ATMO 336 – Spring 2009
Exam 3
Name__________________________
Multiple Choice Section (3 points each)
Mark final answers on the multiple choice answer sheet. Please mark your answers clearly.
You must turn in the entire exam when finished.
1. In comparing the temperature climatologies between Tucson and San Diego, which city has the larger
temperature standard deviation (or variability) in all seasons of the year?
(a) Tucson
(c) Both cities have about the same standard deviation
(b) San Diego
(d) There is no way to determine an answer to this question
2. Suppose the average surface temperature in some regionally-defined climate zone goes up by 2° C in
the next 100 years. Which conclusion is most sensible?
(a) Such a small change cannot have much impact on the life living in that climate zone.
(b) The change could significantly impact the life living in that climate zone since the probability
of extremely hot temperatures in that climate zone may increase sharply.
(c) An increase of 2° C in the average temperature would almost certainly cause the current
ecosystem in that climate zone to collapse.
3. Which of the following is true?
(a) Your body is continuously emitting infrared radiation.
(b) Your skin effectively holds in radiation to keep you warm.
4. The largest part of the radiation energy emitted by the Sun is which type of radiation?
(a) Microwave
(b) Visible
(c) Infrared
(d) Ultraviolet
5. Currently the Planet Earth reflects about 30% of the radiation energy that it receives from the Sun.
What if the Earth were to become cloudier and reflected away 35% of the Sun’s radiation energy that
hits the planet. Which of the following MUST be true?
(a) The average surface temperature of the Earth would become higher.
(b) The average surface temperature of the Earth would become lower.
(c) The radiative equilibrium temperature for the planet Earth would become higher.
(d) The radiative equilibrium temperature for the planet Earth would become lower.
6. Which gas is the largest contributor to the greenhouse effect on Earth?
(a) Nitrous oxide (N2O)
(c) Water vapor (H2O)
(b) Methane (CH4)
(d) Carbon dioxide (CO2)
7. Most of the photons emitted from the surface of the Earth (land surface and oceans) ______ .
(a) are reflected back to the surface by atmospheric gases and clouds
(b) are absorbed by atmospheric gases and clouds
(c) go directly off into outer space
8. Even with worldwide concern about global warming and conservation efforts, we have not seen a
reduction in the rate at which CO2 and other greenhouse gases are being emitted into the atmosphere
by human activities.
(a) True
(b) False
9. Fact: Chlorofluorocarbons (CFCs), which are manmade chemicals, were shown to destroy ozone in
the stratosphere and are potent greenhouse gases. Fact: The developed countries of the world have
stopped producing CFCs and now use alternative, ozone-friendly chemicals to replace the use of
CFCs. Question: Do the CFC substitutes act as greenhouse gases?
(a) Yes
(b) No
10. Most climate models predict that by the year 2100, the Earth’s global average temperature will
increase somewhere in the range of _________ assuming the current rate of greenhouse gas emissions
continues.
(a) (1 – 4) C
(b) (6 - 10) C
(c) (10 – 15) C
(d) (40 - 50) C
11. Consider the following sequence of events:
 Humans add greenhouse gases to the atmosphere
 Surface temperature warms
 The summer growing season is extended (longer) in the middle and high latitude regions of
Earth
 With the longer growing season, plants in the middle and high latitudes take in more carbon
dioxide from the atmosphere
This is an example of a ___________ process in the climate system.
(a) negative feedback
(b) positive feedback
12. Suppose the amount of CO2 in the atmosphere becomes twice what it was prior to the Industrial
Revolution. Ignoring all feedbacks, how would this increase in CO2 act to change the global average
surface temperature of the Earth?
(a) The global average surface temperature would increase
(b) The global average surface temperature would decrease
(c) The global average surface temperature would not change
(d) There is no way to determine how global average surface temperature would change
13. Climate models have been used to run simulations for doubled CO2. The models do include some
feedback processes. The overall feedback effect with respect to changes in global average surface
temperature that is simulated by most current climate models is _______ .
(a) negative, i.e., the surface temperature change is smaller than the non-feedback case
(b) positive, i.e., the surface temperature change is larger than the non-feedback case
(c) neutral, i.e., the surface temperature change is the same as the non-feedback case
14. With regard to the carbon cycle, respiration and decay by land-dwelling organisms is a __________
for carbon stored in the atmosphere.
(a) source
(b) sink
15. The problem of the “missing carbon dioxide sink” is best described by which of the following
statements?
(a) There is less CO2 in the atmosphere than expected.
(b) There is more CO2 in the atmosphere than expected.
(c) The reserves of fossil fuels are less than expected.
(d) The reserves of fossil fuels are greater than expected.
16. Compared to 100 years ago, today the world’s oceans ________________ .
(a) take in more carbon dioxide from the atmosphere
(b) take in less carbon dioxide from the atmosphere
(c) take in about the same amount of carbon dioxide from the atmosphere
17. Assuming that global warming does occur, the one side effect (of the choices given) that we are most
certain about is ______________ .
(a) the number of hurricanes will increase
(b) farming production in the U.S. will decline (too hot), but farming production in Canada and
Russia will increase (longer growing season).
(c) tropical diseases will spread further north and south away from the equator
(d) sea level will rise
Shown above are two different reconstructions of past changes in global average temperature over
the last 1000 years. Both were discussed in lecture. Use this figure to answer questions 18 and 19.
18. Which reconstruction is known as the “hockey stick” reconstruction?
(a) The one on the left side
(b) The one on the right side
19. Which reconstruction would more likely lead one to connect the modern warm period to human
emissions of greenhouse gases?
(a) The one on the left side
(b) The one on the right side
20. Global average surface temperatures from 1995 through today have been warmer than any other 14
year period since 1860. This statement is _______________ .
(a) almost certainly true
(b) believed to be true by many people, but it is difficult to back up with evidence
(c) not true; It is a scare tactic used by those who warn about the evils of modern society
21. The 2007 IPCC report concludes with 90% certainty that most of the measured increase in global
average surface temperature has occurred due to anthropogenic emissions of greenhouse gases. The
major supporting evidence for this claim is provided by computer models of climate.
(a) True
(b) False
22. Climate change has occurred throughout Earth’s history. However, due to greenhouse gas emissions,
the global average temperature today is higher than at any other time in Earth’s history.
(a) True
(b) False
23. Consider the following:
 1st OBSERVATION: since 1860, the 13 warmest years in terms of global average
temperature have occurred since 1995.
 2nd OBSERVATION: greenhouse gas concentrations are higher today than at any time since
1860, mainly due to fossil fuel burning and deforestation.
 CONCLUSION: the above observations show that the warm conditions since 1995 have
been totally caused by our emissions of greenhouse gases into the atmosphere.
Which is the BEST interpretation of the above?
(a) The first observation is incorrect, therefore the conclusion is flawed
(b) The second observation is incorrect, therefore the conclusion is flawed
(c) Both observations are correct but the conclusion cannot be proven at this time
(d) Both observations are correct and therefore the conclusion is correct
24. Which association is INCORRECT?
(a) The Younger-Dryas shows that large fluctuations in climate can occur over short time periods
(less than 100 years).
(b) During the Medieval warm period, Vikings established agricultural colonies on Greenland.
(c) The Little Ice Age was just as cold as the last true ice age that ended about 15,000 years ago,
but only lasted a few decades.
(d) During the Holocene maximum, North Africa probably received much more rainfall and the
Nile River carried much more water than today.
Figure for short answer question 3b
Instructions for short answer section. Questions begin on the back of this page.
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Everyone must answer question 1.
For questions 2 – 4, you must select and answer either (a) or (b).
Each answer is worth 8 points. The short answer section has 32 possible points.
Write your answers on the lines provided for the short answers. Make sure you
answer all parts of each question you select.
 Your answers should be short and to the point. Points may be deducted for
incorrect or unnecessary statements in your answer, even if the correct answer is
found somewhere.
1.
The following excerpts were taken from a 2007 TIME Magazine article titled “Global Warming: What Now?”
“And make a mess we have [done]. If droughts and wildfires, floods and crop failures, collapsing climate
sensitive species and the images of drowning polar bears didn’t quiet most of the remaining [human-caused]
global-warming doubters, the hurricane-driven destruction of New Orleans did.”
“Now it is getting pretty hard to deny [that these events have resulted from human emissions of greenhouse
gases]. Atmospheric levels of CO2 were 379 parts per million in 2005, higher than at any other time in the past
650,000 years.”
Do events like wildfires, droughts, floods, and Hurricane Katrina provide good evidence that the Earth’s
climate is becoming more hostile in recent years considering that no mention is made about the frequency
and severity of historical weather disasters? Explain. Does a recounting of recent weather-related
disasters together with the assertion that CO2 levels are the highest in 650,000 years make it “hard to
deny” that the recent disasters have resulted from human activities? Explain.
2.
Select (a) or (b)
a. Clouds have both a warming and a cooling influence on the surface temperature of the Earth. Explain
how clouds act to cool the surface temperature of the Earth. Explain how clouds act to warm the
surface temperature of the Earth. As climate changes, the amount of cloud cover will likely change
as well. The overall effect on the Earth’s surface temperature depends on the type of cloud. Here we
compare two types of clouds: high, cold clouds and low, warm clouds. The table below describes the
radiation properties of each cloud type compared to clear sky conditions. An increase of which type
of cloud would most likely lead to higher surface temperatures? Explain. (Hint. The surface
temperature warms in response to how much solar radiation energy it absorbs. The surface
temperature cools in response to how much infrared radiation energy is emitted to outer space.
Cloud Type
High, cold clouds
Low, warm
clouds
b.
3.
Absorbed solar radiation energy at
surface
30% less compared to clear sky
conditions
85% less compared to clear sky
conditions
Infrared radiation energy emitted to outer space
70% less compared to clear sky conditions
10% less compared to clear sky conditions
In answering this question, assume that the rise in global average temperature since 1980 has
definitely been caused by increases in greenhouse gases due to human activity. An environmental
group proposes that the world set a goal to reduce greenhouse gas emissions back down to what they
were in the year 2000 by the year 2025. A spokesperson for the group states that if this goal could be
met we will begin to see (1) a reduction in greenhouse gas concentrations in the atmosphere by 2050,
and (2) a downward trend in global average temperature by 2050. Explain why both of the
spokesperson’s projections are flawed. To receive full credit, you must provide more than one
reason for why the projections would be incorrect. Remember your answer should be consistent
with the assumption given in the first sentence.
Select (a) or (b)
a. As part of the carbon cycle, the ocean surface waters contain a reservoir of carbon in the form of
dissolved carbon dioxide. Carbon is exchanged between the atmosphere and the ocean surface waters.
The amount of dissolved carbon dioxide that the ocean waters will hold depends on two variables as
follows: (a) the higher the concentration of carbon dioxide in the atmosphere, the more carbon dioxide
that will be dissolved in the ocean and (b) the higher the temperature of the ocean water, the less
carbon dioxide that will be dissolved in the ocean. Briefly explain whether the processes (a) and (b)
described above will be positive or negative feedbacks with respect to possible global warming
caused by human burning of fossil fuel?
b.
In the documentary “An Inconvenient Truth”, Al Gore uses the correlation between past temperature
changes and carbon dioxide concentrations in the atmosphere as inferred from ice core data (see graphs
on page 4 of this exam) as evidence to make the prediction that because we have caused carbon
dioxide levels to be 385 ppm today (off scale on the graph below), there is no doubt that global average
temperature will rise to be off the chart as well. What is wrong with using this correlation as
evidence for Al Gore’s prediction?
4.
Select (a) or (b)
a. How is the global average surface temperature today different from what it was in 1900 (overall
change)? Describe in more detail how the global average temperature has changed between 1900
and today. You should mention three specific time periods in your answer. For each of the three
time periods, indicate whether or not they support the claim that temperature changes since
1900 are directly related to the concentration of greenhouse gases in the atmosphere. Briefly
explain your answers.
b.
In the class lecture pages it is written “The next 30 years or so may help us better determine what is
most responsible for modern climate change. There are quite a few researchers predicting a decadeslong period of global cooling …”. Explain how the observed changes in global average
temperature over the next 30 years may help to better determine a reason for modern climate
changes. Will 30 years of warming absolutely prove that greenhouse gases are causing the
modern warming? Will 30 years of cooling absolutely prove that greenhouse gases are not
causing the modern warming? Briefly explain your answers to the last two questions.