Pointing to the natural occurrence of carbon dioxide, which is exhaled by humans, conservatives in the media -- including Sean Hannity, Rush Limbaugh, Glenn Beck, and Jim Quinn -- have challenged, and even ridiculed, the idea that its presence can be harmful to the environment. For example, after claiming on the May 20 edition of his nationally syndicated radio show that carbon cap-and-trade proposals are based on “the phony science of global warming,” Sean Hannity stated, “You know what? The Earth -- we breathe carbon dioxide. You know, if you -- there's nothing wrong with the automobile.” Other examples include:

• On the May 20 broadcast of Clear Channel's The War Room with Quinn & Rose, co-host Jim Quinn stated, “Carbon is not pollution. I repeat, carbon is not pollution. We are made of carbon. Carbon is essential. Carbon dioxide is essential. As a matter of fact, we probably have too little carbon dioxide in the air right now. We could use more.”

• On the May 13 edition of his nationally syndicated radio show, while discussing a memo reportedly issued by the Small Business Administration's Office of Advocacy that argued against regulating greenhouse gases under the Clean Air Act, Limbaugh stated, “This is again not a surprise to me because we exhale C0₂. If it were a poison, if it were something -- we would -- wouldn't be part of the way we stay alive.”

• On the May 13 edition of his Fox News program, Beck stated, “Carbon dioxide is basically this” -- and exhaled. He further remarked: “Look how much pollution I just put out.”

• On the April 28 edition of his Fox News show, during an interview with Anadarko Petroleum CEO James Hackett, Beck stated, “I'm going to harm the planet. I'm going to give some CO₂ off,” and then exhaled. He added, “Dangerous. That should have been bottled and kept away from the planet because” -- and he exhaled again -- “that's a dangerous gas.” Seconds later, Beck exhaled into his cupped hands to demonstrate “sequestering” carbon dioxide, and then described cap-and-trade policies as being “only allowed to breathe, let's say, 50 times a day. If I breathe any more than 50 times a day, then I have to pay for all of the stuff that comes out of my mouth, right?”

• On the April 21 broadcast of his radio show, Beck asked, "[H]ow could carbon dioxide be a poison when it's naturally occurring and the trees use it to grow?" He added: “Stop. Just stop, will you? Stop with the lies.”

But scientists are not saying that carbon dioxide is inherently harmful, as Media Matters for America has documented. Rather, they point to the danger posed to the atmosphere by excessive discharges of C0₂, as the Natural Resources Defense Council has noted:

[A] pollutant is a substance that causes harm when present in excessive amounts. CO₂ has been in the atmosphere since life on earth began, and in the right amounts CO₂ is important for making the earth hospitable for continued life. But when too much CO₂ is put into the atmosphere, it becomes harmful. We have long recognized this fact for other pollutants. For example, phosphorus is a valuable fertilizer, but in excess, it can kill lakes and streams by clogging them with a blanket of algae.

Indeed, while C0₂ is a natural gas, the current levels in the atmosphere are the result of human activities. According to the Environmental Protection Agency, “Since the Industrial Revolution in the 1700's, human activities, such as the burning of oil, coal and gas, and deforestation, have increased CO₂ concentrations in the atmosphere. In 2005, global atmospheric concentrations of CO2 were 35% higher than they were before the Industrial Revolution.”

According the 2007 United Nations' Intergovernmental Panel on Climate Change's 2007 "Synthesis Report," “Global GHG [greenhouse gas] emissions due to human activities have grown since pre-industrial times, with an increase of 70% between 1970 and 2004.” It further explains, “Carbon dioxide (CO2) is the most important anthropogenic GHG. Its annual emissions have grown between 1970 and 2004 by about 80%, from 21 to 38 gigatonnes (Gt), and represented 77% of total anthropogenic GHG emissions in 2004.”

From the May 20 broadcast of Clear Channel's The War Room with Quinn & Rose:

QUINN: By the way, a note to Repower America, who keeps running these commercials about how cap and trade and green energy's going to be the solution to everything and the steelworkers are all going to be employed and all that stuff? Carbon is not pollution. I repeat, carbon is not pollution. We are made of carbon. Carbon is essential. Carbon dioxide is essential. As a matter of fact, we probably have too little carbon dioxide in the air right now. We could use more. Because the earth is cooling, and it's cooling rapidly.

From the April 28 edition of Fox News' Glenn Beck:

BECK: James, cap and trade: Not a tax?

HACKETT: Oh, it's definitely a tax, Glenn. And I think anybody who tells you otherwise is treating you to fiction. The key is --

BECK: Explain it to the American people in a way they can see how this scam -- I mean, this plan works.

HACKETT: I think you've got to start, actually, back with what carbon does to the world. And I think that all of us are familiar with burning wood, you know, centuries ago. We've advanced as a society where we're much more efficient in the burning of carbon fuels. It constitutes about 3 percent of all the greenhouse gas emissions, so you're talking about a very small portion of all of the greenhouse gases. The rest is actually water vapor.

Of that 3 percent, another portion of that is man-made emissions. There's a lot of other CO₂ emissions from other places. And it's a life-giving form, as many of us know, because plants use it. We breathe it about every three seconds. We exhale it.

BECK: Yeah, hang on just a second.

HACKETT: And to think that the EP--

BECK: Hang on. Let me just inter-- James, I'm sorry to interrupt. America, I'm going to harm the planet. I'm going to give some CO₂ off. Ready?

[exhales]

Dangerous. That should have been bottled and kept away from the planet because [exhales] that's a dangerous gas. OK. So, anyway, you were saying?

HACKETT: Well, and I think all of us can agree that man-made emissions can't possibly be good, but it means at what cost do we change that, that model that has taken us over a century to build? And our view is, we were, you know, original -- we were original climate reporters and founding reporters in The Climate Registry. We've got the largest CO₂ sequestration project in the world in Wyoming, that we're taking CO₂ that would otherwise be vented into the atmosphere. We're a founding member of the American Carbon Registry. We care deeply about --

BECK: OK, wait, wait, wait, wait, wait. So, that's -- sequestering it, that would be --

[Beck exhales into his cupped hands]

HACKETT: Right. Holding your breath. That's right.

BECK [whispering]: Put it in my pocket.

HACKETT: And so I think why you care about it -- you care about it in an intelligent, prudent way, and you don't treat it as if it's an EPA-regulated toxic gas, which is what they're suggesting. It's not a toxic gas by definition. And to suggest that the science on it is completely determined is also, I think, a big mistake.

BECK: OK, so now we've taken this --

HACKETT: It only took --

BECK: And, now, hang on just very quick. We take this invisible gas that [exhales] -- OK? Now, I'm only allowed to breathe, let's say, 50 times a day. If I breathe any more than 50 times a day, then I have to pay for all of the stuff that comes out of my mouth, right?

If I only breathe 30 times a day, well, then, I can sell those extra 20 breaths to somebody else that wants to breathe 20 times more than 50, correct?

From the May 13 edition of Fox News' Glenn Beck:

BECK: By the way, just so you know, because I know -- this show has won so many science awards. Sometimes, we get talking about highfalutin science things like this and people are like, “What are you talking about?” So, let me just break it down. Carbon dioxide is basically this:

[exhales]

Look how much pollution I just put out.

Hannah Kieschnick is an intern at Media Matters For America.