World Wildlife Fund president and CEO Carter Roberts was proud the Coliseum in Rome, the Golden Gate Bridge in San Francisco and some of Atlanta's tallest buildings were going dark during Earth Hour on Saturday.

But also on the list of accomplishments for Carter, a native of Atlanta, was that the Varsity on North Avenue and the Big Chicken in Marietta also signed on.

"This Earth Hour event has become a phenomenon," said Carter, who was in Atlanta to flip a giant mock light switch on top of the Wachovia Tower at Atlantic Station to start a wave of lights out in more than 50 office buildings and scores of other businesses and homes in the metro area.

Atlanta was one of four flagship cities in the United States to go dark in the hour between 8 and 9 p.m. By Saturday, Carter said, the number of cities participating worldwide in the rolling hour of lights out had grown to nearly 400.

It was to start in Christ Church, New Zealand, and end in San Francisco. Experts say the hour will temporarily cut electricity consumption about 5 percent.

"The energy savings is significant, but it's not enough to affect climate change," Roberts said. "It's symbolic [and a precursor] for people to make bigger commitments. This issue is not going away."

Saturday's Earth Hour was the second in two years. The first one — on March 31, 2007 — only involved one city, Sydney, Australia.

"People want to do something, and they aren't sure what," Roberts said. "It's providing an easy way for people to recognize the problem."

The organization's focus when it was founded in 1961 was wildlife conservation, but its energies expanded to wildlife habitats and eventually to the overall environment.

Roberts said his movement is getting help from unlikely sources — from major corporations to fishermen.

Consider water. Corporations need water to make their product; fishermen need healthy water sources to earn their livelihood. Yet, Roberts said, "it's going to become the scarcest commodity."

Sportsmen soon may see shifts in the wildlife they hunt because of changes in habitat. Rivers in the southeastern U.S. are on the World Wildlife Fund's list of 20 projects, Roberts said.

"Global warming could get rid of trout in the Southeast," Roberts said. "All these people are starting to see the things they care about disappear."