How Can You Use Persuasion Theory to Present a Thought-Provoking Climate Change Speech?

Denali glaciers melting, National Park Service

Climate change caused by human activity is about as close to a scientific certainty as you get, but people argue about it anyway. Well, to be perfectly clear, the scientific community doesn’t argue about it much, but politicians and the public rage and rage.

Climate change speakers love to tell people that evidence for climate change exists, but they hardly ever tell people what the evidence is. Asking people to accept a controversial point on faith only gets you so far.

So—let’s make a stab at how to persuade climate change skeptics. I talked about climate change and persuasion theory last time. This post puts that theory into practical action. Let’s review the points to consider:

First, long-lasting attitude change occurs only when the audience thinks about the topic.

Second, speakers must give supporting information. Do you expect people to take your word for stuff? There’s not a chance that will work. Don’t be silly.

Third, speakers need to make it easy for audiences to think carefully. You can’t make the opposite mistake and spew out incomprehensible facts, complicated figures, and obscure technical terms. Help the audience understand what you’re saying.

Got it? Sounds simple enough, doesn’t it? But persuasive speaking requires lots of effort. You can’t just say that “almost all climate scientists believe in climate change” unless you also say something specific about the evidence behind their belief. You can’t even say the scientists agree about climate change unless you give evidence to show that they agree. For example, thousands of scientific studies show that fossil fuels are causing climate change. But you can’t just say, “there are thousands of studies.” Too vague! Not convincing. A skeptic will tune you out. You need to state and prove the facts.

Try this, which you might say early in a climate change speech (my imaginary speech is in boldface type): 

A research team led by John Cook of the University of Queensland looked at more than 4000 published scientific studies about the causes of climate change. They agreed that “The consensus that humans are causing recent global warming is shared by 90%–100% of publishing climate scientists according to six independent studies by co-authors of this paper.”  They also found that most disagreement about climate change comes from people who are not climate science experts. That’s right, the controversy isn’t coming from the people who know the most about climate.

The United Nations international study panel, which studied the work of scientists all over the world, showed that greenhouse gases have increased greatly during our industrial age. They found that “The atmospheric concentrations of the greenhouse gases carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) have all increased due to human activity.” They add that “In 2011 the concentrations of these greenhouse gases were 391 ppm, 1803 ppm, and 324 ppm and exceeded pre-industrial levels by about 40%, 150%, and 20%, respectively.” 

That states points in the speaker’s words but gives the audience some specifics in the source’s exact words. It cites sources. Next, we need to put the specifics in understandable terms. Our imaginary speech continues: 

In other words, today, there is about 2/5 more carbon dioxide in the air than a couple hundred years ago. The AAAS Climate Science Panel points out that there is “overwhelming evidence of human-caused climate change” that shows “significant costs and extraordinary future risks to society.” 

Climate change deniers love to say that carbon dioxide levels vary due to natural causes. That’s true to some extent, but it’s not happening to this degree. So, you need to pre-empt that argument: 

Scientists have taken ice core samples going back 800,000 years. Carbon dioxide levels are the highest now that they have been in all that time—more than ¾ of a million years. Satellite observations have also shown that solar radiation is actually a bit less in recent decades. Taken together, those facts pretty much prove that the levels we have now are not natural. 

Turning the tables on climate change deniers is another good idea. Many conservatives think that university professors and the United Nations are a bunch of left-wing conspiracy artists. But how can they argue with the energy companies themselves? It turns out that big energy companies know all about climate change; they just lie about it. Let’s continue our imaginary speech: 

Finally, although the oil, gas, and coal industries have shoved climate change denial down the public’s throats, it recently turned out that Exxon knew in 1982 or even earlier that oil burning caused climate change. This was proven by their own documents. Exxon even conducted climate change studies on one of its tankers, the Esso Atlantic. In fact, in 1977, James Black, an Exxon scientist, told his own company this: “In the first place, there is general scientific agreement that the most likely manner in which mankind is influencing the global climate is through carbon dioxide release from the burning of fossil fuels.” 

End with a brief summary to help the audience remember the key points they need to think about: 

So, let’s put it like this: climate change is real. Scientists have proven that the main cause is the burning of oil, coal, and gas. The amount caused by burning these fuels is far greater than anything that nature has been doing for the last several hundred thousand years. Although they’ve lied about it, Exxon has known this for years and their own documents prove it. 

Of course, that’s not as flashy as Greta Thunberg. So, let’s end our imaginary speech by coming back to Thunberg to give her the credit she deserves: 

Greta Thunberg is right. It’s time to believe the scientists. She said, “How dare you!” She was right. Her critics are wrong. Let’s get this done while there is still time. 

So, use principles of persuasion. Give facts. Restate the facts in terms that ordinary people can understand. Cite your sources. Relate facts to common experiences that people share. To pre-empt the climate change deniers, refute the wrong arguments that you know they have in their minds. Since Exxon and other big energy companies know that climate change is real, go ahead and quote them. Climate change deniers aren’t foolish enough to think that Exxon is part of a left-wing Deep State conspiracy. And, for crying out loud, be careful with scientific jargon and esoteric abbreviations. Avoid needless technical terms and define any terms that you do need to use.

Long-term attitude change requires the audience to think carefully about the topic. There’s no way to force an audience to think, and there’s no guarantee that any persuasion will work. Still, good speakers give the audience a chance to hear the other side and to come around to a new viewpoint. A good climate speech would also include attention-getters, transitions, and other speaking techniques. 

I’ve tried to show how to present controversial technical content in a way that gives the audience food for thought. 

Hints for presenting statistics in a speech: 

1. Round numbers off. Don’t say, “In Texas, there was an average of 5.8 homicides per 100,000 population.” Try this: “Almost 6 Texas residents out of 100,000 were homicide victims in one year.“ That’s a littler easier to understand.

2. Compare the numbers to something familiar: “Almost 6 Texas residents out of 100,000 were homicide victims in one year, while almost 170 out of 100,000 died of heart disease.” That gives people context. 

3. Or show a pie graph or bar graph.

If the audience needs exact numbers, put them on a PowerPoint slide or handout or post them on your website. When people are listening, be accurate but don’t overwhelm people with intimidating details. I’ll think about pie graphs and might post something about visual aids at some future time.

4. Organize the statistics. Let’s look back at the UN quotations above. Here’s the pretty technical explanation that they wrote. 

“The atmospheric concentrations of the greenhouse gases carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) have all increased due to human activity.”

“In 2011 the concentrations of these greenhouse gases were 391 ppm, 1803 ppm, and 324 ppm and exceeded pre-industrial levels by about 40%, 150%, and 20%, respectively.” 

That’s good, but you need to read it twice to understand it. In a speech, the audience doesn’t get a chance to listen twice. If the UN group needed to give this information in a speech, instead of a technical report, they could say this: 

“The concentration of greenhouse gases in the atmosphere have all increased due to human activity. For example, in 2011, carbon dioxide was measured at almost 400 parts per million. That’s about 40% higher than it was before the industrial age. Similarly, methane is up about 150%, and nitrous oxide is up about 20%.” 

And so forth. Sort the numbers out and be clear. Refer people back to the written report for the exact numbers.


P.S. I've blogged several times about climate change rhetoric, here, here, here, here, here, here, here, and here. Click on the right for a link to Mike Lee's awful climate change speech. 

You Might Persuade Climate Change Skeptics by Giving Them Information

Climate Change and the Amazon Drought

The big problem with most climate change speeches is that the speakers tell the audience that there is a lot of evidence about climate change, but they don’t explain what the evidence is. I showed in my previous post that you can’t persuade climate change skeptics by insulting them and calling them names. You also can’t persuade climate change skeptics just by promising that the scientists agree. That asks them to change their minds on faith, and skeptics are not going to change their minds on faith. They need evidence. That doesn’t mean that evidence will always persuade them; it won’t. But evidence is all we have.

Persuasion Theory

Let’s go over a few basic points of persuasion theory.  A well-established persuasion theory is the Elaboration Likelihood Model, which I have written about a few times. This theory, developed by psychologists Richard E. Petty and John Cacioppo, says that there are two paths by which listeners process persuasive messages. People follow the central path when they think about a message carefully. This occurs when people are motivated to analyze a persuasive message and feel that they have the skill and knowledge to do so. The peripheral path does not involve careful thinking. Instead, the listener relies on peripheral cues, such as whether the listener likes the speaker, finds the speaker attractive, or already has a positive attitude toward the message. The number (as opposed to the quality) of messages gives listeners a peripheral cue.

When people change their attitudes over the central route, the attitude change is likely to be long-lasting and to influence their behavior. For example, it might influence their long-term voting. But attitude change that occurs over the peripheral route is likely to be temporary and easily changed. Furthermore, attitude change over the peripheral route is unlikely to change people’s long-term behavior. Much advertising, including most political advertising, aims at the peripheral route. That, for example, is why many political messages are ridiculously short and convey little actual information. Voters who process information on a given topic by the central route will ignore such short, simple messages.

Speakers cannot control whether the audience will process a message by the central or peripheral route. They can, however, offer the audience opportunities to process information. When a speaker says, “scientists agree about climate change,” the speaker is appealing purely to the peripheral route. That almost all scientists do, in fact, agree about climate change is a peripheral cue. Climate change skeptics, however, are exposed to many other peripheral cues.  For example, they hear Fox News hosts and talk radio personalities call climate change a hoax. When speakers give the audience too little information, they offer the audience little chance to process a message by the central route. Of course, a highly motivated audience member can find the research on Google Scholar. But how many people will do so? Climate change speakers make a mistake when they do not invite central route processing. Here are the reasons why and what to do about them:

First, the evidence for climate change is complex. A superficial speech cannot address complexities.

Second, audience members might not feel that they have the knowledge or ability to analyze the scientific information for themselves. People use the central route only when they feel motivated and capable. That is why it becomes a speaker’s job to present information in a way that is accessible and persuasive. That requires a speaker to do research (and I’ve often commented that speakers need research) and to present that research to the audience in a way that is clear and well-organized. That requires a speaker to make a lot of effort, but the effort might pay off in a higher likelihood that the audience will choose to process the information critically.

Third, the speaker needs to give the audience a reason to think carefully about climate change. The central route requires effort! That is where Greta Thunberg has been doing a great job. She is enthusiastic and knows how to get the audience’s attention. But what she has not done, however, is to help people understand the information. That’s probably too much to expect from any 16-year-old speaker, no matter how smart she is, so it’s time for other speakers to pick up the load and take the next step.

Fourth, it is necessary to anticipate the most common objections that climate change skeptics present. Skeptics will say that scientists once complained about global cooling, which is partially true. They will point out that there are natural causes of climate change. This is also true, although a bit beside the point. Some people will flat-out deny that the climate is changing at all, since day-to day weather changes much more than the two degrees of warming that we’ve seen so far from climate change. Speakers should not expect conservative objectors to give them a reasonable chance to engage in back-and-forth dialogue. That experience, which high school and college debate teams take for granted, rarely occurs in the real world. Instead, speakers need to anticipate and preempt the major objections, and to refute those objections with care. Speakers should assume that they only get one shot to make their case. (That doesn't mean that one speech is enough, but that's a topic for another day.) Again, asking the audience to take something on faith invites them to process the message by the peripheral route.

All effective persuasion comes down to giving people information. The better job a speaker does of presenting information, the more likely it is that audiences will respond. We ask a lot of people when we expect them to cut back how much they use the fossil-fuel energy sources that have made the industrial nations so prosperous. It is wrong to think that changing people’s minds will ever be an easy job. Any time we think about persuasion, we need to think about the audience.

So, that’s what persuasion research tells us. In my next post, I’ll show how these persuasion principles might work in a practical way. 

P.S. Many good sources explain the Elaboration Likelihood Model. Here’s a simple, accurate explanation by an Oregon State University professor. Any current persuasion textbook will also discuss this model. Ambitious (and wealthy) readers can buy an e-book version of Petty and Cacioppo’s book here.

Image from NASA.