Tuesday, May 07, 2013

Talking about climate change in a hot and cold world

There's been a small burst of skepticism about the science of climate change in the media in the past few months, as if arguments usually confined to dark corners of the internet oozed out into the hallway. This was encapsulated in the well-researched but misleading article in the Economist that suggested the climate may be much less sensitive to greenhouse gases than previously thought. This emergence of skeptical arguments in the public realm is in sharp contrast to last fall, when concern about climate change was supposedly increasing, both among the media, and in opinion polls.

What has changed?

For one, the weather.

Last winter, central and eastern North America bathed in record heat, including cases where March temperature records were broken by 8 degrees Celsius. That was followed by the warmest summer in U.S. history [and, in the fall, by the sea-level rise assisted storm surge from Hurricane Sandy].

Consider this quote about the U.S.:

By July... there were cover stories in news weeklies, lead articles on broadcast news programs, and hundreds of newspaper and magazine writeups appearing on the presumed connection between the heat wave and the greenhouse effect. With a few exceptions, there was very little scientific content in most of the stories. Instead, dramatic visuals of damaged crops, dried up rivers, sweltering cities, record hurricane pressures, or burning forests dominated the coverage...  

Unlike last year, this winter and early spring was cold and snowy across central and eastern North America as well as much of Europe, regions that happen to be home to much of the world's English-language prestige press, not to mention most of the loud voices on climate change.

A recent paper by my former student Jeremy McDaniels and I found that American attitudes about climate change tend to follow the weather. Analysing polling data and newspaper op-ed content from 1990 through 2010, we found that after periods of unusual warmth, people tend to be more convinced and more concerned about climate change. Conversely, after unusually cold periods, people's views tend to go in the opposite direction.

Let's be clear: The relationship detected in our paper does not necessarily mean that people confuse weather and climate, concluding after a cold winter that, say, global warming has stopped. The cold period may directly or indirectly lead people to revisit a meme about slowing of global warming. And it's impossible to say with any level of certainty whether this dynamic has played an important role, or any role, over the past few months. We're talking in loose terms about a single data point, and a fuzzy one at that.

Plus, I have misled you about one thing.

That quote? It was not actually from last year. It is from a 1989 Climatic Change editorial by Steve Schneider about the summer of 1988. It continues:

Better stories pointed out that there was some debate as to whether anyone could ascribe the weather events of one year to a global trend. After all, the drought in May and June was a result of an out-of-position jet stream, which diverted storms up into Canada rather than across the mid-United States... But most coverage, especially on television, had little discussion that reflected the consensus of views on what is well accepted and what is deemed speculative by most researchers. Mostly, the association of local extreme heat and drought with global warming took on a growing credibility simply from its repeated assertion. 

Sound familiar? Schneider was worried about how scientists should talk about human-caused climate change in light of the natural variability in the climate. If we talk only about the "signal" and ignore the "noise", we are not being completely forthright, and we risk confusion down the road.

Therefore, my excitement at the long-overdue public attention the greenhouse affect was finally receiving was tempered substantially by a fear that should next summer be anomalously cold and wet - by no means a remote possibility - not only could we lose the momentum of public interest, but some of our credibility as well.

Rather than just blame the media for the swings in coverage and public opinion, scientists and all the climate "activists" should recognize that they may also be at fault here. There's so much effort to talk about climate change during the heat waves, that it can create a backlash during cold spells.

The message of climate change is one of a signal emerging from the noise. Perhaps we need to talk about the signal at a more constant rate over time, rather than let our communications efforts go up and down with the noise. 

1 comment:

Tonja said...

This is cool!