How does more snow equal global warming?

BOSTON — You may not have heard of “Climategate” or the “hockey stick controversy.” But that doesn’t mean you haven’t found yourself thinking like a climate change skeptic lately.

Perhaps you’re reading from Washington, D.C., marooned at home by a second consecutive blizzard. Or maybe you’re in Scotland, which just recorded its coldest winter in more than a century. Maybe you’re just a little too cold to feel like the world is getting warmer.

"There’s nothing like a very cold winter to convince another percentage of the American public that global warming is not happening,” said American University professor Matthew Nisbet at Harvard University this week.

Indeed, the Republican Party in Virginia seized on the mid-Atlantic “snowpocalypse” to produce an advertisement criticizing Democrats in Congress who support "cap-and-trade" policies that provide economic incentives to reduce pollution emissions.

The ad advises viewers to call their representative and “tell them how much global warming you get this weekend. Maybe they’ll come help you shovel.”

(The ad has since been pulled from YouTube, possibly because of the highly negative coverage it generated.)

But weather hasn’t been the only thing raining on the climate change parade. A long list of setbacks have fanned the flames of climate gloom since the breakout 2006 Al Gore documentary “An Inconvenient Truth” energized public attention toward the issue.

As China rose earlier than expected as the world’s top CO2 emitter, followed by a worldwide economic downturn, fewer people list climate change as a top priority.

Throw in the failure of the Copenhagen talks to produce a substantial climate agreement. The percentage of people worldwide who doubt the research backing climate change continues to grow.

Why such a change in the climate of public opinion?

American public support for climate-change action has been damaged by reports that later proved flimsy. Two apocalyptic predictions in the second report by the Intergovernmental Panel on Climate Change (IPCC) — that Himalayan glaciers would disappear by 2035 and that warming in the Amazon would cause mass murder of vegetation— were both based on single, anecdotal magazine articles.

Data from Chinese temperature collection centers could not be verified. Hundreds of emails from the British Climatic Research Unit (CRU) were hacked and disseminated, revealing damning correspondences that appeared to show scientists were conspiring to suppress contradictory data. The fallout from this email scandal was so great that the man at the center of it — former director of the CRU Phil Jones — contemplated suicide.

Doubt also has been cast on the famous “hockey stick” graph that shows a steep incline in average temperatures.

"People are very suspicious of estimates of numbers of deaths.  … [They] tend to discount that," said Professor Nisbet, who studies climate change communication in the media. "Instead, if you talk about something more tangible and perceived as less threatening — asthma, allergies, increased vulnerability of people in cities to heat waves — those things are easier for the public to sort though and connect to their daily lives.”

While the third IPCC report presented a collection of data on temperature and greenhouse gas increases over time, which in many ways transformed climate change into a widely accepted theory, the fourth attempted to contextualize the impacts those increases may have on people around the world. Its effect may have been to push more people away from the issue.

Overall, a trend emerges. An eagerness to encourage the public to understand the threat of climate change seems to have influenced some to emphasize the apocalyptic while diminishing the nuanced. The result: more and more conservatives discount the science behind climate change. Nisbet said that when presented with such “threat appeals” without also presenting viable recourses, most people “either ignore [them] or have a sense of fatalism.”

Indeed, “An Inconvenient Truth” marketed itself as “the most terrifying film you will ever see,” and used a hurricane on its poster — just one year after the disaster of Hurricane Katrina.