Climate Science and Science Literacy: The Strange Divergence

When it comes to climate, "just the facts, ma'am" doesn't seem to cut it for some.

One big puzzle for climate scientists: despite ever-growing scientific evidence that the climate is changing and that the change is largely due to human activities (see here and here), a significant fraction of the American public remains unconvinced.

What's to be done? Well, if you're a scientist, the answer is obvious -- provide the unconvinced with more evidence, more data, and surely they will come around. Problem is, scientists continue to do just that and continue to make little or no progress or, worse, lose ground. (See here and here.)

Two studies -- one by Lawrence Hamilton of the University of New Hampshire published last week in the journal Weather, Climate and Society and the other by Dan Kahan of Yale University and colleagues published in the journal Nature Climate Change in May -- provide an explanation: for some, it appears, personal beliefs and cultural associations trump scientific facts.

A Tale About Arctic Sea Ice

Hamilton's paper reported on national and New Hampshire-based surveys that queried individuals' general demographics and political beliefs and their opinions about specific issues related to climate change.

The critical aspect of the climate-change questions is that they avoided issues that would have required a value judgment and focused on factual information -- in the author's words "uncontroversial observations."

One of the questions related to the trend in late-summer Arctic ice: specifically, whether the ice cover over the Arctic Ocean "over the past few years" covers less, about the same, or more than it did 30 years.

The answer to that question is straightforward and derived from empirical facts: since satellite monitoring of sea ice began in the 1970s, the late-summer sea ice cover has declined dramatically, finishing this past season at an all time low. (See here and here.)

Monthly September ice extent for 1979-2012 shows a decline of 13 percent per decade. (Credit: National Snow and Ice Data Center)

The responses to the question are sort of fascinating. Most people answered correctly.

But the significant percentages who answered incorrectly (19 percent nationally, 17 percent in the Granite State) also tended to either reject the whole notion that the climate is changing at all, or accept it is changing but reject that humans have anything to do with it. Hamilton posits two explanations for those who rejected both human-caused climate change and the observational facts concerning declining sea ice:

  • Science illiteracy: People who believe climate change is not occurring are poorly informed (scientifically illiterate) and hence do not know that Arctic sea ice has declined.
  • Assimilation bias: People who believe climate change is not occurring are disinclined to assimilate facts that run contrary to their belief, such as the fact that Arctic sea ice is declining.

The science illiteracy explanation fits nicely into the narrative we scientists are most comfortable with: people lack adequate information and can be brought around by simply providing the facts such as the record of sea ice coverage over the past 30 years.

The assimilation bias explanation is a good deal more perplexing for scientists since it suggests that providing more information and evidence will make little or no difference (see an earlier post on this subject).

Illiteracy or Bias

Which is it? Both Hamilton's work and that of Kahan suggest it is the latter. That our cultural and political beliefs and not a lack of information, per se, lead some to reject the facts of climate change.

For example, it is well known that the climate-change fault line runs along the political-party divide with Democrats much more likely to accept and Republicans more likely to reject climate science.

But Hamilton and Kahan both found that there is also an educational divide, actually a double divide. Hamilton found that the probability of a response that human activities are driving climate change increases with Democrats' educational background: There is a more than 50 percent probability that a high-school-educated (or less) Democrat will respond positively to the climate change/human activities question, and that probability increases to more than 70 percent for a college-educated Democrat and above 80 percent for a Dem with post-graduate education.

For Republicans, in contrast, increasing education makes virtually no difference in their acceptance of anthropogenic climate change. Roughly 70 percent of Republicans with a high school education (or less) reject climate science, and about the same percentage holds for Republicans with a post-graduate education.

(The whole education piece makes me think back to 2006 when Supreme Court Justice Antonin Scalia responded to being corrected for his incorrect use of the word stratosphere with: "Troposphere, whatever. I told you before I'm not a scientist. … (laughter) That's why I don't want to have to deal with global warming, to tell you the truth.")

The Culture Angle

Kahan et al’s results (based on a survey of "climate-change risk perceptions" among 1,540 U.S. residents) are similar in many respects to Hamilton’s. These authors also found a party-affiliation divide among Democrats and Republicans. They also found a strange relationship between science literacy and, in this case, perceived risks related to climate change.

  • As science literacy increased among Democrats, the perception of climate-change risk also increased, but
  • As science literacy increased among Republicans, the perception of climate-change risk actually decreased.

In explaining these trends, Kahan et al. acknowledge the party-affiliation divide but argue that political affiliation per se is not the determining factor -- instead it’s peer relationships and community beliefs. Earlier work by Kahan et al. found that Americans’ worldviews tend to fall into one of two generic groups -- individual (or hierarchical) types who favor personal initiative, and communitarian (or egalitarian) types who favor goals that limit disparities -- and where one falls in this worldview split plays a role in how we hear information on climate, with hierarchical individuals being less likely to accept climate science.

"Given how much the ordinary individual depends on peers for support -- material and emotional -- and how little impact his beliefs have on the physical environment, he would probably be best off if he formed risk perceptions that minimized any danger of estrangement from his community... It is effectively costless for any individual to form a perception of climate-change risk that is wrong but culturally congenial." (Kahan et al., "The Polarizing Impact of Science Literacy and Numeracy on Perceived Climate Change Risks,” Nature Climate Change, published online 27 May 2012.)

The implication: Further "education" on climate science alone is unlikely to make inroads with people who have already decided that climate change is not real or not human-induced. Kahan et al. argue that the way to make headway against this cultural resistance to climate-change facts is to find climate-change messengers who would be viewed as being of or from the culture that people who deny climate change identify with.

Is That True? And If So, What Can Be Done?

The results of Hamilton and Kahan present a difficult and ironic challenge to the scientific community. Our worldview posits that what Hamilton calls "an information-to-conclusions ordering" is the process that people use to understand the natural world. Now along come the results of Hamilton and Kahan et al., which run contrary to that worldview. If they are right and we want to make progress on communicating climate change, we are going to have to succeed at doing what these authors found climate deniers could not -- overcome assimilation bias and surrender tightly held cultural norms and adjust our message accordingly. If we don't, we may fail by falling prey to the same forces that cause so many to reject empirical facts about the climate.

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