Utility officials in northern Illinois said residents reduced the same amount of carbon dioxide as 104 acres of trees during the Earth Hour power turnoff.
Commonwealth Edison, the electrical utility company servicing Chicago and northern Illinois -- said that about 840,000 pounds of carbon dioxide were kept out of the atmosphere during the voluntary power shutoff Saturday night, the Chicago Tribune said.
The World Wildlife Fund promoted the event where cities and nations worldwide turned out the lights for an hour to raise awareness about global climate change and energy efficiency.
"I salute our customers, the City of Chicago and the other sponsors of Earth Hour Chicago," the head of ComEd, Frank Clark, said in a news release.
Copyright 2008 by United Press International
Explore further: Oil from Russian trawler wreck reaches Canaries' beaches