A 20-Year Dive Into Climate Change History

Here at Science Friday, we’ve been listening to scientists discuss scientific ideas for more than 20 years. In that time, we’ve witnessed many new ideas gain traction in the scientific community. Climate change is one of them. A growing body of evidence suggests that higher levels of atmospheric carbon dioxide—generated from industrialization and pollution from human activities—cause accelerated warming of the planet, leading to more frequent and severe weather events such as hurricanes, heat waves, and blizzards. But why? What evidence supports the notion that climate change might influence severe weather, and how has the media and the scientific community interpreted that evidence?

Weather and climate have always been considered separate, but related. Weather refers to the “short-term conditions of the atmosphere,” and climate refers to “the average daily weather for an extended period of time at a certain location,” according to The National Oceanic and Atmospheric Association. In other words, severe weather events like hurricanes have been considered distinct, short-term blips that do not reflect the larger climate. But, there’s a catch. Now that climate change research has advanced, some members of the scientific community view some weather phenomena as symptomatic of climate change. Not everyone has agreed with this view, however! For a taste of what the dissent has sounded like, listen to this compilation of weather forecaster quotes from 2010:

We invite you and your students to become investigative reporters and probe this question: “Is climate change increasing the frequency and intensity of extreme weather events?” We want you and your students to dive in, and dig deep into a history of interviews and reports from climate change experts over the last two decades. As you go, note how support for the climate change-extreme weather connection shifts.

In addition to this wealth of interviews and reports, we’ve pulled together a note organizer, some activities, interview transcripts, and links to recent climatological data.

Media Resources

Interviews Playlist: What Do Individual Experts Say?

Download of interview excerpts.

Download a zip file of .

Reports: What Do Large Groups of Experts Say?

Browse through excerpts of national and international  from the last 20 years. Each excerpt was chosen because it specifically stated how climate change was expected to influence extreme weather events. Below each excerpt is a short quote from the publisher stating who wrote the report and why it was written.

Tools to Help You Get Started:

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Activities With Your Students

Where Do You Stand?
Is it climate or weather? You decide.

• Have students cut out this list of phenomena (see picture below). Then have them sort through the examples and place them in piles based on whether they represent climate or weather.
• Designate one side of the room as “Weather” and one side as “Climate.” Then go through each example and ask students to stand on one side of the room or the other to indicate if they think the example represents weather or climate, based on their conclusions from the step above. Take this opportunity to ask students to defend their interpretation of each phenomenon to students who chose differently. 
• Repeat this activity after students have listened to the interviews or tried other activities below. The responses might change!

Listening With a Question in Mind:

Does climate change increase the intensity and frequency of extreme weather?

• Make sure that every student has either note-taking materials, or has the  and a pencil.
• Post the following text on a board that can easily be viewed by everyone in the room: “Climate change increases the intensity and frequency of extreme weather.”
• Before listening to the interviews, ask students to imagine that they are interviewing the experts themselves to find out whether the scientific community agrees that climate change increases the intensity and frequency of extreme weather.
• As a whole class or in listening stations, take notes while listening to each interview. Students can listen to them in any order, so long as they keep track of the speaker in their notes. Notes should be concise, accurate, and focus on interviewee responses that address the guiding question.
• After listening to the interviews, ask students to review their notes and decide whether they think the speaker would agree, disagree, or remain undecided about the posted climate change/extreme weather statement, and to justify their decision. 

Traffic Light Opinion:

Would this scientist agree with the statement, “Climate change increases the severity and frequency of extreme weather”?

• This activity is best done shortly after students have listened to an interview and recorded their notes, and can be repeated after each interview.
• Give every student or table group three pieces of paper: one green paper that is labeled AGREES, one red paper labeled DISAGREES, and one yellow paper labeled UNDECIDED.
• As a whole class, have students review their notes from an interview, and ask students to raise their red, green, or yellow cards to indicate whether they think the interviewee would agree, disagree, or remain undecided about the statement.
• For some card raisers, ask them specifically for examples of statements made in the interview that they used to make their decision.
• Repeat this process using the national and international climate change reports. Students can break into groups to divvy up the task of reading the reports. How do these reports differ from individual expert opinions?

Changing Minds Timeline:
How do expert opinions change with time and new evidence?

• This activity is best done with printed-out, after students have listened to some of the interviews and recorded their notes.
• Give each student a collection of six Post-its in red, green, and yellow (or whatever three colors you have available). Green Post-its should be labeled AGREES, red Post-its labeled DISAGREES, and yellow Post-its labeled UNDECIDED.
• Post the following statement at the top of the board: “Climate change increases the intensity and frequency of extreme weather.”
• On a whiteboard or chalkboard, create a timeline that spans from 1990 to 2015, and label each year. As the students listen to the interviews, write the name of the speaker just above the year that corresponds to when the interview was recorded.
• After listening to the interviews, ask students to review their notes and decide whether they think the speaker would agree, disagree, or be unsure about the extreme weather statement posted on the board.
• Invite students to place on each speaker's name a Post-it whose color corresponds to whether or not the speaker would agree with the extreme weather statement. 
• Help students arrange the colors in a way that simulates a histogram, like in the image below. Are there any patterns?
• Repeat this process using the national and international . How do these reports differ from individual expert opinions? How do the reports change over time?

One Quote, One Position:

Choose one quote that represents the speaker or author's opinion about weather extremes and climate change.

• This activity can be done with printed-out and/or with the . Students should work in small groups of two-three students.
• Pass out printed copies of the interview transcripts and reports for students to look over.
• Assign or let students choose an interview or report to explore more deeply. Then give students a chance to discuss and review their notes with each other.
• Ask students to select a single, short quote that most strongly represents the speaker or report author’s point of view on the relationship between extreme weather and climate change.
• Have each student group present their chosen quotes, in order from oldest source to most recent, and ask why they chose them. Do recent quotes differ from older quotes in any noticeable way? What changed over the course of 20 years?
• Do the reports and the experts agree? How do they differ? Have students compare and contrast the quotes from the interviews and those pulled from the climate change reports. Which ones rely on evidence, and which rely on opinion?

Capture the Essence of Opinion:

Artistically represent a perspective from a moment in time.  

• This activity is best done after students have heard some interviews and explored one or more excerpts from the printed-out .
• Separate students into small groups of two-three students.
• Assign or let student groups choose an interview or report to explore more deeply.
• Using highlighters or colored pencils, ask students to underline each of the following in a different color:
  *Uncertainty words and phrases (e.g., may, possible, might, could, perhaps)
  *Rejection words and phrases (e.g., not, won’t, inadequate, insufficient, unlikely, are not expected)
  *Support words and phrases (e.g., will, likely, are expected, is present)
  *One example that shows that weather has changed
  *One reason for uncertainty about future changes in weather
• Individually or in groups, students should draw or paint a collage from the groups of words and phrases they identified.  

Where Are We Now?

The 2014 National Climate Assessment reported that not only are extreme weather events more common, they are more severe. The report also stated that the increase in the number of extreme weather events in recent years is directly related to human-created climate change. The report is presented in a highly accessible website with clear references and data graphics, with a whole section devoted exclusively to extreme weather events. After students have dug deep into historical interviews and climate change reports, invite them to explore the 2014 National Climate Assessment (NCA), while considering the following questions:

• Does the data support that climate change is influencing all types of weather, or just some?
• Which of the 2014 NCA statements about severe weather and climate change would certain interviewees argue with? What are they likely to agree with?
• What gaps in knowledge from the 1990s are resolved in this report?

“Big Picture” Follow-up Questions:

• Do you think an interviewee’s occupation or affiliation might affect his/her perspective on severe weather events and climate change? What about the date of the interview? Why?
• What new technologies helped to provide more evidence to address the connection between climate change and extreme weather?
• Were there types of weather events not addressed in these interviews and reports?
• Which of the interviewees supported their opinion? Who relied on external evidence instead of personal opinion?
• How has scientific consensus about the connection between climate change and extreme weather changed since the 1990s? Why?
• How do these interviews and reports affect your own interpretation of hurricanes, floods, and storms in the face of climate change?

Related Science Friday Video: Sandy's CT Scan and Other Vital Images

Owen Kelley, a research scientist at NASA Goddard, works with data from the TRMM satellite to image the insides of storms. TRMM looked into the eye of Sandy the day before it made landfall and saw something surprising. Satellites also took snapshots of Sandy. J. Marshall Shepherd, president-elect of the American Meteorological Society and the director of the Atmospheric Sciences Program at the University of Georgia, explains some of Sandy's unusual features.

Standards:

Next Generation Science Standards:

• Disciplinary Core Ideas – Global Climate Change (ESSD.3) Though the magnitudes of human impacts are greater than they have ever been, so too are human abilities to model, predict, and manage current and future impacts.
• Scientific Practice 7 – Engaging in Argument from Evidence
• Scientific Practice 8 – Obtaining, Evaluating, and Communicating Information
• Nature of Science – Scientific Knowledge is Open to Revision in Light of New Evidence
   
• MS-ESS3-5 Ask questions to clarify evidence of the factors that have caused the rise in global temperatures over the past century
• HS-ESS3-5 Analyze geoscience data and the results from global climate models to make an evidence-based forecast of the current rate of global or regional climate change and associated future impacts to Earth systems.