Chapter 19: Global Change in the Earth System Flashcards

1
Q

Why does the Earth change constantly?

A
  • A plastic asthenosphere permits tectonic plate motion.
  • A star is close enough to warm Earth and its atmosphere.
  • Liquid water is possible; thus, weathering and erosion.
  • Biotic evolution continually modifies the biosphere.
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2
Q

Life on Earth is due to interactions among the:

A
  • Lithosphere
  • Atmosphere
  • Hydrosphere
  • Biosphere
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3
Q

What is the “Earth System” composed of?

A

The “Earth System” is composed of these physical components interacting with the biosphere.

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4
Q

What are the types of changes?

A
  • Gradual change
  • Catastrophic change
  • Unidirectional change
  • Cyclic change
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5
Q

Unidirectional changes include:

A
  • Evolution of the solid Earth
  • Formation of the Moon
  • Evolution of the atmosphere and oceans
  • Evolution of Life
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6
Q

Explain how evolution of the solid Earth is a unidirectional change

A
  • Planetesimal accretion

- Melting and differentiation

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7
Q

Explain how formation of the Moon is a unidirectional change

A
  • Mars-sized protoplanet collides
  • Mantle blasted into space
  • Debris coalesced to form the Moon
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8
Q

Explain how evolution of the atmosphere and oceans is a unidirectional change

A
  • Volcanic gases created an early atmosphere.
  • CO2, H2O, N2
  • Liquid water condensed to form the oceans.
  • Photosynthetic organisms appeared.
  • O2 becomes a significant component of the atmosphere.
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9
Q

Explain how evolution of life is a unidirectional change

A
  • Life appeared on Earth about 3.8 Ga.
  • Multicellular organisms appeared in Late Proterozoic and early Phanerozoic.
  • Life inhabits all regions, within a few km of Earth’s surface.
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10
Q

Give examples to physical cycles

A
  • the supercontinent cycle

- the rock cycle

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11
Q

Explain the supercontinent cycle

A
  • Plate tectonics drives continental movement.
  • Ocean basins open and close.
  • Continental landmasses collide and rift apart.
  • Supercontinents (like Pangaea) have formed several times.
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12
Q

Explain the rock cycle

A

there are three types of rock:

  • Igneous—cooled from a melt.
  • Sedimentary—made of weathered and eroded materials
  • Metamorphic—rocks altered by heat and pressure

One rock type may transform into any other type.
The atoms in rocks are constantly being rearranged.

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13
Q

How do climate studies reveal our past and suggest our future?

A
  • Distinguish kinds of climate changes
  • Establish rates at which these changes occur
  • Determine the effects on Earth and its inhabitants
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14
Q

What are the methods of climate studies?

A
  • Paleoclimates—investigations of past climatic variation

- Computer simulations—modeling past and future changes

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15
Q

What is the greenhouse effect?

A
  • H2O, CO2, and CH4 in Earth’s atmosphere absorb thermal energy and reradiate it, warming the lower atmosphere.
  • This is called the greenhouse effect.
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16
Q

What are paleoclimates? Give an example

A

Past climates are interpreted by datable Earth materials that are climate-sensitive.

E.g. Stratigraphic records—sequences of rock strata

  • Depositional environments are often climate-sensitive.
  • Glacial tills—cold and continental
  • Coral reef— tropical marine
17
Q

How do oxygen isotopes determine paleoclimates?

A
  • Oxygen isotopes—two isotopes: 16O and 18O
  • 16O water evaporates faster than 18O water.
  • 18O/16O in ice cores reveal the temperature in which snow formed.
  • Oxygen isotope ratios are preserved in carbonate shells of organisms.
  • The oxygen in CaCO3 shells mirrors oceanic 18O/16O.
  • Sea-floor sediments preserve ocean chemistry and temperature changes.
18
Q

here have been at least _____ major icehouse periods in Earth’s geologic history.

19
Q

What causes long-term climate changes?

A
  • Complex interactions across the Earth System
  • Plate tectonics modifies the position of continents.
  • Uplift of land surfaces influences atmospheric circulation.
  • Formation of coal and oil removes carbon from atmosphere.
  • Evolution of life affected atmospheric composition.
20
Q

Short-term climate changes regulated by several factors:

A
  • Fluctuations in solar radiation and cosmic rays
  • Changes in Earth’s orbit and tilt
  • Changes in volcanic emissions
  • Changes in ocean currents
  • Changes in surface albedo
  • Abrupt changes in concentrations of greenhouse gases
21
Q

How did humans impacted the Earth’s System?

A
  • Prehistoric humans were few, having a small impact. Today, humans are a huge force of planetary change.
    -Exponential population growth aided by advancements in:
    Industry, agriculture, technology, and medicine; fueled by a suitable supply of natural resources
  • Human demands often rival or exceed some natural processes.
    -Landscape modifications
  • Ecosystem modification—balances are destabilized. Destroys habitats
  • Pollution—materials that harm life forms and resources
  • Modern human society generates contaminants.
  • ## Recent global warming—human greenhouse gas additions alter climate.
22
Q

How do landscape modifications affect the Earth’s System?

A

Human-induced erosion may exceed natural processes.

23
Q

How do ecosystem modifications affect the Earth’s System?

A
  • Human-caused changes occur faster than indigenous organisms can adapt.
  • Rainforest decline is largely the result of human activity.
  • Deforestation
  • Overgrazing
  • Agriculture
  • Urbanization
24
Q

How does pollution affects the Earth’s System?

A

materials that harm life forms and resources

25
How do contaminants affect the Earth's System?
- Contaminating materials are numerous and diverse. | - They are produced so fast that the natural environmental systems can’t absorb or modify/neutralize them.
26
Explain how human greenhouse gas additions alter climate
- O2 in the atmosphere has steadily climbed since the industrial revolution began. - Ice core data show atmospheric CO2 in 1750 was ~ 280 ppm. - In 1958, CO2 was ~315 ppm; in 2010, CO2 was ~390 ppm - Human additions of CO2 and CH4 exceed natural removals. - Fossil fuel combustion (CO2) - Rice-paddy decay (CH4) - Cow flatulence (CH4)
27
Thousands of observations worldwide have documented effects of recent global warming such as:
- Large ice shelves, like the Larsen B along the Antarctic Peninsula, are breaking up. - The summer melt line indicates that melting of the Greenland ice sheet is accelerating. - Valley glaciers worldwide are retreating. - Arctic Ocean sea-ice is reduced.
28
The predicted effects of global warming are:
- Stonger storms due to a more vigorous hydrologic cycle: - Higher sea-surface temperatures - Greater evaporation - Greater differential pressures - 2005 set a number of storm records - A rise in sea level - Warming will accelerate this trend by: - Thermal expansion of seawater - Melting ice
29
Many scientists think that global warming could lead to:
- Interruption of the oceanic heat conveyor system. - Polar ice meltwater is freshwater. - Would dilute surface ocean water near the poles. - This freshwater won’t sink and move southward. - Thermohaline circulation would stop preventing warm water from flowing northward.
30
What is going to happen to Earth's System in millions of years?
- Earth’s surface will be different. - Plate tectonics will reshuffle continents. - Erosion will reshape the landscape. - Seas will invade or expose land. - Homo sapiens may no longer be present. - A new species of hominids might have evolved by then.
31
What will happen to the Sun in 5 billion years?
In about 5 billion years, the Sun will run out of fuel and become a red giant. - Earth will dry out. - It will become vaporized.