Scientific Evidence for Anthropogenic Climate Change

Nicole Wigder

Overview

This module provides students with the opportunity to read and synthesize information from published IPCC reports. Students are asked to choose a topic to focus on and present the information. This is designed to be a culminating project for high school students. Created by Nicole Wigder (2012), updated by Surabhi Biyani (2019). 

Focus Questions

  1. How have people influenced the Earth’s climate?
  2. How has our understanding of anthropogenic climate change shifted over time?
  3. How certain are we that anthropogenic climate change is occurring?

Learning Goals

  1. Read and understand scientific reports
  2. Write a research report with citations
  3. Develop expertise in a climate change topic
  4. Present research results visually and orally

Background Information

  • For this project, students will create a consensus scientific report similar to the Climate Change Assessment Reports developed by the Intergovernmental Panel on Climate Change (IPCC).
  • Each of the five assessment reports represents the scientific consensus on climate change at the time the reports were written (AR1: 1990; AR2: 1995; AR3: 2001; AR4: 2007; AR5: 2014).
  • The five assessment reports, along with other IPCC reports, are located on the IPCC website: https://www.ipcc.ch/reports/
  • The students will need to cite sources in their research papers. The IPCC reports are written using citations, so they provide a good example to students on how to cite sources.
  • We recommend that the students use APA style citations, since there is a lot of background information about this style on the Purdue OWL website (http://owl.english.purdue.edu/owl/resource/560/1/).

Materials

  • Access to the internet and word processing software
  • Materials to create poster or video presentations of the research

Procedure

The following procedure is a suggestion that includes ideas from teachers participating in the 2011 UWHS/NASA Climate Science Workshop.  Other options and suggestions for modifying the procedure are listed below.  Overall, we recommend that teachers modify the student instructions/expectations based on what fits best with their class.

  1. The students will work in groups of 3-4. Each group will pick a climate research topic from the provided list.
  2. Each group will read the assigned reading for their topic and write an 8-10 page research report.
    • The assigned reading includes excerpts from each of the four IPCC assessment reports. Therefore, it will give the students perspective on how scientific understanding of their topic has changed over time.
    • The groups should write a first draft of the report and get comments from another group and/or the teacher before turning in the final draft.
    • After finishing the reports, each group will prepare a poster describing the main points from their paper.
  3. At the end of the unit, each group will present their topic to the rest of the class using their poster. (This is very similar to a poster presentation at a scientific meeting.)  Presentations should be about 20 minutes, with 10 additional minutes for discussion.
    • The discussion will be led by the students and should focus on further scientific research that should be done on the topic. The group presenting should take notes on what the class decides.
  4. Finally, the class will compile its consensus report on climate change. This could be a binder with a page for each topic.  Each topic’s page would include the abstract copied from the students’ paper and a bulleted list of the future research ideas brainstormed by the class.

Other options and suggestions for modifying this procedure:

  1. Grading could be mostly focused on the consensus report and presentation, with the full report just graded for completeness.
  2. Students could be required to find and read 1-2 additional papers or articles outside of the assigned reading.
  3. It was suggested that students could take field trips to shadow scientists at their work.
  4. If more than one school is working on the project at the same time, it was suggested that it would be educational to bring all the students together for the presentations, to make the experience more like a scientific meeting.
  5. It was also suggested that UW graduate students might volunteer to “grade” or provide feedback on the poster presentations.
  6. During the 2012 school year, one teacher implemented this project in his class. He had each group pick one of the topics and create a video or give a PowerPoint presentation on their topic, in addition to turning in a written report.  (And, many of the students prepared AMAZING videos!)

Instructions for Students

Introduction

Your goal is to research a climate change topic and how scientific understanding of that topic has changed over time.  You will work with a group to write a research paper about your topic and create a poster presentation similar to the posters that scientists prepare for research conferences.  You will present your poster to the rest of the class and then lead a discussion about your topic.  You will use the results of this discussion to write a summary of your topic that will be included in a class consensus report on climate change.

Research Paper Instructions

The research topic list includes required reading for each topic.  The required reading includes background information on your topic as well as excerpts from the four Intergovernmental Panel on Climate Change (IPCC) assessment reports, which are known as AR1, AR2, AR3, AR4, and AR5.  Each of the assessment reports summarizes the scientific consensus on climate change at the time the report was written.  The reports were written in 1990 (AR1), 1995 (AR2), 2001 (AR3), 2007 (AR4), and 2014(AR5).  The sixth assessment report, AR6, is scheduled to be completed in 2022.  By reading the portions of each assessment report that focus on your topic, you will be able to explore how the scientific consensus on your topic has changed over time.

Each member of your group should read all of the assigned reading materials.  You will probably need to read all of the materials more than once in order to fully investigate the differences between the four assessment reports.  You can also choose to read additional documents related to your topic that you find in the library or online.  Be careful with information you find online.  It is important to only consult websites from reputable sources, such as government agencies or universities.  There may be abbreviations or words that you do not understand in the documents that you are reading.  Take time to look up the definitions online or in the IPCC AR5 glossary (https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_AnnexIII_FINAL.pdf).  If you don’t know what an abbreviation stands for, look at the pages before your assigned reading section to find the meaning of the abbreviation.

Your group will write an 8-10 page double-spaced paper on your topic.  This is a research paper, which means that it should include scientific citations.  This means that every fact or statistic you write should be attributed to the source where you found the information.  You’ll notice that the IPCC reports contain citations; use these reports as an example of how frequently you should be citing sources in your own paper.  In your paper, cite only the four IPCC assessment reports (not the papers that are cited in these reports) and the other websites or documents that you have read.  You will be using the APA citation style (http://owl.english.purdue.edu/owl/resource/560/1/).  You don’t need to follow all of the paper formatting requirements listed on this website, but you do need to follow the guidelines for in-text citations (http://owl.english.purdue.edu/owl/resource/560/03/) and writing out the reference list at the end of your paper (http://owl.english.purdue.edu/owl/resource/560/08/ or http://owl.english.purdue.edu/owl/resource/560/10/).  Hint: treat the IPCC assessment reports as books with ‘IPCC’ as the author.

You can use abbreviations in your paper, but you have to define them the first time you use the abbreviation.  For example:

“There are no ice shelves in the mainland United States (US), but there are ice shelves in the Arctic and Antarctica.  The US assists other countries with research on these ice shelves.  This research is documented in the Intergovernmental Panel on Climate Change (IPCC) assessment reports.  The IPCC reports are written by US scientists in collaboration with scientists of other nationalities.”

Your paper should have five sections in the following order:

Abstract: The abstract is a one paragraph summary of your entire paper.  Even though it is located at the beginning of your paper, you should write this section last.

The abstract should include: (1) 1-2 sentences introducing your topic and why it’s related to climate change, (2) 1 sentence describing each of the results detailed in the ‘Scientific Consensus Over Time’ section, (3) 1-2 sentences explaining the main results in the ‘Scientific Certainty’ section, and (4) 1-2 sentences describing your main conclusions.  The abstract should be no more than 1000 words long.

Introduction: The introduction should provide background information on your topic.  When writing this section, pretend that your audience doesn’t know anything about your topic.  Provide a lot of details about your topic and explain why it is related to anthropogenic climate change.  This section should be 2-4 paragraphs.

Scientific Consensus Over Time: This should be the longest section of your report, covering 4-6 pages.  Show in detail how the scientific consensus on your topic has changed over time by describing the differences between the information in the four IPCC assessment reports.

To do this, make a list of main concepts related to your topic.  For example, if your topic is stratospheric ozone, your list of main concepts could be: (1) Arctic stratospheric ozone, (2) Antarctic stratospheric ozone, (3) seasonal variations in stratospheric ozone, (4) stratospheric ozone concentrations in the future, and (5) methods for measuring stratospheric ozone.  Next, write a paragraph about each of these concepts explaining how the scientific consensus changed over time.  For some of the concepts you choose, the earlier assessment reports will have no information about the concepts.  This is not a problem; just make sure to document in your paper that the scientific community didn’t have a consensus on the topic until the later assessment reports.

Scientific Certainty: In this section of your report, describe the amount of scientific certainty about your subject, focusing on the information in the IPCC AR5 report.  For example, you could focus on answering some of the following questions:

  • How sure is the scientific community about the future trends related to your topic?
  • Are there multiple explanations for what is occurring now or what will occur in the future?
  • When you look at the graphs of data related to your topic, how large are the error bars?
  • When statistics are quoted in AR5, what is the uncertainty in these numbers (what is the number after the ± sign)?

Conclusions: This 1-2 paragraph section should provide a broad overview of the main ideas detailed in your paper.  For example, you could focus on answering some of the following questions:

  • In general, how has scientific consensus on your topic changed over time?
  • Is there more information on your topic now than there was in the past?
  • In general, what are the future trends related to your topic and what is the uncertainty in those predictions?
  • Are there areas where further research is needed?

References: This section should include the full citations for all of the sources you cited in your paper.  See: http://owl.english.purdue.edu/owl/resource/560/08/ and http://owl.english.purdue.edu/owl/resource/560/10/).  There should be a citation for each of the IPCC reports and for each of the other documents or websites you read.

Poster Instructions

After you finish the research paper, your group should prepare a poster summarizing the main points of your paper.  You will use the poster to present your topic to the rest of the class.  Be creative in how you present the information and make sure to include lots of pictures and graphs.  If you include any of the graphs or pictures from the IPCC reports or other online sources, make sure to cite the source of those graphics on the poster.  (For example, write (IPCC AR4, 2007) next to a plot copied from the fourth IPCC assessment report.)  At a minimum, your poster should contain: a title, your names, background information on your topic, the main points from the ‘Scientific Consensus Over Time’ and ‘Scientific Certainty’ sections of the report, and the main points from your ‘Conclusions’ section.

Presentation Instructions

Your group will have approximately 30 minutes to present your topic to the rest of the class.  During the first 20 minutes, describe your topic to the class and point to the relevant graphs or pictures on your poster as you describe them.  During the final 10 minutes, you must lead the class in a discussion about what concepts around your topic need further research in the future.  Ask the class questions like, “what concepts are least clear or least certain about this topic?” or “do you have ideas about what other information scientists need to better understand this topic?”.  There are no wrong answers!  Take notes on the ideas that the class comes up with, because you’ll need these to write your section of the class consensus report.

Consensus Report Instructions

Each group will contribute a 1-2 page summary of their topic for the class consensus report.  Use the provided template to create your summary for the consensus report.  There are two main sections of the summary: (1) the abstract, which is exactly the same as the abstract in your research report, and (2) a bulleted list of areas of future research on your topic, which should be a summary of the ideas brainstormed by the class during your presentation.  Each bullet should be 1-2 sentences describing the area of future research and why it is important.

Potential Research Topics

Below is a list of potential research topics.  Included with each topic is a list of articles and websites that you must read if you choose the topic.  The five IPCC assessment reports can be found on the following websites:

  1. Sea ice: explore the relationship between temperature and sea ice extent in the Arctic and Antarctic.
    • Background information
      • Read all of the information in the sea ice section of the National Snow & Ice Data Center website (http://nsidc.org/cryosphere/seaice/).  (Start on the ‘Introduction’ page. Keep reading until you have reached the end of the ‘Studying: Modeling’ page.)
    • IPCC AR1
      • Section 7.8.2 (Sea-ice extent and thickness)
    • IPCC AR2
      • Section 3.2.5.3 (Sea ice extent and mass)
    • IPCC AR3
      • Section 2.2.5.2 (Sea ice extent and thickness)
    • IPCC AR4
      • Section 4.4 (Changes in sea ice), including sub-sections 4.4.1-4.4.4.3.
    • IPCC AR5
      • Section 4.2 (Sea Ice)
  1. Sea level change: explore the connection between climate change and sea level.
    • Background information
      • Read section 5.5.1 (Introductory Remarks) in IPCC AR4.  This section explains that there are two major processes affecting sea level change.  Next, read about each of the processes in section 5.5.3 (Ocean Density Changes) and 5.5.5 (Ocean Mass Changes), including sub-sections 5.5.5.1-5.5.5.4.
    • IPCC AR1
      • Section 9.3 (Has Sea Level Been Rising Over the Last 100 Years?), including sub-sections 9.3.1-9.3.3.
      • Section 9.5 (How Might Sea Level Change in the Future?), including sub-sections 9.5.1-9.5.2.
    • IPCC AR2
      • Section 7.2 (How Has Sea Level Changed Over the Last 100 Years?), including sub-sections 7.2.1-7.2.2.
      • Section 7.5 (How Might Sea Level Change in the Future?), including sub-sections 7.5.1-7.5.5.
    • IPCC AR3
      • Section 11.3 (Past Sea Level Changes), including sub-sections 11.3.1-11.3.3.
      • Section 11.5 (Future Sea Level Changes), including sub-sections 11.5.1-11.5.4.3.
    • IPCC AR4
      • Section 5.5.2 (Observations of Sea Level Changes), including sub-sections 5.5.2.1-5.5.2.6.
      • Section 5.5.6 (Total Budget of the Global Mean Sea Level Change). Also, read Frequently Asked Question 5.1 (Is Sea Level Rising?).
    • IPCC AR5
      • Section 13.2 (Past Sea Level Change), including subsection 13.2.1.
      • Section 13.3.6 (Budget of Global Mean Sea Level Rise).
      • Section 13.5 (Projections of Global Mean Sea Level Rise).
  1. Atmospheric carbon dioxide: explore the relationship between carbon dioxide and atmospheric temperature.
    • Background information: Read section 1.2 (Carbon Dioxide) in IPCC AR1, including sub-sections 1.2.1-1.2.1.3. In IPCC AR4, read Frequently Asked Question 2.1, including Box 1: “What is Radiative Forcing?”
    • IPCC AR1
      • Sub-sections 1.2.4.1-1.2.4.3 within section 1.2.4 (The Contemporary Record of Carbon Dioxide- Observations and Interpretation).
      • Section 1.2.6 (Sensitivity Analyses for Future Carbon Dioxide Concentrations).
    • IPCC AR2
      • Sub-sections 2.1.1-2.1.3.2 within section 2.1 (CO2 and the Carbon Cycle).
    • IPCC AR3
      • Sub-sections 3.5.1-3.5.2 within section 3.5 (Observations, Trends and Budgets).
      • Section 3.7.3.2 (Concentration projections based on IS92a, for comparison with previous studies).
    • IPCC AR4
      • Section 2.3.1 (Atmospheric Carbon Dioxide).
    • IPCC AR5
      • Section 8.3.2.1 (Carbon Dioxide).
  1. Atmospheric methane: explore the relationship between methane and atmospheric temperature.
    • Background information
    • IPCC AR1
      • Section 1.3 (Methane), including sub-sections 1.3.1-1.3.5.
    • IPCC AR2
      • Section 2.2.2.1 (Methane).
      • Section 2.2.3.1 (The methane budget).
    • IPCC AR3
      • Section 4.2.1.1 (Methane).
    • IPCC AR4
      • Section 2.3.2 (Atmospheric Methane).
    • IPCC AR5
      • Section 8.3.2.2 (Methane).
  1. Ocean heat content: explore the role that ocean heat content plays in changes to the Earth’s climate.
    • Background information
    • IPCC AR1
      • Section 7.7 (Sub-Surface Ocean Temperature and Salinity Variations).
    • IPCC AR2
      • Section 3.2.4 (Subsurface Ocean Temperatures).
    • IPCC AR3
      • Section 2.2.2.5 (Sub-surface ocean temperatures and salinities).
    • IPCC AR4
      • Section 5.2.2 (Ocean Heat Content), including sub-sections 5.2.2.1-5.2.2.3.
    • IPCC AR5
      • Section 3.2 (Changes in Ocean Temperature and Heat Content), including sub-sections 3.2.1 – 3.2.5.
  1. Atmospheric aerosols: explore the relationship between aerosols and atmospheric temperature.
    • Background information
    • IPCC AR1
      • Section 2.3.2 (Direct Aerosol Effects)
      • Section 2.3.3 (Indirect Aerosol Effects)
    • IPCC AR2
      • Section 2.3 (Aerosols), including sub-sections 2.3.1-2.3.4.
    • IPCC AR3
      • Section 5.1 (Introduction), including sub-sections 5.1.1-5.1.2.
    • IPCC AR4
      • Sub-sections 2.4.1-2.4.3 of section 2.4 (Aerosols).
    • IPCC AR5
      • Section 7.3 (Aerosols).
  1. Glaciers: explore the relationship between temperature and glacial retreat.
    • Background information
      • Read the National Snow & Ice Data Center website (http://nsidc.org/cryosphere/glaciers/).  Focus on the information in the ‘Introduction’, ‘The Life of a Glacier’, ‘About Glaciers’ and ‘Photo Gallery’ sections of this website.  (Start on the ‘Introduction’ page.  At the end of each page, there is a link for the next page of information.  Keep reading until you have reached the end of the ‘Drumlins’ page.)
    • IPCC AR1
      • Section 7.8.3 (Land Ice).
    • IPCC AR2
      • Section 3.2.5.1 (Retreat of glaciers).
      • Section 7.3.2 (Glaciers and Ice Caps), including sub-sections 7.3.2.1-7.3.2.3.
    • IPCC AR3
      • Section 2.2.5.4 (Mountain glaciers).
    • IPCC AR4
      • Section 4.5 (Changes in Glaciers and Ice Caps), including sub-sections 4.5.1-4.5.3.
    • IPCC AR5
      • Section 4.3 (Glaciers), including sub-sections 4.3.1-4.3.3.
  1. Ocean salinity and circulation: explore the salinity of Earth’s oceans and how salinity changes can affect ocean circulation, especially in the Atlantic Ocean.
    • Background information
    • IPCC AR1
      • Section 7.7 (Sub-Surface Ocean Temperature and Salinity Variations).
    • IPCC AR2
      • Section 3.4.3 (Northern Hemisphere Circulation).  When reading this section, just focus on the part that discusses the North Atlantic Oscillation (NAO).
    • IPCC AR3
      • Section 7.3.7 (Thermohaline Circulation and Ocean Reorganisations).
    • IPCC AR4
      • Section 5.2.3 (Ocean Salinity).
      • Section 5.3.2 (Atlantic and Arctic Oceans).
      • Sub-section 5.3.2.1 (North Atlantic Subpolar Gyre, Labrador Sea and Nordic Seas).
      • Box 5.1 (Has the Meridional Overturning Circulation in the Atlantic Changed?)
    • IPCC AR5
      • Section 3.3 (Changes in Salinity and Freshwater Content).
      • Section 3.6 (Changes in Ocean Circulation).
  1. Tropical cyclones: explore recent changes in the tropical cyclones (a category that includes hurricanes).
    • Background information
    • IPCC AR1
      • Section 7.11.3 (Tropical Cyclones).
    • IPCC AR2
      • Section 3.5.3.1 (Tropical cyclones).
    • IPCC AR3
      • Section 2.7.3.1 (Tropical cyclones).
    • IPCC AR4
      • Section 3.8.3 (Evidence for Changes in Tropical Storms), including sub-sections 3.8.3.1-3.8.3.6.
      • Box 3.5 (Tropical Cyclones and Changes in Climate).
    • IPCC AR5
      • Section 2.6.3 (Tropical Storms).
      • Section 14.6.1 (Tropical Cyclones).
  1. Extreme temperature and precipitation events: explore changes in temperature and precipitation in recent years.
    • Background information
      • Section 3.8.1 (Background) of the IPCC AR4.
    • IPCC AR1
      • Section 7.11.2 (Droughts and Floods).
    • IPCC AR2
      • Sub-sections 3.5.2.1-3.5.2.2 in section 3.5.2 (Climate Variability).
    • IPCC AR3
      • Sub-sections 2.7.2.1-2.7.2.1 in section 2.7.2 (Is There Evidence for Changes in Variability or Extremes?)
    • IPCC AR4
      • Section 3.8.2 (Evidence for Changes in Variability or Extremes), including sub-sections 3.8.2.1-3.8.2.2.
      • Frequently Asked Question 3.3 (Has there been a Change in Extreme Events like Heat Waves, Drought, Floods and Hurricanes?)
    • IPCC AR5
      • Section 2.6.2 (Temperature Extremes).
      • Section 2.6.2.1 (Precipitation Extremes).
      • Frequently Asked Questions 2.2 (Have there been any changes in climate extremes?)
  1. Oceanic dissolved carbon: explore the connection between anthropogenic carbon emissions and oceanic dissolved carbon.
    • Background information
    • IPCC AR1
      • Sub-sections 1.2.4.2 (Uptake by the ocean).
    • IPCC AR2
      • Sub-sections 2.1.4-2.1.5 within section 2.1 (CO2 and the Carbon Cycle).
    • IPCC AR3
      • Section 3.2.3 (Ocean Carbon Processes), including sub-sections 3.2.3.1-3.2.3.3.
    • IPCC AR4
      • Section 5.4.2 (Carbon), including sub-sections 5.4.2.1-5.4.2.4.
    • IPCC AR5
      • Section 3.8.1 (Carbon), including sub-sections 3.8.1.1-3.8.1.2.
Attribution:  Wigder, Nicole. “Scientific Evidence for Anthropogenic Climate Change” Climate Science for the Classroom edited by Bertram and Biyani, 2019. https://uw.pressbooks.pub/climate/chapter/scientific-evidence-for-anthropogenic-climate-change/  Date of Access.