By Bjorn Lomborg

The continuous presentation of scary stories about global warming in the popular media makes us unnecessarily frightened. Even worse, it terrifies our kids.

Al Gore famously depicted how a sea-level rise of 20 feet (six meters) would almost completely flood Florida, New York, Holland, Bangladesh, and Shanghai, even though the United Nations estimates that sea levels will rise 20 times less than that, and do no such thing.

When confronted with these exaggerations, some of us say that they are for a good cause, and surely there is no harm done if the result is that we focus even more on tackling climate change. A similar argument was used when George W. Bush's administration overstated the terror threat from Saddam Hussein's Iraq.

But this argument is astonishingly wrong. Such exaggerations do plenty of harm. Worrying excessively about global warming means that we worry less about other things, where we could do so much more good.

We focus, for example, on global warming's impact on malaria ― which will be to put slightly more people at risk in 100 years ― instead of tackling the half-billion people suffering from malaria today with prevention and treatment policies that are much cheaper and dramatically more effective than carbon reduction would be.

Exaggeration also wears out the public's willingness to tackle global warming. If the planet is doomed, people wonder, why do anything? A record 54 percent of American voters now believe the news media make global warming appear worse than it really is.

A majority of people now believes ― incorrectly ― that global warming is not even caused by humans. In the United Kingdom, 40 percent believe that global warming is exaggerated and 60 percent doubt that it is manmade.

But the worst cost of exaggeration, I believe, is the unnecessary alarm that it causes ― particularly among children. Recently, I discussed climate change with a group of Danish teenagers. One of them worried that global warming would cause the planet to ``explode" ― and all the others had similar fears.

In the U.S., the ABC television network recently reported that psychologists are starting to see more neuroses in people anxious about climate change. An article in the Washington Post cited nine-year-old Alyssa, who cries about the possibility of mass animal extinctions from global warming.

In her words: ``I don't like global warming because it kills animals, and I like animals." From a child who is yet to lose all her baby teeth: ``I worry about [global warming] because I don't want to die."

The newspaper also reported that parents are searching for ``productive" outlets for their eight-year-olds' obsessions with dying polar bears. They might be better off educating them and letting them know that, contrary to common belief, the global polar bear population has doubled and perhaps even quadrupled over the past half-century, to about 22,000.

Despite diminishing ― and eventually disappearing ― summer Arctic ice, polar bears will not become extinct. After all, in the first part of the current interglacial period, glaciers were almost entirely absent in the northern hemisphere, and the Arctic was probably ice-free for 1,000 years, yet polar bears are still with us.

Another nine-year old showed the Washington Post his drawing of a global warming timeline. ``That's the Earth now," Alex says, pointing to a dark shape at the bottom. ``And then it's just starting to fade away."

Looking up to make sure his mother is following along, he taps the end of the drawing: ``In 20 years, there's no oxygen." Then, to dramatize the point, he collapses, ``dead," to the floor.

And these are not just two freak stories. In a new survey of 500 American pre-teens, it was found that one in three children aged 6-11 feared that the earth would not exist when they reach adulthood because of global warming and other environmental threats.

An unbelievable one-third of our children believe that they don't have a future because of scary global warming stories.

We see the same pattern in the United Kingdom, where a survey showed that half of young children aged 7-11 are anxious about the effects of global warming, often losing sleep because of their concern. This is grotesquely harmful.

And let us be honest. This scare was intended. Children believe that global warming will destroy the planet before they grow up because adults are telling them that.

When every prediction about global warming is scarier than the last one, and the scariest predictions ― often not backed up by peer-reviewed science ― get the most airtime, it is little wonder that children are worried.

Nowhere is this deliberate fear mongering more obvious than in Al Gore's Inconvenient Truth, a film that was marketed as ``by far the most terrifying film you will ever see."

Take a look at the trailer for this movie on YouTube. Notice the imagery of chilling, larger-than-life forces evaporating our future. The commentary tells us that this film has ``shocked audiences everywhere," and that ``nothing is scarier" than what Gore is about to tell us. Notice how the trailer even includes a nuclear explosion.

The current debate about global warming is clearly harmful. I believe that it is time we demanded that the media stop scaring us and our kids silly. We deserve a more reasoned, more constructive, and less frightening dialogue.

Bjorn Lomborg, director of the Copenhagen Consensus Center, is an adjunct professor at the Copenhagen Business School, and author of ``The Skeptical Environmentalist and Cool It: The Skeptical Environmentalist's Guide to Global Warming." For more stories, visit Project Syndicate (www.project-syndicate.org).