On the April 23 broadcast of 630 KHOW-AM's The Caplis & Silverman Show, KWGN CW2 meteorologist Rob “Sunny” Roseman made numerous false claims to support his contention that “man-made” global warming is “not settled science.” In addition to ignoring the consensus view that human activity is largely responsible for global warming, Roseman -- without substantiation and counter to evidence presented in numerous peer-reviewed studies -- falsely claimed that “500 years ago, the Earth was about 5 degrees warmer than it is” today. Co-host Dan Caplis responded to Roseman's falsehoods by saying he made some “great points.”

Roseman told Caplis that he has a master's degree in climatology, but he did not specify the institution that awarded it and his biography on the KWGN website does not provide that information. He responded to Caplis' question, “Sunny, what do you think of ... the underlying premise of man-made, man-corrected global warming?” by saying, “I don't think it's man-made.” Roseman added, “For some reason we as humans have a tendency to want to believe things that are popular in the media rather than just, say, listen to all of the scientists. Number one, it is not settled science -- I will tell you that; absolutely not settled science. I could put 500 climate people into a room and probably 250 of them are going to agree and 250 will disagree with it.”

Roseman's remarks about a purported lack of scientific consensus on why the Earth's temperature is rising echoed those of some conservative media figures who continue to dispute that human activity is responsible for increasing global temperatures, as Colorado Media Matters has noted. Furthermore, as Media Matters for America has documented (here, here, and here), scientific organizations such as the National Academy of Sciences (NAS), the Intergovernmental Panel on Climate Change (IPCC), and the Union of Concerned Scientists share the consensus view that human activity is largely responsible for observed climate change forcing. As an IPCC report released in February found:

Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic [human-produced] greenhouse gas concentrations. This is an advance since the TAR's [Third Assessment Report] conclusion that “most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations”. Discernible human influences now extend to other aspects of climate, including ocean warming, continental-average temperatures, temperature extremes and wind patterns. [Emphasis in original. The report defines “very likely” as a greater than 90 percent probability of occurrence.]

In May 2006, at the time of the theatrical release of former Vice President Al Gore's global warming documentary, An Inconvenient Truth, The New York Times published an article by Andrew C. Revkin reporting that mainstream scientists -- while taking issue with some details in the film -- embraced its premise and subscribed to Gore's “main point”:

In interviews and e-mail exchanges, many climate specialists who have seen the film quibbled about details but tended to agree with Eric Steig, a University of Washington geochemist who posted his reactions at the Web log realclimate.org after a recent Seattle screening: ''The small errors don't detract from Gore's main point, which is that we in the United States have the technological and institutional ability to have a significant impact on the future trajectory of climate change.''

A June 2006 Associated Press article reported a similar consensus among climate scientists, who said the film “mostly got the science right.”

Later in the interview, Roseman claimed that “500 years ago, the Earth was about 5 degrees warmer than it is now -- especially in North America and Northern Europe” and that “we have proof that when it was 5 degrees warmer, none of this bad stuff happened.” However, scientific research does not support Roseman's contention.

In response to a congressional request, the National Research Council (NRC) assembled a committee of climate professionals to “assess the state of scientific efforts to reconstruct surface temperature records for the Earth over approximately the last 2,000 years” and to produce a report presenting the committee's findings. A June 22, 2006, press release accompanying the report noted:

There is sufficient evidence from tree rings, boreholes, retreating glaciers, and other “proxies” of past surface temperatures to say with a high level of confidence that the last few decades of the 20th century were warmer than any comparable period in the last 400 years, according to a new report from the National Research Council.

And while the committee noted with respect to multiple studies that "[l]ess confidence can be placed in proxy-based reconstructions of surface temperatures for A.D. 900 to 1600," it nevertheless emphasized -- contrary to Roseman's claim -- that “evidence does indicate that many locations were warmer during the past 25 years than during any other 25-year period since 900.” As a summary accompanying the report further stated:

Evidence for regional warmth during medieval times can be found in a diverse but more limited set of records including ice cores, tree rings, marine sediments, and historical sources from Europe and Asia, but the exact timing and duration of warm periods may have varied from region to region, and the magnitude and geographic extent of the warmth are uncertain.

As the report itself notes, “Within Europe, only two continuous records currently extend back before 1500 ... both of which have been incorporated into synthetic large-scale temperature reconstructions.” The report states that these studies “mark the 20th century as exceptionally warm.” As MSNBC reported, with regard to recent warming as trends measured against a broad historical scale, the report concludes:

"[The] numerous indications that recent warmth is unprecedented for at least the last 400 years and potentially the last several millennia, in combination with estimates of external climate forcing variations over the same period, support the conclusion that human activities are responsible for much of the recent warming."

Moreover, as MSNBC observed, the NRC's report was commissioned by then-chairman of the House Science Committee, Rep. Sherwood Boehlert (R-NY), and was to “focus[] on research data criticized by warming skeptics ... published in 2001 by the Intergovernmental Panel on Climate Change,” which concluded that “the Northern Hemisphere was the warmest it has been in 1,000 years.” Yet rather than validating the skeptics' criticisms, the commission's review of the existing science further refuted the notion that present warming trends are not unprecedented in the historical record. As MSNBC reported, “John Wallace, an atmospheric sciences professor at the University of Washington and a panel member” confirmed that "[t]he conclusions from the [IPCC] research 'are very close to being right' and are supported by even more recent data."

As indicated by the plotting of the data from the seven studies it scrutinized the NRC found that, in relative terms, estimated temperatures for the year 1507 are well below observed global temperatures today. And as evidenced by the grey shading -- the darker shading indicating a lower degree of confidence in the given results -- the estimates from 500 years ago are not only consistent, but also carry a significant degree of scientific certainty.

From the April 23 broadcast of 630 KHOW-AM's The Caplis & Silverman Show:

CAPLIS: Now, Sunny, what do you think of this -- the, the underlying premise of man-made, man-corrected global warming?

ROSEMAN: I have a couple of thoughts. The biggest one is -- and by the way, I studied climatology; that's what I got a master's degree in. So I have studied this.

[...]

CAPLIS: So now for, for me -- you've got a master's in this stuff. Bottom line: Is it man-made, and if it is, can man correct it?

ROSEMAN: I don't think it's man-made. I could give you, and will give you, just a couple of examples of -- by way of questions -- that will make people question why they think it's man-made. For some reason we as humans have a tendency to want to believe things that are popular in the media rather than just, say, listen to all of the scientists. Number one, it is not settled science -- I will tell you that; absolutely not settled science. I could put 500 climate people into a room and probably 250 of them are going to agree and 250 will disagree with it. I've got a couple real simple questions to ask. As we all know, at one point -- or at several points over the last several thousand years --

CRAIG SILVERMAN [co-host]: Hey, Sunny, this is not TV, so you don't need to be simple.

ROSEMAN: [laughing] Yeah, but I'm a simple kind of guy, though, you know? That's the problem. Seriously though, Colorado was covered by thousands of feet of ice at some point. How did that melt unless there were some little guys driving around in cars that we didn't know about?

SILVERMAN: I think it was a lot of pee -- a lot of little boys peeing outside.

ROSEMAN: Maybe, and only using one thing of, of toilet paper. Maybe that was it.

SILVERMAN: That, that's -- that's clearly how it happened.

ROSEMAN: Oh, it had to have been; that's the only thing it could have been. But how about the other question: Greenland was named Greenland because guess what, it was green at one time.

CAPLIS: Right, right.

ROSEMAN: Before it became so ice encrusted. And now it's going back to that. The reality is, if you look back on the cycle, it is exactly that. We have --

SILVERMAN: But what about the ozone layer? You know, I don't know anything about science, but the, the people who are smart about this say that greenhouse gases are affecting the ozone layer. It, it does seem to make sense to me -- and I'm not a scientist, I didn't go to a correspondence school in climatology or anything like that. But as Bill O'Reilly -- who is just like me, not a scientist -- said, there's a lot of guck in the air. And isn't it natural to think that's not good for us?

ROSEMAN: OK, now I will agree with you a hundred percent -- we should not be using fuel to power our economy; we should be finding other things. But is that the sole cause of why it's warming now? I don't believe so. As far as ozone, by the way --

SILVERMAN: It's that and the toilet paper.

ROSEMAN: Well that and the toilet paper. We could, we could all go back to rocks. What do you think?

SILVERMAN: That doesn't sound too comfortable.

CAPLIS: I don't think so, Sunny.

ROSEMAN: Leaves and stuff like that. But, but seriously, 500 years ago, the Earth was about 5 degrees warmer than it is now -- especially in North America and Northern Europe. Guess what? Some of the best climate, the best crop-growing weather and everything else, and the seas weren't 3 feet higher than they are today.

CAPLIS: Mm-hmm.

ROSEMAN: So why all of a sudden because some computer model says it --

CAPLIS: Right.

ROSEMAN: -- we believe that, well because it's going to warm 1 degree, it -- when, when we have proof that when it was 5 degrees warmer, none of this bad stuff happened.

CAPLIS: Sunny, I think --

ROSEMAN: Why do we have that belief? I don't, I don't get that.

CAPLIS: I, I think those are all great points. And that's why I think at this point, folks need to have a chance to really think about this, to hear the competing scientists, apply their own common sense. You know, weigh in the cost in, in terms of real life: jobs, which means people lose houses, which means kids can't go to their schools. You know, the, the real-world costs of doing what people like Al Gore suggest we need to be doing and then, you know, let's come to some kind of conclusion. But I'm with you, Sunny; I don't think the debate's over. But thank you for your time today.

ROSEMAN: Sure -- thanks, guys. Appreciate you letting me yap a little.