WASHINGTON (Reuters) - You don't need a weatherman to know which way the wind blows.

But weather forecasters, many of whom see climate change as a natural, cyclical phenomenon, are split over whether they have a responsibility to educate their viewers on the link between human activity and the change in the Earth's climates.

Only 19 per cent of US meteorologists saw human influences as the sole driver of climate change in a 2011 survey. And some, like the Weather Channel's founder John Coleman are vocal in their opposition.

"It is the greatest scam in history," wrote Coleman, one of the first meteorologists to publicly express doubts about climate change, on his blog in 2007. "I am amazed, appalled and highly offended by it. Global Warming; it is a SCAM."

The climate change controversy has split the American Meteorological Society, whose members are Americans' prime source of news about weather and climate

In its last official view issued in 2007, the AMS acknowledged that global warming is occurring and that human activities exacerbate it, especially the burning of fossil fuels and the release of the climate-warming gas, carbon dioxide.

Research since 2007 has only solidified climate science findings, said AMS Executive Director Keith Seitter. AMS members who disagree, he said, are in a minority, though an often outspoken one.

"There are some extremely vocal people who are arguing on that issue, but I think the science has continued to become more clear, not less so," Seitter said by telephone from Boston.

The controversy has held up the society's updated view on climate change but Seitter said expects the new AMS statement to hew closely to its position in 2007 and include updated scientific findings.

An online grassroots campaign called "Forecast the Facts" said the society needs to go beyond a strong statement on climate change and require that its members "report the current scientific consensus on climate change."

"As it stands right now, it is considered within the realm of acceptable discourse for media outlets, corporations and politicians to deny climate change and to stand in the way of much needed action," Daniel Souweine, who heads the campaign, said in an email.

Forecast the Facts is supported by the non-profit environmental groups League of Conservation Voters and 350.org, and has gotten 14,000 signatures for its petition to the AMS, Souweine said.

They will be hard-pressed to convince forecasters like Bob Breck, a weatherman at Fox Channel 8 in New Orleans who is vocal in his scepticism over climate change.

"AMS has long been dominated by people in academia, which is ok, they're the PhDs ... except those of us who I consider operational meteorologists, we were basically ignored," Breck said by telephone. "I believe in global warming cycles and we have been in a warming cycle. What I don't believe is that the driver of this current warming cycle is carbon dioxide."

Most weathermen and women have degrees in meteorology – the study of how Earth's atmosphere behaves in the short term – but few have studied climate science, which examines the wider system where weather occurs.

THE DIVIDE

But meteorologists advise Americans every day, and that makes them powerful shapers of public opinion. Most don't mention global warming in their weathercasts, but many also blog, and that is often where the scepticism surfaces.

Most US meteorologists – 82 per cent in a 2011 survey – are convinced that climate is changing, but many say it's changing because of natural causes, or human and natural causes combined.

That contrasts with about 95 per cent of climate scientists who are convinced that climate change is occurring and that human activities, particularly the burning of fossil fuels, are a key driver of it. This tallies with the UN Intergovernmental Panel on Climate Change, which reported with 90 per cent certainty in 2007 on the causes and effects of climate change.

To Edward Maibach, director of the Center for Climate Change Communication at George Mason University, that split shows that efforts like Forecast the Facts are misguided.

"It presumes that AMS is part of the problem, and I actually think the AMS is doing really, really solid work to help their weathercaster members expand the way they currently define their day job to include climate education as part of their role," Maibach said.

Maibach, who tracks meteorologists' attitudes on climate change, said sceptics in the group believe their concerns are being ignored.

"They feel their views and their concerns about the science are not being taken seriously," Maibach said. "It's pretty easy to understand how one gets to a place of anger when they feel dismissed and disrespected."

(Reporting By Deborah Zabarenko, Environmental Correspondent; Editing by Michele Gershberg and Jackie Frank)