A three-day summit in Denmark has heard time is running out to reach a deal on how to fight global warming.Former US Vice President Al Gore told the World Business Summit on Climate Change in Copenhagen the clock was ticking. In his keynote speech he said greater political will was needed. He said: “At this moment we are facing three inter related crises in the world, the climate crisis, the economic crisis and the energy security concerns that have been factors in wars and political and military tensions. There is a common thread linking all of these threes crises, it is our absurd overdependence on carbon based fuels.” The United Nations hopes to get a new global warming treaty approved to replace the Kyoto Protocol on cutting carbon emissions that expires in 2012. Meanwhile the European Union has already said it will slash emissions by 20 percent by 2020.