"Americans and Climate Change: Closing the Gap Between Science and Action" (PDF) is a report synthesizing the insights of 110 leading thinkers on how to educate and motivate the American public on the subject of global warming. Background on the report here. I’ll be posting a series of excerpts (citations have been removed; see original report). If you’d like to be involved in implementing the report’s recommendations, or learn more, visit the Yale Project on Climate Change website.

OK, now we’re getting past the introductory stuff and into the meat of the report. The first chapter is on the challenges science and scientists face in communicating to the public about global warming. It’s incredibly revealing, touching on several things we’ve discussed here.

It’s a long chapter, so I’ve split it into three parts. The first is below the fold.


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We are only aware of climate change as a human-induced phenomenon because of science. Given this scientific "origin," the default tendency of those who seek to propagate the issue throughout society is to preserve its scientific trappings: by retaining scientific terminology, relying on scientists as lead messengers, and adhering to norms of scientific conservatism. Such practices can cause profound disconnects in how society interprets and acts on the climate change issue, and they deserve our remedial attention.

Climate change is a quintessentially scientific issue in that, without the scientific method, we would not be aware of it. We would not be talking about human causality. We would not be assembling the disparate data points from around the globe and seeing their total significance. Yet when an issue is scientifically defined, it is not always clear how long it should remain so as it is propagated throughout society.

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Scientific Word Choice and Metrics

We have not yet found the right words to communicate about climate change, arguably including the name of the phenomenon itself. Is it appropriate to factor marketability and motivational power into the very naming of a scientific phenomenon, or is that the sacrosanct province of the scientists? Scientists appear to prefer the term climate change because it is more encompassing — allowing for non-temperature effects such as precipitation, chemical alteration of the oceans, as well as a patchwork of warming and cooling regions.

Polls of the public, meanwhile, indicate that the phrase "global warming" is more attention-getting and unsettling to people than "climate change," even though "warming" on its own has a pleasant, welcoming ring. Alternative terms have been proposed, including "climate disruption," "runaway warming," or "catastrophic warming."

Few Americans can distinguish the meanings of weather and climate. Since they routinely experience rapid weather changes, why should a change in climate be any more concerning? Longstanding models of balance and equilibrium in ecosystems have largely been superceded by new ones emphasizing constant change, chaos, multiple equilibria and amplifications of small causes into large effects. Given all this, and the historical evidence of major climate changes prior to the onset of human influences (from the Cretaceous Thermal Maximum to the Permo Carboniferous Glaciation), it can sound like a fool’s errand to stop climate change, or any other change for that matter.

Nonetheless, those seeking to advance societal action on the issue appear to have resigned themselves to perpetuating the scientifically preferred term "climate change," but should they? It is arguably not too late to revisit the naming conundrum if we place sufficient value on the specific goal of translating science to action.

Apart from its naming, the issue has been loaded up with an impenetrable construct of jargon — ranging from the scientists’ "positive feedback loops" or "positive radiative forcing" ("positive" in these cases actually refers to something bad) to the policy-makers’ tradable emissions permits denominated in "tons" of carbon dioxide-equivalent (to the average American, "tons" presumably connote elephants more than invisible air molecules). Scientists say "anthropogenic" when "man- made" would be more widely understood.

The impact of scientific conservatism on word choice can be seen in the varying interpretations of the Intergovernmental Panel on Climate Change’s (IPCC) Second Assessment Report in 1995. The most widely reported phrase from that report was that "the balance of evidence suggests a discernible human influence on global climate." To those predisposed to concern about the issue, this statement equated to a smoking gun. After all, thousands of scientists laboring in distinct countries and sub-disciplines had come to a consensus that the signal of human impact could now be distinguished from the noise of natural variability.

Yet in common parlance, discernible implies tiny, or at least barely detectable. Can the layperson be expected to hear this smallish word and immediately thrust the issue to the top of his or her agenda of concerns? Incidentally, the IPCC’s Third Assessment Report in 2001 strengthened the language about the human role, saying: "There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities." But the point stands: word choices at any given moment in the unfolding communication of an issue can be interpreted differently based on the prior dispositions of the person hearing the message.

A pervasive, and probably underestimated, problem in scientific-public discourse is the nearly universal use of the scientifically preferred Celsius measure for temperature in communicating about climate change, even though Fahrenheit remains the ubiquitous measure in the U.S. and the only one to which average Americans can relate. This default usage of Centigrade (the Celsius measure) is problematic also because the numbers are smaller and the magnitude of current or projected warming is therefore perceptually diminished. So the IPCC’s projected range of a 1.4 — 5.8° Centigrade rise in temperature by 2100 sounds notably smaller than its 2.5 — 10.4° Fahrenheit equivalent.

Choose Your Consequence

For those aiming to raise public awareness of the projected consequences of climate change, a laundry list is available: sea-level rise, extreme weather events, droughts and water shortages, agricultural and food risks, infectious disease, ecosystem loss, species extinction, and others.

The Biblical quality of these consequences — floods, droughts, plagues — has often been assumed to be an advantage in getting people’s attention, even though the associations with divine wrath may also promote a sense of human futility.

An intuitive overview suggests, moreover, that many of the climate change risks may not be as viscerally unsettling to people as one might think. Sea-level rise may be perceived as inherently geological and long- term, even if accelerations lie ahead from unexpectedly rapid ice sheet melting (new satellite observations reported in the journal Science in February 2006 show that Greenland’s glaciers are sliding toward the sea almost twice as fast as previously thought). The spread of climate- sensitive diseases to new latitudes and elevations sounds troubling, but disease risk is a probabilistic phenomenon and many people appear to like their chances in such situations. Food scarcity from disrupted agriculture and threats to drinking water may cut closest to home, but at least in the industrial world, the image of plentiful grocery stores is so deeply imprinted that it may be difficult to shake it loose even if a particular projection warrants it.

The fact is that there is surprisingly little hard evidence about which of the many climate change related risks are of greatest concern to the American population. The risk perception and communications fields have largely focused elsewhere (e.g., seat belt usage, drunk driving, STDs, cancer screening), typically on issues of personal behavior rather than daunting collective action problems like climate change. And the major survey organizations rarely probe these depths, instead going only so far as asking whether Americans think global warming is a serious or very serious problem as a whole.

Even if we had better data, one may ask whether it is scientifically legitimate to select some consequences above others for motivational purposes, when the science encompasses all of them. If an important goal is to translate science to action, however, such choices may simply need to be made. Communications can be constructed that remain faithful to the natural sciences, while doing much more to reflect our advancing understanding of how human beings assess risks.