 As negotiators from more than 190 countries fought over details of a climate deal on Tuesday, US political celebrities stole the limelight with high profile calls for action. California Governor Arnold Schwarzenegger, former Vice President Al Gore, and New York City Mayor Michael Bloomberg drew crowds of journalists as UN officials inside the talks warned there was not enough progress towards an agreement. Television cameras, photographers and reporters chased them through the Copenhagen conference centre and journalists had to obtain tickets to attend speeches by Gore and Schwarzenegger. Normally, a press pass is the only ticket required. Gore, who shared the 2007 Nobel Peace Prize with the U.N. Intergovernmental Panel on Climate Change, tried using his influence to ease the political deadlock, calling on the U.S. Congress to finish work on a climate change bill by April 22, the 40th anniversary of Earth Day. And he urged the world to complete a global deal by July, assuming the Copenhagen summit ends this week with a political agreement by all the countries. Describing a "runaway melt" of the Earth's ice, rising tree mortality and prospects of severe water scarcities, Gore told a UN audience: "In the face of effects like these, clear evidence that only reckless fools would ignore, I feel a sense of frustration" at the lack of agreement so far. LOCAL LEADERSHIP Bloomberg and Schwarzenegger warned that with or without a global deal, states and cities would go forward with their own programs to reduce carbon dioxide pollution. "Certainly it would be terrific if the world's governments reached an agreement and put hard caps on greenhouse gases while generously helping poor nations" fight climate change, Schwarzenegger said. But he added: "The world's governments cannot do it alone," touting automobile fuel emissions standards and other carbon-reduction steps California has pioneered in the United States. Bloomberg, the self-made billionaire who last month won a third term in office, warned: "We can't sit around and wait for the federal governments to act." "If we, who represent half the people in the world living in cities ... (take action) we will get the national governments to follow. They are not going to be the leaders in this, we are." Despite that go-it-alone message, a meaningful reduction in the world's carbon pollution is not seen as achievable without an agreement by the more than 190 countries meeting in the Danish capital. And so when the biggest U.S. political star of the moment, President Barack Obama, arrives early on Friday, it may become clearer whether he and some 110 other leaders can shake hands on a political deal to control climate change.