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What is a Consensus? · The Climate Translation

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We're often told that 97-98% of climate scientists agree that human activity is warming
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the planet.
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But then, you turn on the news and see a prominent politician say that statistic is based on
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one discredited study.
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So who's right?
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The vast majority of experts agree, why does it feel like a 50-50 debate?
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Welcome to the podcast.
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I'm Dr. Mac, and this is The Climate Translation.
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Before we talk about the numbers, we need to talk about the word itself, consensus.
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In science, consensus isn't just a group of people agreeing because they like each other.
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What happens when the vast majority of specialists in a field agree on a basic principle because
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the evidence has become so overwhelming that it's no longer worth arguing about.
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We live our lives by scientific consensus every day, often without realizing it.
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It's agreed that the Earth orbits the Sun.
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We accept that tadpoles grow into adult frogs.
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But all geologists agree that plate tectonics is a reality, and you'd be hard pressed to
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find a doctor who still thinks that smoking is harmless.
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Now here's the catch.
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None of those examples, not even the Earth orbiting the Sun, have 100% agreement.
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You can always find an outlier.
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There's always someone who's willing to take a contrarian stance.
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Sometimes it's for personal belief, and sometimes it's for more complicated reasons.
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Humans are naturally skeptical, and in science, that's actually how progress works.
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We argue.
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We test.
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We peer review a hypothesis until it survives enough interrogation to graduate into a theory.
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But when we reach a point where the vast majority of experts stop arguing about the basics,
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we call that a consensus.
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It's the point at which the data has spoken loudly enough that we can move from asking,
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is this happening?
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Well, what do we do about it?
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That brings us to the clickbait sound bite that came out of Washington a few years back,
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the one study claim.
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It's often reported that somewhere between 97 to 98% of climate scientists agree that humans
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are the main driver on the rapid climate shifts we're seeing on the planet.
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Yet politicians continue to dispute this.
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One stated that the idea that there is consensus is based on just one discredited study, and
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that statement was covered in all the major news outlets.
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As an educator, this is a light bulb moment waiting to happen.
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If the consensus were a house of cards resting on a single, academic paper, well, I'd be skeptical too.
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But the truth is, the house is built on a foundation of many major independent studies.
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The first major effort to measure this consensus didn't even look at scientists' opinions,
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but at their actual work.
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In 2004, a scientist named Naomi Oriskas surveyed 928 scientific papers on global climate
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change, and found that not a single paper rejected the consensus position that global warming
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is man-made.
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In 2009, a study by Doran and Zimmerman asked 3,146 Earth-scientists a simple question.
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Do you think human activity is a significant contributing factor in changing the mean
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global temperature?
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While 82 percent of all Earth scientists said yes, that number jumped to 98 percent
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among actively publishing climatologists.
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In contrast, only 77 percent of non-climatologists who weren't publishing research agreed.
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In 2013, Dr. John Cook and his colleagues at the University of Melbourne analyzed over
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12,000 peer-reviewed scientific papers and found that 97.1 percent of those taking
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a position agreed that humans are causing global warming.
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To be even more transparent, they asked 1,200 of the original authors to rate their own
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papers, and those scientists reported a 97.2 percent consensus.
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And in 2021, and a massive study of 88,125 climate-related papers published since 2012,
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researchers found that the consensus now exceeds 99 percent in peer-reviewed literature
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among the subset of confirmed climate experts with the highest level of expertise, meaning
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they have individually published more than 20 papers, the agreement reached 100 percent.
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So when you hear there's no consensus or that it's based on one discredited study,
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remember that those numbers aren't just a snapshot.
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Their result of thousands of experts reviewing tens of thousands of papers over several decades.
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The consensus gap isn't a lack of scientific agreement, it's a gap in how that agreement
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is communicated to the public.
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In my classes I often tell my students, science is a team sport, but the media loves a solo
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superstar, and that's where this consensus gap gets dangerous.
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That's what happens when one of those outliers becomes a celebrity that everyone latches
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onto to justify their viewpoint.
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I experienced this firsthand many years ago.
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I was working on a research grant to create a series of events at a major aquarium on
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the Gulf Coast.
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The goal was to have an open discussion with the public about the intersections of climate,
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weather, and human health.
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But before I took over the program, the guest scientist they brought in was just such
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a celebrity skeptic.
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Now the expert they tapped was a credential scientist.
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At the time he was a professor and the state climatologist for one of the Gulf Coast
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states, but he was a pioneer of what I call alternative science.
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Back in 1989 he and his colleagues used satellite data to claim the earth wasn't warming
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at all.
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Even though later reassessments by the Bush administration and other scientists found
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significant errors in his work, the damage was done.
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He had become a celebrity for the skeptical camp.
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He is who they turned to when they wanted someone to back up their viewpoints.
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Working with him was incredibly difficult.
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We disagreed on almost everything.
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While the vast majority of his scientific peers were looking at a mountain of evidence,
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he was teaching that human-adduced climate change was a hoax.
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And because he had a doctor in front of his name and a prestigious position at a university,
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he provided what political leaders call scientific cover.
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This is the heart of the problem.
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When you have one scientist who tells people what they want to hear, that they don't
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have to change their lifestyle or worry about the future, that one voice can muffle the
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98% who are telling the difficult truth.
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In the 90s and 2000s, this wasn't just a coincidence.
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There was a deliberate battle plan created by fossil fuel interest and free market think tanks
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to recruit these new faces to add their voices to the debate.
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They knew if they could manufacture a celebrity skeptic, they could create the illusion that
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the science was up for debate, and that allowed them to avoid costly changes to their business
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plans due to national and state laws and regulations.
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That scientist was charismatic too.
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People bought into his message because he was articulate and likable.
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It didn't matter, he was an outlier, and that he had been caught manipulating data.
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As an educator, seeing that muddled message at the aquarium was heartbreaking.
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People weren't leaving with a better understanding of the environment, they were just leaving
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confused, and in the world of climate change, confusion is as good as NO for those who want
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to prevent action.
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So how do we make sense of a world where 98% of experts are in agreement, but the outliers
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are the most vocal and charismatic speakers in the room?
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How do you cut through the noise when the person telling us it's all fine sounds much
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more certain than the scientist is talking about ranges of probability?
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We have to recognize that this is the classic consensus gap, and science, a consensus is
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reached by people who have spent years learning how to work with complex data and identify
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what constitutes actual evidence.
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Look consensus on the other hand, usually only happens when something is blindly obvious,
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like the existence of owls because we can see and hear them.
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Climate change is more complex, and that complexity makes it a target for misinformers.
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When a celebrity skeptic stands up with credentials and a smile, they're often providing what people
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are looking for, a reason to ignore the problem.
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It's a powerful psychological shield, but it's one that has been carefully manufactured
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by interest groups to delay action.
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So given this, how do you take this information and actually use it in a real conversation
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with a friend, a family member, a colleague, who is latched on to these vocal outliers?
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Well first, acknowledge the trust factor.
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Start attacking them or their intelligence.
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Start by acknowledging that we all defer to experts because none of us has the time to
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learn everything.
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Say, I understand that you'd listen to that scientist.
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They sound convincing.
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It's natural to trust an expert.
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You can use the doctor comparison.
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This is the most effective translation for the 98% consensus.
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Ask them if you were seriously ill, and 98 doctors told you that you needed a specific
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surgery, but two told you you'd be fine.
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Would you bet your life on the two?
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Even if one of those two was a celebrity doctor featured on podcast on the television.
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Highlight the expert T's variable.
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Explain that the debate isn't scientist versus scientist.
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It's experts versus non-experts.
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Imagine if you noticed a large crack in the foundation of your house.
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You're worried the whole building might be shifting, so you ask for advice.
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You have ten neighbors.
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They're all handy with tools.
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They've built decks and fixed sinks.
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Eight of them say, yeah, that looks like a structural problem.
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But two of them say, eh, don't worry about it.
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Houses just settle.
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That's an 80% consensus, but you're still confused because two neighbors seem really
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confident.
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So you call ten licensed general contractors.
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These are people who build houses for a living.
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This time, nine of them tell you it's a serious foundation issue.
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Now you're at 90%.
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The signal's getting clear.
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Finally, you decide to bring in ten structural engineers who specialize only in soil science
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and foundation failure.
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They spend every single day studying exactly why dirt shifts under concrete.
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All ten of them look at your data and tell you the same thing.
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Your foundation's failing and you need to get it fixed now.
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That is 100% consensus.
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This is exactly what we see in climate science.
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If you ask scientists in general, you'll get a high number.
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But as the level of active research and specialization in climate science increases, so does
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the agreement that humans are the primary driver.
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Only expose the false balance.
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Help them see that the media often creates an unbalanced perception of reality by giving
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two to three percent of skeptics over half the air time.
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When we try to be balanced, we often actually end up being inaccurate.
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The goal isn't to win the argument.
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It's to help your friend or family member realize that they might be looking at a very
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small slice of the pie and mistaking it for the whole meal.
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When we close this consensus gap, we move one step closer to actually understanding and
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maybe even fixing the world we live in.
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Thank you for joining me for this episode of the Climate Translation.
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My hope is the next time you hear someone say, there's no consensus, you don't feel overwhelmed.
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Instead I hope you feel that you have something in your toolkit to help bridge that gap.
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If you found today's analogy helpful, I'd love for you to share this episode with someone.
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Maybe that one friend who's always sending you links to alternative science.
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Let's start building those bridges one dinner table conversation at a time.
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I'm Dr. Mac.
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If you have a question about the climate you've been too afraid to ask or if you have
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a differing opinion, I want to hear from you.
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I can use your viewpoint and a future episode.
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You can reach me at the climate translation at gmail.com.
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I'll see you next time.