Student Assignment
WHAT CAN MAUNA LOA TELL US ABOUT CLIMATE CHANGE?
CO2 Collection, Analysis and History
Excerpts from Money for Keeling: Monitoring CO2 Levels, by Spencer Weart
(http://www.aip.org/history/climate/Kfunds.htm)
“An example of what climate scientists went through to push their research forward, and how that changed over time, is the struggle for money to monitor carbon dioxide gas (CO2). Measurements of the level of the gas in the atmosphere would turn out to be of profound interest for the future of the world. But at the outset, nobody thought the problem was particularly pressing. Early studies of CO2 in the atmosphere were strictly a matter of satisfying general scientific curiosity, and their funding came from the usual sources for university research. An individual would work on CO2 for a few months, supported on his salary as a professor, with perhaps a little help from a government grant awarded mainly for other matters. No wonder, then, that in the 1950s researchers lacked what they needed most and what some were beginning to call for, reliable measurements of how much CO2 was in the atmosphere.
The problem was highlighted at a conference in Stockholm in 1954. The conference's goal was a practical one: to discuss how the atmosphere carried around gases that crops needed to grow, such as nitrogen and CO2. The participants agreed that there ought to be a network of stations to provide regular data on such gases. They thought priority should go to CO2, not least because it might alter the climate. Heeding the call, educational institutions allocated some money and set up a network of 15 measuring stations throughout Scandinavia. Their measurements of CO2 fluctuated widely from place to place, and even from day to day, as different air masses passed through. That might be of interest to meteorologists and agriculture scientists, but it was useless for global warming studies. "It seems almost hopeless," one expert confessed, "to arrive at reliable estimates of the atmospheric carbon-dioxide reservoir and its secular changes by such measurements..."
Charles David (Dave) Keeling, a postdoctoral student at the California Institute of Technology, thought he could do better. Underlying his interest was a personal drive. Keeling was a dedicated outdoorsman, spending all the time he could spare traveling woodland rivers and glaciated mountains, and he chose research topics that would keep him in direct contact with wild nature. Monitoring CO2 in the open air would do just that. Keeling's case was not an unusual example of crucial "support" provided for geophysics from simple love of the true world itself. On lonely tundra or the restless sea, when scientists devoted their years to research topics that many of their peers thought of minor import, part of the reason might be that these particular scientists could not bear to spend all their lives indoors. Yet their research sometimes turned out to be more significant than even they had hoped.
Just at this time, however, planning was underway for an International Geophysical Year. Scientists and governments organized the IGY in response to a combination of altruistic and Cold War motives, ranging from a hope to promote international cooperation to a quest for geophysical data of military value. The project would extract a large if temporary lump of new money from the world's governments. Greenhouse gases like CO2 were too low on the list of IGY concerns to be allocated much support, but with so much money now available, a little might be spared…”
Keeling’s research led to the “Keeling Curve,” a cornerstone of Climate Change science.
“The “Keeling Curve” of CO2 measured at Mauna Loa, Hawaii over nearly half a century. Within the long-term rise are annual fluctuations as Northern Hemisphere plants take up carbon during summer growth and release it in winter decay.” (http://www.aip.org/history/climate/xMaunaLoa.htm)
http://scrippsco2.ucsd.edu/program_history/keeling_curve_lessons.html
How were the Mauna Loa data collected?
Used with permission of Dr. Karen Bice. Original information can be found at http://www.whoi.edu/science/GG/people/kbice/maunaloa_text.pdf
From Dr. Karen Bice, Woods Hole Oceanographic Institute:
The following description of methodology is modified from the CDIAC web address given above. See the original source for references and more detail.
Methods
The Mauna Loa Observatory, Hawaii, is located near the summit of the active Mauna Loa volcano, 19°32' N, 155°35' W, 3397 m above mean sea level. You can view photos of the facility at http://www.mlo.noaa.gov/. Air samples at Mauna Loa are collected continuously from air intakes at the top of four 7-m towers and one 27-m tower. Four air samples are collected each hour for the purpose of determining the CO2 concentration. Determinations of CO2 are made by using a Siemens Ultramat 3 nondispersive infrared gas analyzer with a water vapor freeze trap. This analyzer registers the concentration of CO2 in a stream of air flowing at ~0.5 L/min. Every 30 minutes, the flow is replaced by a stream of calibrating gas or "working reference gas". In December 1983, CO2-in-N2 calibration gases were replaced with the currently used CO2-in-air calibration gases. These calibration gases and other reference gases are compared periodically to determine the instrument sensitivity and to check for possible contamination in the air-handling system.
Hourly averages of atmospheric CO2 concentration, wind speed, and wind direction are plotted as a basis for selecting data for further processing. Data are selected for periods of steady hourly data to within ~0.5 parts per million by volume (ppmv); at least six consecutive hours of steady data are required to form a daily average. The Mauna Loa atmospheric CO2 measurements constitute the longest continuous record of atmospheric CO2 concentrations available in the world.
The Mauna Loa site is considered one of the most favorable locations for measuring undisturbed air because possible local influences of vegetation or human activities on atmospheric CO2 concentrations are minimal and any influences from volcanic vents may be excluded from the records. The methods and equipment used to obtain these measurements have remained essentially unchanged during the 46-year monitoring program.
Because of the favorable site location, continuous monitoring, and careful selection and scrutiny of the data, the Mauna Loa record is considered to be a precise record and a reliable indicator of the regional trend in the concentrations of atmospheric CO2 in the middle layers of the troposphere.
Student Assignment
WHAT CAN MAUNA LOA TELL US ABOUT CLIMATE CHANGE?
CO2 Collection, Analysis and History
Read the excerpt and answer the following questions
1. How did the focus on CO2 research change since the 1950’s? (four different changes)
2. Choose one of your answers from question one and explain why you think that focus from the 1950’s did not support sound scientific research.
3. The excerpt states that the Keeling Curve shows annual fluctuations (higher and lower shifts) in the CO2 level at Mauna Loa, Hawaii (in the Northern Hemisphere.) What causes that fluctuation?
4. On the following chart, draw a line that represents the cycle of the fluctuations of the CO2 level at Mauna Loa.
Higher CO2 levelLower CO2 level
spring summer fall winter
Student Assignment
WHAT CAN MAUNA LOA TELL US ABOUT CLIMATE CHANGE?
Comparing CO2 Data by Location
Graph 1 Annual data trends
1. Graph the 1985, 1990, 1995, 2000 and 2005 annual average data for each location A-F.
2. Draw a best-fit straight line on the trend of each location.
3. Look at the line for each location:
Do you see any trends at each location? If so, what?
Do you see any worldwide trends over time? If so, what?
4. Using the data, what is your projection of what the Average Annual CO2 level will be at each location in 2007?
Graph 2 Monthly data trends
5. Graph the monthly data for 1985, 1990, 1995, 2000 and 2005 at each location. Clearly mark the year and location of each line. It is helpful to color key each location. Each location might also be graphed separately.
6. Assess the shapes of each location’s lines.
Are there locations that seem to have similar shapes?
7. Discuss the causes of rising or falling CO2 and what you think might be the cause of changes at each of the graphed locations.
8. Using the World map worksheet and your knowledge of the causes of the rise and fall of CO2, decide which of the 6 boxes on the map might be the locations of each of the data sets (A-F)
Location Data:
For each table: Values are taken from a curve consisting of 4 harmonics plus a stiff spline and a linear gain factor, fit
to monthly concentration values adjusted to represent 2400 hours on the 15th day of each month. Data used to
derive this curve are shown in the accompanying graph. Units are parts per million by volume (ppmv) expressed
in the 2003A SIO manometric mole fraction scale. The "annual average" is the arithmetic mean of the twelve
monthly values.
Location A
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann. Ave.
1985 342.44 342.60 342.82 342.88 343.17 343.66 343.99 344.26 344.20 343.91 343.91 343.96 343.48
1990 350.58 350.71 350.91 350.96 351.26 351.75 352.09 352.37 352.33 352.03 352.03 352.07 351.59
1995 356.79 356.95 357.18 357.27 357.59 358.12 358.51 358.84 358.84 358.60 358.66 358.76 358.01
2000 365.71 365.85 366.04 366.07 366.34 366.79 367.10 367.34 367.27 366.97 366.96 367.02 366.62
2005 375.01 375.23 375.50 375.65 376.03 376.61 377.04 377.41 377.43 377.21 377.26 377.37 376.48
Location B
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann. Ave.
1985 348.37 348.77 349.27 350.24 350.45 348.48 344.28 340.66 341.33 344.56 347.04 348.46 346.83
1990 356.36 356.83 357.37 358.41 358.64 356.59 352.22 348.45 349.20 352.61 355.24 356.75 354.89
1995 362.62 363.13 363.73 364.86 365.15 363.06 358.53 354.64 355.45 359.04 361.80 363.39 361.28
2000 371.59 372.06 372.65 373.75 373.95 371.64 366.85 362.79 363.64 367.35 370.18 371.81 369.86
2005 381.20 381.77 382.45 383.70 384.05 381.80 376.93 372.76 373.70 377.67 380.75 382.56 379.95
Location C
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann. Ave.
1985 350.11 344.04 337.99 338.49 343.09 347.36 350.04
1990 359.12 359.79 360.24 360.45 360.64 358.78 352.52 346.31 346.80 351.51 355.88 358.63 355.89
1995 364.49 365.31 365.88 366.24 366.57 364.80 358.52 352.28 352.87 357.75 362.27 365.12 361.84
2000 373.78 374.58 375.16 375.48 375.77 373.83 367.33 360.97 361.59 366.51 371.05 373.90 370.83
2005 383.23 384.09 384.71 385.10 385.47 383.64 377.11 370.62 371.27 376.38 381.14 384.17 380.58
Location D
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann. Ave.
1985 344.33 344.30 344.07 343.80 343.74 343.91 344.16 344.34 344.45 344.63 344.99 345.42 344.35
1990 352.16 352.15 351.93 351.69 351.66 351.86 352.13 352.32 352.44 352.61 352.95 353.36 352.27
1995 358.86 358.90 358.72 358.51 358.51 358.73 359.00 359.18 359.28 359.44 359.76 360.14 359.09
2000 367.53 367.43 367.11 366.78 366.68 366.82 367.05 367.22 367.33 367.50 367.85 368.27 367.30
2005 376.99 377.04 376.88 376.70 376.75 377.04 377.39 377.68 377.90 378.17 378.61 379.11 377.52
Location E
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann. Ave.
1985 345.99 347.01 347.70 348.71 349.39 348.22 345.53 342.81 341.72 342.82 344.80 346.16 345.91
1990 354.85 355.92 356.62 357.67 358.36 357.20 354.49 351.75 350.67 351.80 353.82 355.20 354.86
1995 361.15 362.21 362.91 363.95 364.64 363.44 360.68 357.91 356.86 358.07 360.19 361.66 361.14
2000 370.05 371.17 371.94 373.04 373.73 372.48 369.65 366.84 365.77 367.00 369.14 370.61 370.12
2005 379.88 381.01 381.77 382.88 383.63 382.40 379.55 376.69 375.63 376.94 379.21 380.80 380.03
Location F
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average
1985 344.97 346.00 347.43 348.35 348.93 348.25 346.56 344.68 343.09 342.80 344.24 345.55 345.90
1990 353.66 354.70 355.39 356.20 357.16 356.23 354.82 352.91 350.96 351.18 352.83 354.21 354.19
1995 359.97 361.00 361.64 363.45 363.79 363.26 361.90 359.46 358.05 357.76 359.56 360.70 360.88
2000 369.14 369.46 370.52 371.66 371.82 371.70 370.12 368.12 366.62 366.73 368.29 369.53 369.48
2005 378.37 379.69 380.41 382.10 382.28 382.13 380.66 378.71 376.42 376.88 378.32 380.04 379.67
What can Mauna Loa teach us about climate change?
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Graph 1
Label each axis, include units
Comparing Carbon Dioxide by Location380
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What can Mauna Loa teach us about climate change?
Name______
Graph 2
Title your graph. Label each axis, include units
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World Map Worksheet