Eileen Herrstrom

University of Illinois at Urbana-Champaign

Undergraduate class on introductory physical geology or quantitative reasoning for non-majors

Must know basic information about climate change, both past (Pleistocene) and present, and be able to use Microsoft Excel to create and format charts

This is a laboratory activity that follows lectures on ice ages and climate change. It is the fourteenth and last lab exercise in the course.

Examine historical measurements of temperature and graph temperature anomalies, analyze and interpret data related to the sunspot cycle and total solar irradiance, and compare solar activity and atmospheric composition to the global temperature record

Calculate rates of change for carbon dioxide through time, compare the patterns of carbon dioxide increase, solar activity, insolation, and the global temperature record, and determine which variable best accounts for the observed increase in mean annual global temperature

Analyze maps of Arctic sea ice extent and regional sea level rise, summarize variations in carbon dioxide concentrations and global temperatures, synthesize and interpret the data from this activity in a short essay

Thermometers similar to modern mercury instruments were invented in the 1600s, and people began to measure air temperatures almost immediately. The longest continuous record of average monthly temperatures extends from 1659 to the present for an area in central England.

A few other places hold intermittent records almost as old, but more widespread and regular temperature measurements did not become common until the 1880s. A temperature record spanning 100-300 years may seem like a large data set, although it is only a small fraction of Earth's history. The instrumental record is, however, long enough to reveal a trend, which has been called by various names: climate change, global warming, climate chaos, or "global weirding."

Student materials for this exercise include a Microsoft Excel spreadsheet with data on historical sunspot cycles, the instrumental temperature record, and carbon dioxide concentrations through time. A separate file holds student instructions and questions. The exercise is divided into three parts.

Part I introduces the concepts of energy from the Sun and global temperature anomalies. Students create and format a chart of temperature anomalies and compare it with both a graph of temperature values and a graph of sunspot cycles. This section also illustrates how to make a chart on one worksheet using data on another worksheet.

In Part II, students work with greenhouse gas data. After a quick look at the history of climate science, students study CO2 concentrations obtained from ice cores and, more recently, direct measurements. They calculate rates of change, compare CO2 and methane, and try to relate temperature changes to changes in insolation, sunspot activity, and CO2.

Part III involves visiting the NASA Climate Time Machine. This website contains four sets of images illustrating historical sea ice, temperature and CO2 changes and projections of future sea level changes. After answering several questions about the images, students write a short essay assessing the evidence for anthropogenic climate change.

In both the traditional face-to-face and online versions of the course, this activity is assessed based on the answers to the questions and on the final essay. It is also possible to have students submit their completed spreadsheets, although this option works best in a small class.

Gilbert N. Plass, G. N., J.R. Fleming and G. Schmidt, 2010, American Scientist Classics: Carbon Dioxide and the Climate: American Scientist, vol. 98, no. 1, pp. 58-67.
https://www.americanscientist.org

The NASA Climate Time Machine, 2018: Online resource – Accessed 17 June 2019
https://climate.nasa.gov/interactives/climate-time-machine/

Data sources:

Global Mean Estimates based on Land and Ocean Data, 2019, National Aeronautics and Space Administration: Online resource – Accessed 17 June 2019. https://data.giss.nasa.gov/gistemp/graphs_v3/

Etheridge, D.M., L.P. Steele, R.J. Francey, and R.L. Langenfelds, 1998, Atmospheric methane between 1000 A.D. and present: evidence of anthropogenic emissions and climatic variability: Journal of Geophysical Research, 103, 15979-15996. Online resource – Accessed 17 June 2019
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/law/law2006.txt

CO2 expressed as a mole fraction in dry air, 2019, National Oceanographc and Atmospheric Administration. Online resource – Accessed 17 June 2019. ftp://aftp.cmdl.noaa.gov/products/trends/co2/co2_annmean_mlo.txt

Berger ,A., and M.F. Loutre, 1991, Insolation values for the climate of the last 10 million years, Quaternary Sciences Review, V. 10 N. 4, pp. 297-317. Online resource – Accessed 17 June 2019
https://doi.pangaea.de/10.1594/PANGAEA.56040?format=html#download

Sunspot Index and Long-term Solar Observations, 2019, SDC-SILSO, Royal Observatory of Belgium, Brussels. Online resource – Accessed 17 June 2019
http://www.sidc.be/silso/datafiles