In the early days of current concern about the impact of rising concentrations of carbon dioxide and other greenhouse gases on the global climate the phenomenon was generally described as global warming. Then environmentalists and some scientists found that those who denied the impact of rising concentrations of greenhouse gases on the climate were making progress with their ideas by pointing out that some key inhabited regions periodically experience cold spells and may in fact experience periods of more extreme cold more frequently in the future. Advocates lobbied successfully for changing the popularly used term to climate change.

Now a report from researchers with the Yale Project on Climate Change Communication and the George Mason University Center for Climate Change Communication suggests that the American public understands global warming much better than they understand climate change. Maybe the switch is terminology was not such a good idea after all.

Among the findings of the report:

• A nationally representative survey in January 2014 found that while Americans are equally familiar with the two terms, they are 4 times more likely to say they hear the term global warming in public discourse than climate change. Likewise, Americans are 2 times more likely to say they personally use the term global warming than climate change in their own conversations.
• A separate nationally representative survey (Survey Study 2) in November-December 2013 found
• that almost without exception, global warming is more engaging than climate change. Compared to climate
• change, the term global warming generates:
  • Stronger ratings of negative affect (i.e., bad feelings)
  • Overall, global warming generates significantly more top of mind associations to Icemelt (e.g., “melting glaciers”), Alarm (e.g., “world catastrophe”), Flood (e.g., “coastal flooding”), and Ozone (e.g., “the ozone hole”) categories. Climate change generates significantly more associations to Weather (e.g., “storms”) and Global Warming (e.g.,“global warming”) categories.
  • Within the Weather category, global warming generates a higher percentage of associations to “extreme weather” than does climate change, which generates more associations to general weather patterns.
  • Greater certainty that the phenomenon is happening
  • Greater understanding that human activities are the primary cause among political Independents.
  • Greater understanding of the scientific consensus among Independents and liberals.
  • More intense worry about the issue, especially among men, Generation Y, Generation X, Democrats, liberals and moderates.
  • A greater sense of personal threat.
  • A greater sense of threat to one’s own family.
  • A greater sense of threat to future generations among Independents and Generation Y.
  • A greater sense that people in the U.S. are being harmed right now,
  • Higher issue priority ratings for action by the president and Congress.
  • Greater support for a large or small-scale effort by the U.S. (although climate change generates more support for a medium-scale effort, especially among Republicans).
  • Greater willingness to join a campaign to convince elected officials to take action.
• Use of the term climate change appears to actually reduce issue engagement by Democrats, Independents, liberals, and moderates, as well as a variety of subgroups within American society.
• Overall, Americans are slightly more worried about global warming (52% are very or somewhat worried about it) than they are about climate change (48%). Americans are +6 points more likely to be “very worried” about global warming (15%) than climate change (9%), which is a statistically significant difference.

The authors note that connotative meanings are dynamic and change, sometimes rapidly. It is possible that with repeated use, climate change will come to acquire similar connotative meanings as global warming, that the two will eventually become synonymous for most people, or that climate change will supplant global warming as the dominant term in public discourse. In the meantime, however, the results of these studies strongly suggest that the two terms continue to mean different things to many Americans.

The report contains much more data on public opinion analysed by use of the terms global warming and climate change, also by political inclination. We have not summarized that data here as it is based on the US political system and, like the rest of the report, may have little or no relevance to Canada. However, with no similar data available in Canada, we encourage readers to look at the US data and come to their own conclusions about its relevance to Canada.

Many people understand global warming and climate change as virtually the same thing but technically they are not identical. Put simply, global warming is a result of increasing greenhouse gases in the atmosphere and, after human releases of such gases. is the factor which causes the problem. Climate change, the increasing frequency and severity of disturbances in the already disturbed atmosphere, is the result of global warming. However, GallonDaily’s opinion is that information sources should use whichever term is best understood by users of the information.

The 31 page report What’s In A Name? Global Warming vs. Climate Change is available at http://environment.yale.edu/climate-communication/article/global-warming-vs-climate-change/