Last week the Pew Center released a new poll regarding the “Changing Opinions About Global Warming.” The polls are certainly telling, if not alarming: in April 2008 71% of Americans believed there was solid evidence that the earth was warming. That’s down to 57% this month.
Perhaps more importantly, the percentage of those people who believe global warming is due to human activities is down from 45% in 2008 to 36% now. The only demographic in which belief in global warming rose were young democrats, ages 18-29, by 5%.
The Pew Report follows on a wave of debate sparked by Paul Hudson’s blog-post-turned-article on the BBC’s News website, “What Happened to Global Warming?“ Global warming skeptics have found encouragement from Hudson’s article and the Pew Report, and have lashed out against Brian Williams’ suggestion on NBC Nightly News that people were less concerned with environment in a down economy, sparking a wave of protest around the blogosphere. The New York Time’s Weekend Opinionator tracked those opinions last weekend. But researchers at the Center for Research on Environmental Decisions have noted that humans have a “finite pool of worry:” concern about the environment is likely to wane when one loses their job or is facing other stresses.
Looking back at the history of the phrase “Global Warming,” we note that it was actually coined by a Lamont-based scientist, Wally Broecker, in 1975. (Links to PDF). His point was not to start a movement on curtailing greenhouse gases, but rather to superimpose global trends in anthropogenic-related temperature increases over natural climate cycles. These include orbital shifts, changes in the solar cycle, and decadal and seasonal to interannual variability such as the Pacific Decadal Oscillation (PDO) or the El Nino Southern Oscillation (ENSO). Hudson notes that the PDO can lead to cooling periods of about 30 years that have the net effect of “canceling” rising temperature trends and may be responsible for the current stable global temperatures.
The climate that we observe is a result of the interaction of all these forcing mechanisms. While the balance of current forcing is “masking” the effect of greenhouse gases, the forcing can and likely will shift to reinforce anthropogenic warming. As Wally Broecker has indicated, climate is complex “beast” and human emissions of greenhouse gases are like poking the climate with a stick.
Something especially important to remember that often gets lost in the debate: local weather is not the same as climate. Global warming means an overall increase in the global average temperatures (right now we’re on track for a 1.5 degrees C increase), but the effects of global warming don’t mean that local weather conditions will necessarily be warmer everywhere. What it does mean is that global weather patterns will shift, redistributing clouds, precipitation, ocean currents such that some places will experience warming, and some places cooling. And natural variability, be it from solar forcing, the PDO or ENSO, will continue to influence climate and weather patterns.
So what does this have to do with public perceptions of climate change? If it’s cold outside and raining, one is unlikely to feel that global warming is as real as if one is in the midst of a record-breaking heat wave. Although local weather is not climate, it is how we experience climate. It is hard to forget that what we see and feel today is just one point on the globe and one point in time. In a moment of economic uncertainty, it is hard to worry about something that is not directly observable to the guy on the street, especially something that may not have visible impacts for several decades.
But perceptions are not a measure of whether a scientific idea is correct or not — perceptions reflect the conditions of the moment and the understanding of the moment. We need to remember that moments are just that, and climate change will still continue on long, long past this one.