Via hologram, Al Gore kicked off the event to some 47,000 in Sydney, with Crowded House and Earthmother among the performers.
The event itself has enjoyed a wave of publicity in recent days, focusing on criticism that the event has an ambiguous goal and the troubles that past marathon concerts have had in cutting through government bureaucracy. Instead of money raised, success is measured in whether people actually change their consumption habits and take concrete action.
There also have been various controversies in other countries. There were concerns about safety in Rio and in Germany, Greenpeace panned the concert because DaimlerChrysler was chosen as one of the sponsors.
With such ambitions, such controversies were bound to pop up.
But the backers of the concert did manage to cut through red tape in Washington, where they will stage events today at the National Museum of the American Indian. Trisha Yearwood will perform, among other artists. Organizers were denied access to the National Mall and stymied in their efforts to stage it on the steps of the Capitol.