The GlobalFrackdown website and campaign was developed by Food & Water Watch, a Washington, D.C. nonprofit that was once part of Ralph Nader's Public Citizen group. The campaign claims that fracking "has already damaged communities and ruined lives. It pollutes water and makes people sick."
Scientists disagree on the risks of fracking, a process that injects large volumes of water, sand, and chemicals underground to break rock apart and free the gas. The U.S. Environmental Protection Agency and many state regulators, however, say that fracking can be done safely. The American Lung Association says natural gas has helped reduce air pollution as many dirtier coal-fired power plants shift to natural gas.
The immense volumes of natural gas found in formations of shale rock around the country has spurred a boom in natural gas production that has been credited with creating jobs and lowering prices for industry and consumers.
The Frackdown campaign doesn't mention the differing opinions over risks or any benefits of fracking.
Mark Schlosberg, the national organizing director for Food & Water Watch, said supporters of the campaign are concerned about access to safe drinking water now and in the future. And some people simply don't want fracking in their communities, he said.
"The message is, we need to ban fracking," he said. "We think fracking is just another dirty fossil fuel."
Shale is a rock formation thousands of feet underground. Among its largest U.S. deposits are the Marcellus Shale, under parts of Pennsylvania, New York, Ohio and West Virginia, and the Barnett Shale is in north Texas. Geologists knew shale contained gas, but for more than 100 years the industry focused on shallower reserves. Fracking — also called hydraulic fracturing — allows drillers to profitably extract the deep shale gas.
Contaminated wastewater from the process can leak from faulty well casings into aquifers, but it's often difficult to prove a connection. Some studies also have shown air quality problems around gas wells, while others have indicated no problems.
Regulators contend that overall, water and air pollution problems are rare, but environmental groups and some scientists say there hasn't been enough research on those issues. But some industry leaders also say more needs to be done to address concerns.
At a gas drilling conference this week in Philadelphia, XTO Energy President Jack Williams acknowledged that some Americans still are very concerned about the impact of shale drilling on their communities and the environment.
"Our industry must take steps to strengthen public confidence," he said.
At the same conference Pennsylvania Gov. Tom Corbett attacked anti-drilling activists as the "unreasoning opposition" who accept that the United States can land a space vehicle on Mars but don't believe energy companies can safely harvest gas a mile under the earth's surface.
Fracking also is being debated around the world. Earlier this month, South Africa decided to allow fracking in the semi-desert Karoo region. Cabinet ministers agreed to lift a year-old moratorium, based on a report by a technical team. Shale gas is being touted as a viable alternative to expensive electricity in a country often short of power, and a boost for the economically depressed Karoo.
There also are spirited debates over fracking in France, Poland, and other European countries.
James Saiers, a professor of hydrology at the Yale School of Forestry & Environmental Studies, said some people on both sides of the fracking debate are locked into assumptions.
"The critics on either side, they tend to believe the worst. And that's unfortunate, because there are sincere people on either side," Saiers said. "It will remain a polarized issue. Even data or evidence is unlikely to change those assumptions."
"My view is we have to promote renewables. But right now we're locked in to fossil fuels for a while longer. And trading natural gas for coal is a benefit," Saiers said.
One woman who plans to attend a Frackdown event in North Carolina said water use is her key concern.
"This is my own tipping point: the amount of water that it takes to pull this resource out of the earth is unacceptable," said Debra Demske, of Winston-Salem. North Carolina currently has no shale drilling, and only minor deposits.