Tools and Methods in Environmental Science: Ice Cores

Emma Sevier, University of Puget Sound; Penny Rowe, NorthWest Research Associates; and Steven Neshyba, University of Puget Sound
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Summary

Students gain experience with tools and methods of Environmental science through exploring the paleoclimate record using ice cores as climate proxies. They learn what causes natural climate change and how it is recorded in ice cores, exploring glacial-interglacial cycles and correlations between carbon dioxide and temperature in the past million years, using ice core data.

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Learning Goals

Students gain basic computing skills through completing a tutorial to familiarize themselves with coding in Python and working through a scaffolded Jupyter Notebook. Students learn about ice cores and how they provide a record of climate change. They download and analyze ice core data (oxygen isotope or δ18O records) and convert δ18O values in the 40,000-year record to temperature estimates. Critical thinking and active inquiry is promoted by open-ended responses to prompts (Pause for Analysis questions). Specific learning goals are as follows:

  1. Understand how ice cores record past temperature.
  2. Learn how to download and interpret ice core data.
  3. Recognize Milankovitch Cycles, Dansgaard Oeschger Events, and glacial interglacial periods in ice core data.
  4. Understand the nature of correlations between CO2 and temperature in the past million years.

Context for Use

This activity is designed to be used in a lower-level general Environmental Science or Tools and Methods in Environmental Science course. Students must have in-class access to computers with internet access and with Jupyter Notebook installed. A computer lab with pre-loaded software can be used or, as in successful pilots, students can download the software onto personal laptops before class (instructions are provided). Problems can be mitigated by having students work in pairs and having an extra laptop or two available as needed, equipped with the software. The activity has successfully been taught during class in a course with 10 students but would be suitable for up to 30 students in a class or lab setting. Application in large classes can be fostered by additional support, if available; e.g. through teaching assistants. The activity typically takes 4 to 5 hours and includes homework assignments. No previous computational or coding experience is required. The instructor will give an introductory lecture to the thermodynamic concepts, assign pre-module homework, guide the students in working through the module, and facilitate group discussions. The module is adaptable – either of three parts can be used or modified, as has been done for a lower-level Engineering Physics course.

Description and Teaching Materials

Overview

In this module, students will work actively with polar data through computer programming in Jupyter with Python. The instructions and notebook are designed so that no prior coding experience is necessary on the part of the student or instructor. The notebook and all other materials needed to implement the activity are provided below. Digital backups of data used are included in case online data is moved or removed. The following describes materials, instructor preparation, and the workflow of student activities.

Take a quick look at how the Ice Core module looks in Jupyter. (Please note that this produces a static image that is not rendered perfectly. It's meant as a quick overview. For the interactive version, see the instructions and materials below).

Materials

  • Student setup guides (Zip Archive 1.2MB Apr29 20). After unzipping, this includes:
    • finding_moving_files_mac.docx, finding_moving_files_pc.docx: File management on your computer
    • installing_running_jupyter_mac.docx, installing_running_jupyter_pc.docx
    • Introduction_to_python3.ipynb: Python3 tutorial, to be run in Jupyter Notebook
  • Student materials (Zip Archive 374kB Apr29 20): After unzipping, this file contains:
    • IceCoreModule.ipynb: The Jupyter Notebook for students to work through
    • co2.png, domefuji.txt, grip.txt: Ancillary files that need to be in the same directory as the Notebook
  • Presentation: Climate change on a geologic time scale (PowerPoint 2007 (.pptx) 20.7MB Mar28 20)
  • :
    • IceCoreModule_key.ipynb: Completed Jupyter Notebook
    • co2.png, domefuji.txt, grip.txt: Ancillary files that need to be in the same directory as the Notebook
    • IceCore_answers_rubric.docx: Answers to questions and rubric.
  • Digital backups (Zip Archive 676kB Apr27 20)
    • CO2_concentration_2020_03_08.pdf, CO2_concentration_2020_03_08.png
    • edc-co2-2008.txt
    • summit_station_weather_2020_03_08.png

Instructor Preparation

  1. Download the materials above and unzip all zipped files.
  2. Work through the student tasks in the workflow below.
  3. Compare the completed notebooks to the provided keys and read the question answers in the rubric (see Assessment).
  4. Modify the notebooks as desired and/or include only a portion of them.

Workflow

  1. Students work through the setup guides. They follow the instructions for installing Jupyter on a Mac or PC and work through Introduction_to_python3.ipynb in Jupyter. (Alternatively, the instructor ensures the software is available in a computer lab that will be used.)
  2. Students then follow instructions for finding and moving files on a Mac or PC. These tasks have been found to bog down class time for students who are not experienced in them, so we suggest assigning them as homework and reserving some class time afterward to follow up as needed.
  3. The instructor makes the Student Materials available to students on the platform used by their institution. To use the files in Jupyter, students will need to keep these files together in a directory.
  4. The instructor gives students a presentation on climate change on a geologic time scale (PowerPoint 2007 (.pptx) 20.7MB Mar28 20) and how ratios of stable isotopes of oxygen can serve as a temperature proxy.
  5. Students watch two videos about ice cores: Ice Core Secrets Could Reveal Answers to Global Warming from Science Nation (5 minutes) and Ice Core Record of Climate from NOVA (3 minutes).
  6. Students read the article Ice Cores and Climate Change from the British Antarctic Survey.
  7. Students start Jupyter and open IceCoreModule.ipynb. They read the introduction and define the vocabulary terms: climate proxy, stable isotope, Milankovitch Cycles, Dansgaard Oeschger events.
  8. Working at a computer singly or in pairs, students complete IceCoreModule.ipynb. The instructor walks around the class, helping as needed.
  9. After students wrap up, the class meets as a group to discuss student responses to the Pause for Analysis questions (see rubric provided in Assessment section below for answers) as well as any observations or questions.
  10. The instructor wraps up the activity by linking the student work back to the original goals.

Teaching Notes and Tips

Digital Backups

As part of completing the module (step 10 above), students will download or look at data on the Internet. Data archived online is sometimes moved or removed, or students may have difficult accessing it. In case of this possibility, digital backups are included: Digital backups (Zip Archive 676kB Apr27 20). We suggest downloading these files and having them available (e.g. on a thumb drive) in case they are needed. The zip file includes the following files:

  • EPICA Dome C Ice Core 800KYr Carbon Dioxide Data: edc-co2-2008.txt
  • CO2 concentration: CO2_concentration_2020_03_08.pdf, CO2_concentration_2020_03_08.png
  • Summit weather: summit_station_weather_2020_03_08.png

Computer lab vs personal laptops

While students can use a computer lab or work on individual laptops, we suggest the latter. Installing Jupyter Notebooks on laptops is straightforward, gives the students a valuable experience, and allows them to complete work at home, if needed. Furthermore, the student has the computational tool available to them after completion of the activity.

Assessment

Successful completion of the CGI module is expected to be indicative of meeting the learning objectives. Assessment includes in-class assessment of the module as students work as well as grading of completed notebooks and Pause for Analysis responses.

, as a completed Jupyter Notebook.

: although suggested scores are given for all questions, the instructor may choose to grade only selected questions.

References and Resources

Climate change videos:

  • Climate Change: Lines of Evidence, from the National Academies of Science, Engineering and Medicine. Options include a 26 minute video or any of 7 videos of about 4 minutes each. To allow for varying levels of available class time, video content was ranked as follows, from most to least relevant:
    • Chapter 1: From the 18 second mark to the 1 minute mark
    • Chapter 3
    • Chapter 5 (8 minutes total).
    • Chapters 1-5 (about 20 minutes).

References

  • Jupyter
  • Python version 3
  • References and resources contained within the Jupyter Notebook, permafrost.ipynb, include figures from the literature as well as use of web sites and are attributed within the notebook.