Here’s what happens when you tell people the scientific consensus on climate change

You can turn red states green

Earth’s average global temperature from 2013 to 2017 compared to a baseline average from 1951 to 1980. Yellows, oranges, and reds show regions warmer than the baseline. Credit: NASA.
Earth’s average global temperature from 2013 to 2017 compared to a baseline average from 1951 to 1980. Yellows, oranges, and reds show regions warmer than the baseline. Credit: NASA.

The overwhelming majority of climate scientists  — 97 percent   — understand that humans are the primary cause of climate change.

Yet, as a new peer-reviewed study in journal Nature Climate Change points out, “only 11 percent of the US public correctly estimate the scientific consensus on climate change as higher than 90 percent.”

Scientific consensus results on the question of human-caused global warming. CREDIT: John Cook.
Scientific consensus results on the question of human-caused global warming. CREDIT: John Cook.

So what happens when you inform people about the actual consensus on climate science?

Researchers in the Nature study did a survey experiment with 6,300 Americans and found “Exposing the survey respondents to the message about the scientific consensus increases their perception of the scientific norm by 16.2 percentage points on a 100-point scale” (when asked the question later).

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In other words, a person’s understanding about what scientists know about climate change goes up after they are told just how many scientists agree it’s human caused.

But the researchers were surprised to find that the change in perception varied  significantly by state, which is not an effect most studies examine. Indeed, the changes were generally “highest in more conservative parts of the country, leading to national convergence in perceptions of the climate science consensus across diverse political geographies” (see chart)

Difference by state in change in belief in the scientific consensus between the group exposed to the consensus message  and a control group, who were not. CREDIT:  Nature.
Difference by state in change in belief in the scientific consensus between the group exposed to the consensus message and a control group, who were not. CREDIT: Nature.

In short, the message about the scientific consensus works in all states. But it has the biggest impact in the states that had the most misinformation about the overwhelming level of consensus (and the smallest impact in the most liberal states).

Back in March, a major Gallup survey on global warming found that only 42 percent of Republicans “say most scientists believe global warming is occurring,” whereas 86 percent of Democrats understand that.

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So, messaging on the scientific consensus can reduce partisan polarization on the climate issue. Also, social science research has shown that when people are informed about the reality of the overwhelming consensus they become more inclined to want to take action.

A 2016 study by the authors of seven different consensus studies found that while the consensus varies slightly depending on which experts are surveyed, “most of our studies [found] 97 percent consensus among publishing climate scientists,” as lead author John Cook of Skeptical Science explained.

Also, “The greater the climate expertise among those surveyed, the higher the consensus on human-caused global warming.”

There are a variety of ways to communicate the consensus message. The simplest version: 97 percent of climate scientists understand that humans are causing climate change.

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A more specific version: The overwhelming majority of climate scientists — 97 percent — understand that humans are the primary cause of global warming since 1950.

Finally, a good analogy to use would be: We are as certain that humans are responsible for recent climate change as we are that cigarettes are dangerous to your health.

But, however you say it, the important point is to say it to every possible audience.