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T/F? Nearly all biological and chemical systems on Earth are disconnected and are best
studied in mutual isolation.


The presence of liquid water on Earth's surface is ____________.

A. unremarkable; many other bodies in the solar system have liquid water

B. unique within the solar system, but is an inherent feature of Earth that would be
found regardless of the Earth-Sun distance

C. unique within the solar system; liquid water would not have developed had Earth
been much closer to or farther from the Sun

been much closer to or farther from the Sun

T/F? All changes within the Earth system are unidirectional and cannot be reversed.


T/F? Cyclical global change includes the formation of core, mantle, and crust from a
homogeneous mixture, a state to which one day Earth will return.


Which of the following types of global change is not part of a cycle of change, and
thus irreversible?

A. orogenic uplift

B. melting and crystallization of sedimentary rock to form igneous rock

C. evolution of life on Earth

D. flooding of the continents due to global warming

C. evolution of life on Earth

Uplifted areas are subjected to weathering and erosion at the surface; this provides an
example of ____________.

A. unidirectional change

B. cyclical change

C. neutral feedback

B. cyclical change

Which of the following processes releases carbon dioxide to the atmosphere?

A. photosynthesis

B. weathering of silicate rocks

C. volcanism

D. deep burial of peat to produce coal

C. volcanism

Which of the following processes removes carbon dioxide from the atmosphere?

A. exhalation by animals

B. burning of coal and other fossil fuels

C. volcanism

D. photosynthesis

D. photosynthesis

Which of the following processes may be responsible for short-term cooling, yet in the
long term favors warm, greenhouse climate?

A. atmospheric carbon dioxide

B. formation of extensive ice sheets

C. volcanism

D. formation of large continents located near the poles

C. volcanism

T/F? Pollen has changed over time through evolution, but the pollen of individual species
cannot be used to interpret ancient environments because most species inhabit all


An increase through time in the proportion of heavy oxygen (18O) in a sequence of
carbonate sediments implies ____________.

A. the sediments are young enough to have been exposed to radiation from
underground nuclear testing

B. the organisms that secreted the carbonate favored 18O over the far more abundant 16O

C. Earth was becoming warmer over time

D. Earth was becoming cooler over time

C. Earth was becoming warmer over time

With the increased amount of information that has been discovered in recent years,
scientists have become increasingly certain that ____________.

A. Earth's climate is not warming to any significant degree

B. Earth's climate is warming due to variation in solar output; human inputs of
atmospheric greenhouse gases have not had a significant influence

C. Earth's climate is warming, and human inputs of atmospheric greenhouse gases are
most likely responsible

most likely responsible

During most of the Mesozoic, Earth was ____________.

A. about as warm as today

B. covered in extensive continental glaciers

C. about as warm as the Holocene climatic optimum

D. significantly warmer than at any time within the last few million years


Currently, global warming appears to be most strongly affecting the climate and
wildlife of ____________ regions.

A. equatorial

B. temperate

C. polar

D. deep sea

C. polar

T/F? Due to global warming, the Earth is now warmer than it ever has been in geologic


T/F? The factors that affect Earth's long-term climate are different from those that affect
climate on shorter time scales.


A newspaper editorial columnist this week writes a scathing attack on the scientific
consensus concerning global warming. His position is that global warming is not occurring,
and his supporting evidence is the fact that Sheboygan, Wisconsin, had a record low
temperature (in 150 years of record keeping) on February 6 last winter. Which statement(s)
about the editorial is/are correct?

A. Assuming the columnist is correct in reporting the record low temperature, then
indeed he is correct in his assertion that global warming is not occurring.

B. The columnist is confusing weather (day to day and seasonal variation in
temperature, humidity, precipitation, and air pressure) with climate (variability in
these factors over time scales of decades or longer).

C. The columnist does not understand that scientists do not expect global warming to
produce a gradual uniform increase in temperature for every locality on every day
of the year. Geologically rapid warming is expected to increase air and sea
temperature averaged across the planet throughout the year (measured over time
spans of decades to centuries), but it will also bring shifts in weather patterns that
could locally cause extreme heat or cold, drought, or intense flooding.

D. Both B and C are correct.

D. Both B and C are correct.

Which of the following is an important long-term (acting over spans of tens of millions
of years) factor in global climate change.

A. decrease in albedo due to aerosols from volcanic eruptions

B. variation in Milankovitch orbital parameters

C. variation in the abundance of sunspots

D. atmospheric concentration of carbon dioxide

D. atmospheric concentration of carbon dioxide

A crater discovered in the Yucatan peninsula in Mexico appears to be the right age to
be a result of an impact which brought about the extinction of numerous species at the end
of the ____________ period.

A. Silurian

B. Jurassic

C. Cretaceous

D. Tertiary

C. Cretaceous

The hole in the ozone layer has been brought about by anthropogenic emissions of

A. carbon dioxide

B. methane

C. chlorofluorocarbons (CFCs)

D. polychlorinated biphenyls (PCBs)

C. chlorofluorocarbons (CFCs)

What processes control the rise and fall of sea level on Earth?

Global sea level is primarily controlled by the volume of glacial ice on continents,
which has a negative effect, and the volume of mid-ocean ridge volcanoes, which has a
positive effect. At times of rapidly moving plates (abundant mid-ocean-ridge volcanism), an
increase in excess carbon dioxide leads to a stronger greenhouse effect, warming the ocean
and melting glaciers (if any are present), which raises sea level by adding ocean water.
Rapid volcanism also produces thick mid-ocean-ridge volcanic chains, which displace water
onto the continents. Conversely, when sea-floor spreading rates are low, ridge volume is
small and the atmospheric level of carbon dioxide is also low. The resultant reduction in the
greenhouse effect favors the formation of continental glaciers, freezing out water that is now
unavailable to the ocean.

How does carbon cycle through the various Earth systems?

Carbon dioxide in the atmosphere dissolves in the ocean to form carbonate (and
bicarbonate) ions. These ions are removed by a variety of organisms to produce calcite and
aragonite skeletons, which collect as fragments and grains at the bottom after the organisms
die, eventually forming limestone. Carbon dioxide can also be removed, either directly from
the atmosphere or from solution in the ocean, through biogenic photosynthesis, to produce
organic carbon. Organic carbon may become incorporated into the rock record in shale, oil,
and coal, but some may be released to the environment through animal respiration and
flatulence. Weathering of silicate rocks removes atmospheric carbon dioxide, producing bicarbonate ions. Burning fossil fuels releases atmospheric carbon dioxide, as do volcanic

How do paleoclimatologists study ancient climate change?

The record of sedimentary rocks can be used to decipher ancient climate change,
because certain rocks are characteristic products of specific environments; further, fossils
provide environmental clues because many organisms have narrow environmental
tolerances. Oxygen isotope ratios in ice and carbonate sediments provide a proxy for
average temperatures. Ancient air bubbles may reveal atmospheric carbon dioxide levels
(and thus the effectiveness of Earth's greenhouse). Variations in growth rings and recorded
human history can be used to infer climate change in the very recent past.

Contrast icehouse and greenhouse conditions.

Greenhouse climate is warmer than that of today's (especially at the poles), and is
characterized by high atmospheric concentration of carbon dioxide and relatively high sea
level, with no continental glaciers at the poles. In contrast, icehouse conditions are colder,
with permanent ice present at the poles and relatively low levels of atmospheric carbon
dioxide and low sea level.

What are the possible causes of long-term climate change?

a. The sizes and positions of the continents are important. For large continental glaciers
to grow, it is favorable to have large continents in regions near the poles; small continents
bathed in tropical oceans favor greenhouse conditions.
b. Volcanoes emit carbon dioxide, which adds to the greenhouse effect.
c. Uplifted areas are sites of intense weathering, and chemical weathering draws down
atmospheric carbon dioxide.
d. Limestone, coal, organic-rich shale, and oil contain carbon, so when produced in
vast quantities and buried, they keep carbon from reaching the atmosphere as carbon
dioxide. Carbon burial is a check on the greenhouse effect.
e. The appearance or extinction of certain life forms may also impact climate by either
adding carbon dioxide to the atmosphere or removing it.

What factors explain short-term climate change?

a. The abundance of sunspots (cool spots on the surface of the Sun, which may
represent magnetic storms) varies over the course of a decade or so, and may affect total
incident solar radiation. Recently, some researchers have suggested changes in the rate of
influx of cosmic rays may also have an effect.
b. Earth's orbital shape, magnitude of tilt, and direction of tilt vary over Milankovitch
cycles with periods in the tens of thousands of years. These parameters influence whether
glaciers are likely to descend over the continents or melt.
c. Earth's albedo can be increased by an increase in aerosols (such as volcanic ash), cloud
cover, surface ice, or the spread of deserts and grasslands over land that was once forested.
d. Ocean currents may change course, altering the hydrologic system that brings
warmth to some areas and cold, dry conditions to others.
e. Abrupt changes in concentrations of greenhouse gases can also cause short-term
climate change.

Give some examples of events that cause catastrophic change.

Comet or asteroid impact, mass extinctions, explosive or hyperactive volcanism, and
sudden episodes of global warming or cooling can alter climate rapidly with disastrous

Give some examples of how humans have changed the Earth.

Extraction of rock and groundwater, overhunting and overfishing, destruction of forests
and grasslands, and pollution of the air, streams, and oceans have led to subsidence, an
increase in mass wasting, famine, high rates of biotic extinction, acid rain, smog, a hole in
the ozone layer, and so on.

What is the ozone hole, and how does it affect us?

The ozone hole is a large opening in the stratospheric ozone layer over Antarctica (a
smaller hole sits atop the Arctic) caused by the reaction of ozone with anthropogenic

Describe how carbon dioxide-induced global warming takes place, and how humans
may be responsible. What effects might global warming have on the Earth System?

Carbon dioxide is called a greenhouse gas because, much like the glass of a
greenhouse, it allows solar radiation to reach the Earth, but traps the infrared radiation that
the Earth emits to outer space. Because of its relative abundance, carbon dioxide is the most
significant of the greenhouse gases in the atmosphere. Humans are likely responsible for
increased atmospheric carbon dioxide (and resultant greenhouse warming); human burning
of fossil fuels emits carbon dioxide to the atmosphere, and the increase in atmospheric
carbon dioxide over the past two centuries is too rapid to have been caused by geologic
processes. Effects of global warming on the Earth System include sea-level rise, the breakup
of polar ice shelves, the melting of glaciers, a reduction in sea ice formation, shifts in
patterns of precipitation and climate belts, changes in the range distributions of animals,
imperilment of polar wildlife, stronger storms (including hurricanes), and disruption of
oceanic currents (which may bring further climatic change, including the cooling of high

What are some of the likely scenarios for the long-term future of the Earth?

Unless destroyed by impact, Earth will be consumed by the red giant stage of our Sun's
evolution, approximately 5 billion years from now.

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