Editor's Note: This guest post is written by William S. Becker, Executive Director of the Presidential Climate Change Action Project.

The Copenhagen negotiations are taking place against a troubling backdrop of public opinion, according to several polls taken in recent months.

In the United States, the number of people who consider climate change a “very serious” problem has dropped from 44 percent of the population in April 2008 to 35 percent in October, according to a poll taken by the Pew Center on Global Climate Change. A Washington-Post/ABC poll in November generally confirms that trend, finding that the number of Americans who believe in climate change slipped from 80 to 72 percent in the past year.

In the European Union, 50 percent of residents consider climate change “the gravest problem in the world”, down from 62 percent in September 2008 according to a poll by the European Commission. In Australia, 48 percent of the population says it is willing to shoulder “serious” costs to solve the climate problem, down from 68 percent in 2006 and 60 percent last year, according to a Lowy Institute poll.

The good news is that in the United States, at least, public opinion about climate change has been “remarkably stable for the better part of two decades”, according to a new article by Ted Nordhaus and Michael Shellenberger.

Roughly two-thirds of Americans have consistently told pollsters that global warming is occurring. By about the same majority, most Americans agree that global warming is at least in part human-caused, with this majority roughly equally divided between those believing that warming is entirely caused by humans and those who believe it to be a combination of human and natural causes. And about the same two-thirds majority has consistently supported government action to reduce greenhouse gas emissions since 1989.

The bad news is that most Americans don’t feel strongly about the topic, Nordhaus and Shellenberger write. Over the past 20 years, only about 35-40 percent of the American public worries about climate change a “great deal”. Why?

The lesson of recent years would appear to be that apocalyptic threats—when their impacts are relatively far off in the future, difficult to imagine or visualize, and emanate from everyday activities, not an external and hostile source—are not easily acknowledged and are unlikely to become priority concerns for most people. In fact, the louder and more alarmed climate advocates become in these efforts, the more they polarize the issue, driving away a conservative or moderate for every liberal they recruit to the cause.

Nordhaus and Shellenberger call this “apocalypse fatigue."

The Economist blames the recession for some of the recent slippage in climate polls. But it also agrees with Nordhaus and Shellenberger that one cause is “talk of doom."

On one hand, some people are turned off by talk of doom….On the other hand, research suggests that people react well to a positive message, one that portrays a happy low-carbon future of electric cars, well-planned towns and affordable transport. They also like the idea that citizens as well as politicians have a choice between eco-disaster and a greener, better world.

Therein may lie the key to building broader and deeper public commitment to bold climate action: Helping people understand the dynamic, positive future ahead in a clean energy economy. The news media brings us the dire predictions of climate scientists, as it should. The entertainment media brings us technicolor surround-sound images of civilization’s collapse, most recently in the movie 2012, which predicts the world will end on Dec. 21 in that year.

The same artistry and state-of-the-art technologies could be used to show us what life would be like in a sustainable society – our homes, schools, transit systems, neighborhoods, energy systems, urban and rural areas. At the University of Colorado School of Public Affairs, I have been leading an effort to create those visions using video and computer animations.

 Positive visions of the future need not fall into the trap of “happy talk”, as Yale environmental dean Gus Speth puts it. They should acknowledge and show how communities will cope with the serious climate changes already underway. They should be culturally sensitive and place-based: a city in the United States need not and should not look like a city in India, for example.

We can use other new technologies to allow people to comment on future visions, to express what they like and don’t like, and to participate in design. That type of civic engagement builds the sense in the public that they own the vision, will work for it and defend it.

One thing is certain: We need to begin a constructive international conversation about building the future we want. We either will be tomorrow’s architects or its victims. There still is time to become the former. But as the doomsayers say, time is running out.