seasonal snow cover
D) glacial ice
E) trees

A

seasonal snow cover

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5
Q

The influence on the climate of carbon dioxide is mainly due to its ability to absorb..

A

infrared radiation

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6
Q

When considered within the time scale of the last 300 million years, what is the present-day state of earth’s climate?

A

Earth is much colder today than it was 100 million years ago

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7
Q

Earth’s average temperature today is:

A

15.5°C

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8
Q
If the sun were to suddenly brighten and send more energy what climate systems components would respond most slowly?
A) the atmosphere
B) ice sheets
C) sea ice
D) vegetation
E) surface ocean
A

ice sheets

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9
Q

The part of the atmosphere that creates weather and supports life

A

is troposhere

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10
Q

Which two types of biotic data are most important to climate reconstructions?

A

microfossils of plankton and pollen

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11
Q

Infrared energy is mainly absorbed in the greenhouse effect by which two gases?

A

water vapor and carbon dioxide

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12
Q

what causes the observed annual rise and fall of carbon dioxide in the atmosphere?

A

seasonal changes in the rate of photosynthesis in the Northern Hemisphere

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13
Q

What place on earth experiences the largest annual temperature range?

A

Asia

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14
Q

What is the driving force for the Hadley cell atmospheric circulation pattern?

A

equatorial heating

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15
Q
Which of the following has the highest average albedo?
A) desert sand
B) forest
C) ocean water
D) ocean water covered w/ sea ice
E) grassland
A

ocean water covered w/ sea ice

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16
Q

What effect does sea ice have on atmospheric temperature?

A

Sea ice prevents the release of heat from the ocean beneath, allowing air temperatures to get much colder in the winter.

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17
Q

What of the following correctly describes the Intertropical Convergence Zone(ITCZ)?
A) In the ITCZ, converging air rises and forms clouds
B) The trade winds flow out of the ITCZ towards the tropics
C) The ITCZ is located in the tropical area around 30°N and S
D) The ITCZ is an area of permanently high pressure

A

In the ITCZ, converging air rises and forms clouds

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18
Q

Oxygen (O2) is being added to the atmosphere by..

A

vegetation

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19
Q

What effect do mountain ranges have on the distribution of precipitation?

A

Precipitation is enhanced on the windward side and reduced on the leeward side.

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20
Q

Which of the following statements about monsoonal circulation is CORRECT?
A) High pressure over continental surfaces leads to heavy precipitation on land
B) Monsoons are caused by a malfunction of the Hadley cell circulation
C) Summer monsoons tend to produce precipitation over continental surfaces
D) The strongest monsoon circulations occur when there are little seasonal differences in the surface heating between the land and ocean

A

Summer monsoons tend to produce precipitation over continental surfaces.

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21
Q

What is one direct result of the circulation of molten iron in Earth’s core?

A

Earth’s magnetic field

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22
Q

what allows lithospheric slabs to move?

A

a soft, easily deformed layer of the mantle just below the lithosphere

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23
Q

Which one of the following regions is the site of a convergent plate boundary?
A) San Andreas fault, Western North America
B) the Himalayas and the Tibetan Plateau
C) the east coast of North America (think of NY and NJ)
D) the Atlantic Mid-Ocean Ridge

A

the Himalayas and the Tibetan Plateau

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24
Q

The greenhouse effect:
A) describes the process by which incoming solar radiation is trapped in the troposphere
B) keeps Earth’s average temperature such that liquid water can exist at Earth’s surface
C) is a synonym for global warming
D) all of the above

A

keeps Earth’s average temperature such that liquid water can exist at Earth’s surface

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25
Q

With a weak Sun, why wasn’t earth frozen for the first two-thirds of its history?

A

The atmospheric carbon reservoir was much larger in earth’s early history than it is today.

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26
Q

Can volcanic input of C02 into the atmosphere be considered a plausible candidate for the Earth’s climatic thermostat?

A

No, b/c the rate of volcanic activity is not influenced by atmospheric conditions

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27
Q

Chemical weathering by hydrolysis of silicate rocks on the continents:

A

transfers carbon-containing ions to the ocean where they are later stored in the shells of marine plankton

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28
Q

Where did the extra carbon dioxide (CO2) from Earth’s early atmosphere ultimately go to?

A

sediments and rocks in Earth’s crust

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29
Q

What is the relationship between temperature and chemical weathering?

A

When climate initially warms, chemical weathering decreases atmospheric CO2

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30
Q

Tectonic (lithospheric) plates:

A

are rigid slabs of the crust plus the uppermost mantle

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31
Q

Time scales of climate change

A

the last 300 million years, the last 3 million years, the last 50,000 years, and the last 1,000 years

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32
Q

Components of climate system

A
  • Air
  • water
  • ice
  • land
  • vegetation
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33
Q

Climate forcing

A
factors that drive climate changes (causes)
• Tectonic processes
• Changes in Earth’s orbit
• Changes in the Sun’s strength
• Anthropogenic forcing
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34
Q

Climate responses

A

the resulting changes (effects)
• The response time is the rate at which water (or air temperature or any other climate component) warms or cools toward an equilibrium temperature
• Each part of the climate system has its characteristic response time (from hours to thousands of years)

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35
Q

Feedbacks of the climate system

A

processes that alter climate changes either by amplifying or by suppressing them.

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36
Q

Positive feedbacks

A

growth of glaciers during climate cooling or melting of glaciers during climate warming

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37
Q

Negative feedbacks

A

increased evaporation and cloud cover during climate warming

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38
Q

Difference between weather and climate

A

Weather - Short-run atmospheric conditions

Climate – pattern of day-to-day weather conditions over a long period

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39
Q

What are sediment archives?

A

layered rocks accumulating on the ocean floor, along the coastline, and in continental lakes

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40
Q

What are examples of other climate archives?

A

glacial ice, corals, tree rings, lake pollen, cave stalactites

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41
Q

Pollen - a proxy indicator of climate on land

A
  • Pollen is used for reconstructing younger climate intervals
  • 60 microns – the diameter of a sand grain
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42
Q

Plankton: a proxy indicator of climate in

the ocean

A

Shelled remains of plankton:

  • foraminifera and coccoliths contain CaCO3
  • diatoms and radiolaria contain SiO2
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43
Q

How can radioactive decay of unstable isotopes be used to determine the age of some rocks, corals, or organic materials?

A

Every element has a certain half-life (time it takes for the parent isotope to develop into the daughter isotope), so depending on which stage the element is or how many half-lives it has undergone is an indicator of how old some rocks or geologic material is.

44
Q

Can liquid water exist on Mars or Venus?

A

No, because Venus is so hot that water will instantly vaporize into gas.
Mars does not have an atmosphere to trap water on its surface, therefore no liquid water can exist (there used to be an atmosphere and magnetic field and there is evidence of water once existing on Mars, but not today).

45
Q

What would be an appropriate climate archive for reconstructing climate 50 million years ago?

A

Looking at sedimentary rocks is a good climate archive because they leave traces of evidence of glacial ice or calcium carbonate shells of plankton, which reveal climate conditions at the time they lived.

46
Q

Why is it incorrect to talk about climate change since last year?

A

Because climate is a result of looking at the long-term and scale matters when addressing climate concerns

47
Q

Seasons:

A

the combined effect of rotation, revolution, tilt, axial parallelism and spherical shape

48
Q

Effects of Earth’s movements:

A
  • day and night change – the result of Earth’s rotation on its axis
  • seasonal change and day length change – the result of Earth’s revolution around the Sun with the tilted axis
49
Q

WHAT IS THE CHEMICAL COMPOSITION OF THE TROPOSPHERE?

A

GREENHOUSE GASES: WATER VAPOR (~1-3%), CARBON DIOXIDE CO2 (0.04%), METHANE CH4 (0.00018%)

50
Q

Atmosphere: Vertical Structure

A

• Ionosphere – outer atmosphere
- 80 km (50 mi) outwards to 700 km (440 mi)
• Inner Atmosphere (troposphere, stratosphere, mesosphere)
- from Earth’s surface to 80 km (50 mi)
- Gases evenly blended
• Most important weather and climate changes happen in troposphere
- 8-18 km height

51
Q

Warm air rises around the equator, creating a ___ pressure area known as the __________. The air at higher altitudes moves poleward forming a large-scale circulation pattern known as the _____

A

low
ITCZ
Hadley Cell

52
Q

Much of the air sinks back to Earth at about 30°N and S, producing a ____ pressure area known as the ___________.

A

high

Subtropical Highs

53
Q

Pressure gradient between the tropics and the ITCZ causes surface air to flow from the ___ toward the ___

A

tropics to the equator

54
Q

the flow of air between the tropics is known as the

A

trade winds

55
Q

As air flows along the surface toward the ITCZ, it is deflected due to the _________. As a result, the trade winds blow from __ to __ in the Northern Hemisphere, and from ___ to __ in the Southern Hemisphere.

A

Coriolis effect
NE to SW
SE to NW

56
Q

Air moves from tropics toward poles as well as toward equator. This poleward movement, combined w/ same kind of deflection, gives rise to mid-latitude winds known as ______. The general direction of these surface winds is from ___ to ___.

A

westerlies

west to east

57
Q

Cold air sinks over the poles and produces areas of ____ pressure

A

high

58
Q

Winds blow out of high pressure zone and produce

A

easterlies winds.

59
Q

Monsoons

A

seasonal reversal of the winds, onshore flow in summer from sea to land, and offshore flow in winter from land to sea

60
Q

The hydrologic cycle

A
  • Continuing recycling of water among three reservoirs
  • Oceans contain 97% of Earth’s water
  • Glaciers contain 2% of water
  • Atmospheric moisture, surface and ground water, biological and soil water ~1%
61
Q

ALL CLOUDS FORM BY THE PROCESS OF ADIABATIC COOLING OF RISING AIR

A
  • An ascending parcel of air cools adiabatically by expansion
  • Air must be saturated for condensation (cloud formation) to start
  • Lapse rate - the rate at which Earth’s atmosphere cools
  • Average lapse rate 6.5°C/km
62
Q

What is Chemical weathering?

A

The chemical alteration of rock’s minerals (agents: H2O, CO2, O2), prevails in warm humid areas, two major types is hydrolysis: formation of clays and dissolution of limestone, and carbonation which is water that dissolves CO2 from the air, the solution acts as a weak acid.

63
Q

VOLCANIC CO2 INPUT

A
  • The largest reservoir of carbon on Earth is in rocks (on Venus – in atmosphere)
  • Major input of CO2 to atmosphere is from volcanic activity and hot springs
  • Natural rates of CO2 input and removal are ~ balanced
  • Without this input CO2 will be removed from atmosphere in ~4,000 years
  • Volcanic processes are not affected by the atmosphere
64
Q

“Thermostat” concept:

A

warming the climate when the Sun was weak and cooling it later as the Sun strengthened

65
Q

What controls Earth’s “thermostat”?

A

Balance between CO2 input through volcanism and removal through chemical weathering

66
Q

Rates of chemical weathering regulated by three environmental factors

A
  • Temperature
  • Precipitation
  • Vegetation
67
Q

The faint young Sun paradox

A

talks about how the early Sun shone 25% to 30% weaker than today along with climate models showing that Earth should have been frozen even with greenhouse gases present.

68
Q

The “snowball earth” hypothesis

A

hypothesis that Earth was frozen even in tropics sometime in interval between 850 and 550 Myr ago.

69
Q

Types of plate boundaries

A

convergent
divergent
transform

70
Q

convergent boundaries

A

between two lithospheric plates that move toward each other and cause collision of continents or subduction of one plate beneath the other
a) Oceanic-Continental:
mountain ranges on the continental edges, deep oceanic trenches, granite volcanism
Example: the Andes
b) Oceanic-Oceanic:
deep ocean trenches, volcanoes on the ocean floor , volcanic island arcs
Examples: the Aleutian Islands, the Mariana Islands, the Japan Islands.
c) Continental-Continental:
no subduction or volcanism, mountain ranges, frequent earthquakes
Examples: the Alps, the Himalayas, the Appalachians

71
Q

divergent boundaries

A

between two lithospheric plates that are moving apart, usually at crest of ocean ridge

72
Q

transform boundaries

A

between lithospheric plates at which plates slide past each other
• No volcanism
• High earthquake activity
• Example: the San Andreas Fault in California

73
Q

The Polar Position hypothesis

A

that ice sheets exist during intervals in Earth’s history when landmasses are moved into Polar Regions by plate tectonic processes

74
Q

The Spreading Rate hypothesis

A

that tectonic-scale climate changes are driven by variations in global average rate of seafloor spreading, which alter amount of CO2 introduced into atmosphere.

75
Q

The Uplift Weathering hypothesis

A

that tectonic-scale climate changes are caused when uplift of plateaus and mountains alters amount of CO2 removed from atmosphere by chemical weathering of fragmented rock

76
Q

Modeling Pangaea’s climate 200 MYA:

A
  • The Sun 1% weaker than today
    However:
  • No evidence of ice sheets
  • Palm-like vegetation at latitudes ~40°N and S
    Based on fossil evidence, the CO2 level was much higher than today
77
Q

The “greenhouse” world 100 million years ago

A
  • Large areas of the continents were flooded by shallow sea

- Much higher CO2 (at least 4X) concentrations

78
Q

Why was sea level much higher 100 MYA?

A
  1. Tectonically driven changes in the volume of ocean basin
    •Today most crests of the ridges lie 2,500 m below sea surface
    •Fast spreading creates wider ridge profiles that reduce volume of ocean basins
    •Most plate tectonic movements create net zero effect on either oceans or continents
    •Only in continental collisions the crust thickens b/c of stacking slivers of continental crust
    •Oceanic basins increase in area and sea level drops
    •most dramatic continental collision happened later, 55 MYA (The Eurasian Plate and the Indian subcontinent)
  2. Climatically driven changes in volume of ocean water
    •Sea level is estimated to be ~ 125 m (375 ft) higher than today
    •Absence of glaciers 100 MYA made sea level 65 meters higher than today
79
Q

What was the main environmental impact of the asteroid impact 65 million years ago?

A

Coincided with a global-scale extinction of 70% of the species

80
Q

What were the instant environmental impacts of the asteroid impact 65 million years ago?

A

There were global wildfires, vaporization of water and rocks-warming

81
Q

What were the Medium-term environmental impacts of the asteroid impact 65 million years ago?

A

It is due to dust and soot blocked insolation (months/years) - cooling

82
Q

What were the Longer-term environmental impact of the asteroid impact 65 million years ago?

A

It would be due to an atmospheric CO2 increase (decades/centuries)- warming

83
Q

The Thermal Maximum episode 56 MYA

A
  • Unusually fast warming (over 20,000 years) by 5°C
  • Spread of warm-adapted species into high latitudes
  • Major carbon release measured through carbon isotope analysis
  • Possible explanation: massive release of methane clathrate (or methane hydrate) CH4
  • Can be released if subsurface ocean warms significantly
  • The initial trigger is uncertain
84
Q

GLOBAL COOLING 50 MYA: FROM GREENHOUSE TO ICEHOUSE EARTH

A
  • When climate cools, two kinds of glaciers emerge
  • No evidence of ice in Antarctica until 35 MYA
  • Greenland ice sheets first developed between 7 and 3 MYA
85
Q

What was The Gateway Hypothesis?

A

It was due to the opening of the Drake’s Passage ocean gap between Antarctica and South America, strong Antarctic circumpolar current instead of poleward movement of warm tropical waters, and time of this event estimated between 37 and 17 MYA

86
Q

What were other factors of The Gateway Hypothesis?

A

Newly formed Gulf Stream carried salty warm water to the NW, the formation of sea ice in the Northern Atlantic is suppressed, and there was more moisture from the ocean triggered growth of ice sheets on the northern continents

87
Q

What are examples of the Uplift Weathering Hypothesis?

A

India-Asia collision and the uplift of the Tibetan Plateau and Initial collision 55 MYA.

88
Q

What are examples of future climate change at tectonic million-year scale?

A

Long-term chemical weathering thermostat can be still working, a global temperature decrease by 3-4°C could be enough to reduce weathering rates by 50% over the remaining 99% of not uplifted land surface; hence, negative feedback from chemical weathering, but if tectonic uplift results in global cooling a positive feedback from increased weathering is possible.

89
Q

What are two main possible reasons of future climate change at a tectonic million-year scale?

A

large continental ice sheets and increased rock fragmentation due to growth of mountain glaciers

90
Q

What is the most likely reason for global cooling during the last 50 MY?

A

It would be due to decreased atmospheric CO2 driven by a combination of decreased input from sea-floor spreading and increased removal due to chemical weathering

91
Q

The most likely reason for global cooling during the last 50 MY is

A

decreased atmospheric CO2 driven by a combination of decreased input from seafloor spreading and increased removal due to chemical weathering

92
Q

When climate warms up, increased evaporation results in increased cloud formation and clouds lower the amount of solar radiation that can reach the surface. What kind of climate feedback is present here?

A

This is a neg. feedback loop because the initial warming instigated cloud formation which blocked or reflected more incoming sunlight, therefore avoiding more heating and ultimately cooling the planet

93
Q

WHY IS SUMMER ALWAYS WARMER THAN WINTER AT THE SAME LATITUDE?

A

Larger solar angle of incidence, longer hours of daylight

94
Q

WHAT IS THE DIFFERENCE BETWEEN SUMMER AND WINTER MONSOON?

A

During the summer monsoon, the land area has LOW pressure and the ocean has HIGH pressure. We know that air travels from H → L, which explains why the ocean air flows toward the land during this time. Since the land is warm, the water will rise and form precipitation. The opposite of this process will occur during the winter monsoon because the pressures switch (now land has HIGH pressure and ocean and LOW, meaning rain will fall in the ocean but this does not affect people → this is why most tourists will want to visit Thailand or Indonesia during the winter months).

95
Q

WHY ARE THE HOTTEST AND DRIEST REGIONS ON EARTH (DESERTS) LOCATED IN THE TROPICS?

A

This has to do with the uneven distribution of temperature which influences pressure and, consequently, wind patterns on Earth. Air starts rising around the equator due to low thermal pressure and net surplus of solar radiation and the Hadley Cell effect drops this air around subtropical zones (30S and 30N). This air then sinks in the high pressure areas and by the time it reaches this part the air has become dry (no longer humid and moist).

96
Q

ALBEDO OF WHICH OF THE FOLLOWING SURFACES IS HIGHER:

A FORESTED AREA OR A DESERT? AN OCEAN SURFACE OR A SKATING RINK?

A

Albedo is higher in a desert (sand reflects because lighter, forested area is dark and absorbs heat instead), and albedo is also higher at a skating rink (again, the paleness of the rink reflects more light than a dark ocean surface).

97
Q

WHAT IS THE GLOBAL PATTERN OF DISTRIBUTION OF COLD AND WARM SURFACE CURRENTS?

A

In the Northern Hemisphere, mid-latitude southwesterly winds and tropical northeasterly trade winds drive warm water toward the centers of subtropical gyres, forming a thick lens of warm water that circulates in a clockwise gyre.

98
Q

What kind of feedback is provided by the decreased sea ice cover during a climate warming episode?

A

A decrease in Sea ice means the Earth’s albedo becomes lower, therefore increasing the initial warming. This is a positive feedback loop.

99
Q

What is the largest source of atmospheric carbon dioxide on Earth?

A

Volcanic eruptions.

100
Q

What is the largest pool of carbon on Earth?

A

Sedimentary rocks which store carbon.

101
Q

What is the relationship between vegetation cover and albedo? What kind of feedback does change in vegetation cover provide when climate is cooling?

A

If there is a lot of vegetation, albedo is low and Earth warms. Think of tropical rainforests. However, when the climate is cooling, vegetation may be covered in permafrost or snow and increase reflectivity, initiating a positive feedback loop.

102
Q

What is the reason for small annual oscillations of CO2 in the atmosphere?

A

From a purely natural world perspective, photosynthesis levels fluctuate based on how much sunlight plants receive. CO2 will be more prevalent in the air during fall-winter months because plants in the Northern hemisphere will be experiencing less sunlight and therefore will be uptaking less CO2 for photosynthesis purposes. Also, less rain during summer for N. hemisphere, and less precipitation means less chemical weathering (which also removes CO2 from atmosphere).

103
Q

True or False?

The reason Venus is so much hotter than Earth is that Venus is much closer to the Sun.

A

False

104
Q

Why are there no volcanoes along a transform plate boundary?

A

Transform plate boundaries simply slide against each other rather than colliding with each other (the latter results mainly in earthquakes, while the former creates uplift of potential volcanic mountain ranges and earthquakes).

105
Q

Do sea level changes explain past glaciations? In other words, what is the cause-effect relationship between sea level change and climate change?

A

yes, sea level changes reflect past glaciations and provide insight to climate change. Evidence has to do with the oxygen isotopes (O16, lighter and found in surface level water vs O18, heavier and more likely to be trapped in ice sheets).

106
Q

What kinds of changes in vegetation in the Northern Hemisphere show that Earth has cooled over the last 50 MY?

A

“Spread of cool boreal spruce forest in Arctic”
Broad leafed evergreen + deciduous forest in Arctic
Palm like trees + crocodile ancestors
Fossil remains of vegetation (ex. Beech tree aka Nothofagus)
“Conifers forests of spruce and larch (20 million yrs) indicates cooling
Tundra (grasslike vegetation), living on “thawed layers above permafrost” (severely frozen ground during winter)