The debate over global warming has created predictable adversaries, pitting environmentalists against industry and coal-state Democrats against coastal liberals.
But it has also created tensions between two groups that might be expected to agree on the issue: climate scientists and meteorologists, especially those who serve as television weather forecasters.
Climatologists, who study weather patterns over time, almost universally endorse the view that the earth is warming and that humans have contributed to climate change. There is less of a consensus among meteorologists, who predict short-term weather patterns.
Joe Bastardi, for example, a senior forecaster and meteorologist with AccuWeather, maintains that it is more likely that the planet is cooling, and he distrusts the data put forward by climate scientists as evidence for rising global temperatures.
"There is a great deal of consternation among a lot of us over the readjustment of data that is going on and some of the portrayals that we are seeing," Bastardi said in a video segment posted recently on AccuWeather's Web site.
Such skepticism appears to be widespread among TV forecasters, about half of whom have a degree in meteorology. A study released on Monday by researchers at George Mason University and the University of Texas at Austin found that only about half of the 571 television weathercasters surveyed believed that global warming was occurring and fewer than a third believed that climate change was "caused mostly by human activities."
More than a quarter of the weathercasters in the survey agreed with the statement "Global warming is a scam," the researchers found.
The split between climate scientists and meteorologists is gaining attention in political and academic circles because polls show that public skepticism about global warming is increasing, and weather forecasters — especially those on television — dominate communications channels to the public. A study released earlier this year by researchers at Yale and George Mason, for example, found that 56 percent of Americans trusted weathercasters to tell them about global warming far more than they trusted other news media or public figures like former Vice President Al Gore or Sarah Palin, the former Alaska governor and vice presidential candidate.
The George Mason-Texas survey found that about half of the weathercasters said they had discussed global warming on their broadcasts during informal chats with anchors, and nearly 90 percent said they had talked about climate change at live appearances at Kiwanis Club-type events.
Several well-known forecasters — including John Coleman in San Diego and Anthony Watts, a retired Chico, Calif., weatherman who now has a popular blog — have been vociferous in their critiques of global warming.
The dissent has been heightened by recent challenges to climate science, including the discovery of a handful of errors in the landmark 2007 report on global warming by the United Nations' Intergovernmental Panel on Climate Change and the unauthorized release of hundreds of e-mail messages from a British climate research center last fall that skeptics say show that climate scientists had tried to suppress data.
"In a sense the question is who owns the atmosphere: the people who predict it every day or the people who predict it for the next 50 years?" said Bob Henson, a science writer for the University Corporation for Atmospheric Research, who trained as a meteorologist and has closely followed the divide between the two groups.
Henson added, "And the level of tension has really spiked in recent months."
The reasons behind the divergence in views are complex. The American Meteorological Society, which confers its coveted seal of approval on qualified weather forecasters, has affirmed the conclusion of the United Nations' climate panel that warming is occurring and that human activities are very likely the cause. In a statement sent to Congress in 2009, the meteorological society warned that the buildup of heat-trapping gases like carbon dioxide in the atmosphere would lead to "major negative consequences."
Yet, climate scientists use very different scientific methods from the meteorologists. Heidi Cullen, a climatologist who straddled the two worlds when she worked at the Weather Channel, noted that meteorologists used models that were intensely sensitive to small changes in the atmosphere but had little accuracy more than seven days out. As a result, Cullen said, meteorologists are often dubious about the predictions made by climate scientists, who use complex models to estimate the effects of climate trends decades in the future.
But the cynicism, said Cullen, who now works for Climate Central, a nonprofit group that works to bring the science of climate change to the public, is in her opinion unwarranted.
"They are not trying to predict the weather for 2050, just generally say that it will be hotter," Cullen said of climatologists. "And just like I can predict August will be warmer than January, I can predict that."
Three years ago, Cullen found herself in a heated dispute with meteorologists after she posted a note on the Weather Channel's Web site suggesting that meteorologists should perhaps not receive professional certification from the meteorological society if they "can't speak to the fundamental science of climate change."
Resentment may also play a role in the divide. Climatologists are almost always affiliated with universities or research institutions where a doctoral degree is required. Most meteorologists, however, can get jobs as weather forecasters with a college degree.
"There is a little bit of elitist-versus-populist tensions," Henson said. "There are meteorologists who feel, 'Just because I have a bachelor's degree doesn't mean I don't know what's going on.'"
Whatever the reasons, meteorologists are far more likely to question the underlying science of climate change. A study published in the January 2009 newsletter of the American Geophysical Union, the professional association of earth scientists, found that while nearly 90 percent of some 3,000 climatologists who responded agreed that there was evidence of human-driven climate change, 80 percent of all earth scientists and 64 percent of meteorologists agreed with the statement. Only economic geologists who specialized in industrial uses of materials like oil and coal were more skeptical.
Seeing danger in the divide between climate scientists and meteorologists, a variety of groups concerned with educating the public on climate change — including the National Environmental Education Foundation, a federally financed nonprofit, and Yale — are working to close the gap by using research and educational forums to bring the two groups together. In 2008, for example, Yale began holding regular seminars with well-known weathercasters who are unsure about the climate issue and scientists who are leading experts in the field. The Columbia Journalism Review explored the reasons for the split in an article this year.
Conversely, the Heartland Institute, a free-market research organization skeptical about the causes and severity of climate change, is also making special efforts to reach out. At its annual conference to be held in May in Chicago, the institute tried without success to put on a special conference just for meteorologists.
"What we've recognized is that the everyday person doesn't come across climatologists, but they do come across meteorologists," said Melanie Fitzpatrick, a climate scientist for the Union of Concerned Scientists. "Meteorologists do need to understand more about climate because the public confuses this so much. That is why you see efforts in this turning up."