PRAGUE (AFP) – President Barack Obama said Sunday the United States was ready to take the lead in tackling climate change, as EU leaders pushed him to follow their ambitious targets to combat global warming. "To protect our planet, now is the time to change the way that we use energy," Obama told a crowd gathered at Prague Castle for his only public speech during his maiden tour of Europe. "Together we must confront climate change by ending the world's dependency on fossil fuels by tapping the power from the sources of energy like the wind and the sun and...