Jo Dee Messina will play a free concert in downtown Nashville in honor of Earth Hour on Saturday (March 28). At 8:30 p.m., more than 200 Nashville businesses (including the honky-tonks on Lower Broadway) will go dark for one hour. Sponsored by World Wildlife Fund, the event is part of the world's largest demonstration of public concern for climate change. Messina's Web site will also be dark for 24 hours, with the exception of a brief message about Earth Hour and the streaming of her new single, "Shine." "I've been working hard to tell my fans and fellow Nashvillians about Earth Hour, so I hope the message has been getting through," Messina said. "Climate change is one of the most urgent issues facing the world today. And I'm proud to join everyone in Nashville, and millions around the world, to call on our leaders to take action."