Overview: In this activity you will be asked to carefully examine each in a series of graphs. For each graph or pair of graphs, you will be asked to comment on specific questions, and you may also be asked some open-ended questions such as what observations you have. For each question, think carefully about your answer. Then fill out your answers in pencil, in the spaces provided. When you are finished, discuss your answers with your groupmates. If your discussion leads you to want to change your answer or add to it, do so. Only when everyone in your group is done filling out your answers to the questions and graphs on the page(s) you have, you are to come up to the front and collect the next page(s) for this activity. Proceed in this way until you come up and receive the last handout of graphs and questions.
Directions for Part I.
There are two graphs (labeled A and B) for part I. Examine each of
them carefully, following the general directions in the Overview, and
record your answers below.
Examine Graph I, part A and answer these questions based on graph A:
i. What pattern(s) persist over time, regardless of year?
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ii. What is not repeating but instead changing from year to year?__________________________
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iii. At roughly what value do you expect the black line to be in
Jan/Feb 2008?___________(include units)
Now examine graph B in part I and address the following:
i. In what year were you born? _____ (*) At roughly what level was
mean carbon dioxide at the Mauna Loa Observatory that year?
_____(*). What units go with this number? _____ and
ii. What year was the older of your two parents born? _____ (‡) At roughly
what level was mean CO2 at the observatory that year?
_____ (‡).
iii. Roughly, what is the average rate of change
between the (‡) year and the (*) year? Answer:_____ppm per year.
Roughly what was the average rate of change between the (*) year
and 2008? _____ ppm per year.
iv.Overall, what "story" or "stories" do the two graphs in Part
I. tell? If you were writing a newspaper paragraph
summarizing only what the data shows (i.e. skip
eye-grabbers, policy recommendations, etc; describe
the facts in specific, but plain English) what might you write
about what the data depicted above shows?
iv. What is the difference between the red (here, grey) line and black line? What
do you think the "dots" on the lines mean? Which of the preceding
represent actual readings from scientific instruments?
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v. What does a newspaper mean reporting an all-time record reading of "ppm of CO2", and how does that differ from an end-of-year story on the record-breaking) level of CO2 "for 2007" being higher than past years' levels?
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| B. | 
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Now examine the graph II. below. What "story" does this
graph tell about
the data collected by climate scientists?
More specifically, what information does this graph contain that
the preceding graphs did not contain? What does it tell us about
"recent times" versus "previous centuries"? When does change occur?
What event(s) in human history might correspond to this? Does it tell
us anything about rates of change? What are some other factors, if
any, which you notice?
By the way, why does the slope of the graph, during those years
corresponding to the 310-380ppm range, look different in graph II.?
Is there more? Yes, but only after writing down your full
answers (after discussions with your group) should you pick up the
next handout (page) of this in-class exploratory activity...
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II.
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| III. | 
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1. What "story" does graph III tell? What
is new (or different here as compared with the previous graphs?
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2a. How can you explain how the far right of this graph looks, and why it
appears so strikingly different from the right hand side of the
previous graphs? b. What do you see in the y-axis scale?
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What is
the significance of "1800"? Pre-1800, is there a lower/upper range of
y-axis value? Other thoughts?
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Is there more to the story than even shown by all the previous
graphs together? Examine graph IV below:
Being as specific, careful, and precise in your language, what new
feature(s) is brought to the surface and to our attention
by this graph, which was not apparent from any
of the preceding graphs? What might be significance be of this feature(s)? If the "bottom" of the semi-regular cycles is about 190ppm and the
top is about 295ppm, then over the past 400,000 years the "range" is
about _____ppm. What would the ppm level need to be, to be above the
top of this (pre-1800AD) 400,000 year range, by as many ppm as
the top of the range is above the bottom of the range? _________
(include units).
Roughly when will this milestone be reached if 2008's annual mean was
about 385pm and if global annual-average CO2 reading end up
rising at 2ppm/yr as some models suggest will happen? _________.
In how many years will the "point of Dangerous Climate Change" be
reached, at present rates of ppm increase, if the danger point is
[You will have noticed that the above graphs do not
show "global temperature" alongside CO2 concentrations. Since the
mathematics and quantitative literacy (rather than the latest
scientific findings) are the focus of this course, many "details" --
which are important to our planet's environment and future -- are
beyond the scope of what we can discuss in class. However there is a
Blog run by a group of working scientists (peer-reviewed climate
scientists) at RealClimate.org which has some background on how
temperature and CO2 relate. In a nutshell, asking "Which caused
which?" is the wrong question since it is both true that higher
temperatures can cause increases in CO2 and higher levels of
CO2 contribute to higher temperatures. In fact, this kind of
"feedback" loop or vicious circle is a big concern about CO2 and
other GHGs (greenhouse gasses). There is more to the story, see for
example
http://www.realclimate.org/index.php/archives/2007/04/the-lag-between-temp-and-co2/
which might be useful to you either for your class projects, for
future courses in environmental issues, or for your future as an
informed citizen].
Worth 1000 Words? Questions for homework
1. Please summarize: What have you learned about "scales" of graphs?
Which graphs are most helpful for answering which kinds of questions?
What types of questions are not easily answerable in one graph (which?
name its Roman numeral) but easier to answer with another graph
(which?)
2. The next time you see a graph whose independent variable is "Time" and
whose dependent variable ("y"-axis variable) is some environmental
quantity, what are some questions that you might want to ask about it?
What other graphs might you want to see to better understand what is
going on?
3. Do any of these insights apply also to the use of graphing calculators?
4. What are some lessons (a) when we see a graph in a newspaper article?
(b) When we see two graphs side by side? (c) When you are trying to
compare (or just reconcile)
two graphs about the same quantity, which appear in different articles?
5. Look at the image:
http://en.wikipedia.org/wiki/File:Carbon_Dioxide_400kyr.png
Look at it carefully and answer: why is the red line, which is more
visible and "larger" than the black and cyan colored parts of the
enlarged graph inset, actually less visible than the black and cyan
portions on the full graph?
A. "How do we know that recent CO2 increases are due to human
activities?" At http://www.realclimate.org/index.php?p=87
(Remember "Carbon-14 dating"? Here isotopes are used in another way)
Optional Supplemental Reading, cont.
Curious what CO2 levels were even earlier than 400,000 years ago?
As of 2005-2006 new research was able to finally answer this question:
B. "CO2 'highest for 650,000 years'"
At http://news.bbc.co.uk/2/hi/science/nature/4467420.stm
(24 November 2005)
"We find that CO2 is about 30% higher than at any time, and methane
130% higher than at any time; and the rates of increase are absolutely
exceptional: for CO2, 200 times faster than at any time in the last
650,000 years."
C. "Deep ice tells long climate story"(September 4, 2006)
At http://news.bbc.co.uk/2/hi/science/nature/5314592.stm
D. For a graph of CO2 atmospheric levels going back 650,000
years, see
Remember Graph I.A.? It was created by the National Oceanic and
Atmospheric Administration (NOAA) for August 2007. Curious what things
looked like much more recently? See the link below. Before you do,
look one last time at the graph I.A...can you visually guess what the
graph is likely to look like by 2009? Did you mentally visualize it?
Ok, now see:
http://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2_trend_mlo.png
(actually that's Mauna Loa observatory, slightly different
from gml.noaa.gov/webdata/ccgg/trends/co2_trend_gl.png
which is global average of many observatories.
IV.
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•At 400ppm? In _____ years.
•At 450ppm? In _____ years.
•At 425 ppm? In _____ years.
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(Backup:
http://barzilai.org/courses/105e/hw/wk4.Carbon_Dioxide_400kyr_Rev.png)
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Optional Supplemental Reading
"Over a five year period commencing in 1999, scientists working with
the European Project for Ice Coring in Antarctica (Epica) have drilled
3,270 meters into the Dome C ice, which equates to drilling nearly 900,000
years back in time"
"Carbon dioxide levels are substantially higher now than at any time
in the last 800,000 years, the latest study of ice drilled out of
Antarctica confirms."
