Reuters: Landmarks such as Sydney’s Opera House, Beijing’s Forbidden City and Taiwan’s Taipei 101 office tower temporarily went dark on Saturday as nations dimmed the lights for Earth Hour 2010 to call for action on climate change. The symbolic one-hour switch-off, first held in Sydney in 2007, has become an annual global event and organizers World Wide Fund for Nature said they expect this year’s to be the biggest so far. The remote Chatham Islands was the first of more than 100 …