Warden declined to say how much the billboard campaign, which will run for a month in metro Atlanta, will cost and who is paying for it. In other cities, billboards have been paid for by individual donors. California-based Family Radio Worldwide, a Christian nonprofit radio network, sponsored the billboards in Nashville.
The campaign has raised some eyebrows locally, even before the first billboard is up.
The Rev. Kevin Myers, senior pastor of 12Stone Church in Lawrenceville, said the Bible says that Christ will return, but doesn't say when.
"I don't think it helps to define the date and put it out there. It conflicts with the very Scripture you're encouraging people to read."
David P. Gushee, a professor of Christian ethics and head of the Center for Theology and Public Life at Mercer University, agreed. "I'm glad they have it figured out," he said. "No one knows the day or the hour. Only the Father knows and I think that teaching has provided good guidance to Christians throughout the centuries. You never attempt to fix a date for Christ's return."
If May 21 passes with no return, he said, it could prove to be embarrassing for the campaign organizers and a disappointment for those who take such things seriously. "It's really a bad idea."
Smyrna resident Ed Buckner, a member of the board and former president of American Atheists, said the group is considering a reply.
"In all honesty, I think Christians, and not just atheists, ought to ridicule these billboards and protest against them," he said. "They're really putting Christianity on the spot."
According to WeCanKnow.com, following the rapture for believers on May 21, God will destroy the world on Oct. 21, 2011.
Recently, both believers and nonbelievers have been using outdoor advertising to get their point across.
American Atheists recently created a stir with a billboard about Christmas outside the Lincoln Tunnel in New Jersey, saying "You know it's a myth -- this season, celebrate reason." The billboard was countered by the Catholic League, which put up its own billboard, "You know it's real -- this season celebrate Jesus."