ATMS 111
HW #4 – Due Thursday, 08/15/13
Name: _____Solutions_________________________
Question 1 (1)
True or False: The measured global warming trend in the past century of 0.8 C has a significant
contribution from the urban heat island effect. ____False__________
Question 2 (2)
Isotopes of the same element have different:
Select one:
a) number of protons
b) atomic mass
c) number of electrons
d) number of neutrons
e) both (b) and (d)
Question 3 (2)
Name three “proxies”, or indicators that are used to infer past temperature and precipitation:
Tree rings, ice cores, rocks, ocean sediment cores, fossils, to name a few
Question 4 (2)
Does “ocean acidification” mean that the ocean will become an acid? Why or why not?
No, the ocean is a base, so acidifying the ocean just means it will lower the pH (become
more acidic), but it is not likely to become an acid (a pH lower than 7).
Question 5 (2)
A possible explanation for the change from global dimming to global brightening in the 1990s is:
a) Variability in the sun
b) Melting of sea ice
c) The reduction of aerosols as cars and industry became more clean
d) Reforestation occurred rather than deforestation
Question 6 (4)
a. What effects do volcanic eruptions have on climate on short timescales and why?
On short timescales, a volcanic eruption has a cooling effect because it emits sun-blocking
or reflecting particles like sulfate aerosols, dust, and ash, which stay in the atmosphere only
a short time (1-2 years at most).
b. What effects do volcanic eruptions have on climate on long timescales (>100,000 yrs) and
why?
On long timescales, volcanic eruptions have a warming effect on climate. This is because they
emit the greenhouse gas carbon dioxide, which stays in the atmosphere a very long time
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ATMS 111
HW #4 – Due Thursday, 08/15/13
scales (>1,000 years for some of it). Carbon dioxide emitted from volcanoes can build
up in the atmosphere on very long timescales, causing the planet to warm.
Question 7 (10)
a. What was the carbon dioxide concentration of the atmosphere the year you were born? Find
this out by researching online (NOAA Earth System Research Laboratory might be a good place
to start). Year born: _1976_______ CO2 concentration: _331.66___ppm
b. What is the current carbon dioxide concentration? __397.23___ ppm
c. What information did you use? (what website and figure? Is it annual mean CO2 or a certain
month? Global mean CO2 concentration or a certain station?)
I used NOAA ESRL annual average CO2 data at the Mauna Loa station for the years 1977 and
2011, given in a table linked from here:
http://www.esrl.noaa.gov/gmd/ccgg/trends/#mlo_data
d. By how much has the CO2 concentration in the atmosphere risen since you were born? (show
your work) ___65.57__ ppm
397.23 ppm - 331.66 ppm = 65.57 ppm
e. How much does that mean the CO2 concentration rose on average each year during that
period? (show your work) __1.77___ ppm/yr
65.57 ppm / 37 years = 1.77 ppm/yr.
f. During the most recent glacial cycles the CO2 concentrations usually increase from about 180
ppm to 280 ppm over more like 10,000 years. At what rate did CO2 change then? (show your
work) __0.01_ ppm/yr
(280-180) ppm / 10,000 yr = 100 ppm / 10,000 yr = 0.01 ppm/yr
g. How does this rate compare with what you got in part (e)?
The glacial rate is over two orders of magnitude slower than todayʼs. Todayʼs rate is 170
times faster!
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ATMS 111
HW #4 – Due Thursday, 08/15/13
h. You should have found that the rate in part (e) is much greater than the rate in part (f). Do
you think this distinction is important to make when thinking about global warming impacts?
Why or why not?
I think this is a very important distinction to make because it is the rate of change that really
affects ecosystems and living things. Changes that are too fast prohibit species from adapting
and threaten their existence.
Question 8 (2)
Why is biking from East to West (or West to East) in Seattle really difficult? What made it this
way? (Use the Puget Sound topographic images from the paleoclimate lecture to help you).
During the last glacial maximum about 21,000 years ago, the Cordillera ice sheet advanced
and then retreated from north to south in this region. This caused glacial striations in the
land, which appear as steep hills and ridges oriented North-South, making it hard to bike
from East to West and vice versa.
Question 9 (2)
Snowball Earth is a phrase used to describe:
a) The last glacial maximum 21,000 years ago
b) Europa, a frozen moon of Jupiter
c) The time about 700 million years ago when Earth was glaciated near the equator at
sea level
d) The scene in New York City during the movie "Day after Tomorrow"
Question 10 (4)
a. True or False: When Earth becomes primarily ice covered, it is very hard to melt the ice
because once it spreads down to a certain latitude, a runaway ice-albedo feedback cools
the planet way down. __True__________
b. True or False: During a snowball Earth period, CO2 will start to rise again because
volcanism continues to emit CO2, while chemical weathering can’t remove CO2 from the
atmosphere because the land is covered in ice. __True____________
c. True or False: During a snowball Earth period, as soon as CO2 concentrations start rising
again, the ice will immediately start to melt and a runaway ice-albedo feedback will rapidly
warm the planet. __False______________
d. True or False: Despite the high likelihood that Earth was completely or very nearly
completely covered by ice about 700 million years ago, it is believed that primitive life
survived and multi-cellular life developed soon after. _True___________
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ATMS 111
HW #4 – Due Thursday, 08/15/13
Extra Credit (+5): Find a current news article related to global warming and write a paragraph
summary of the article. In your summary, relate what you have learned in class so far to what
you learned from the article. (Include either a link to the article here, or a printed copy of it,
along with your summary)
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