PRAGUE, Sun Apr 5, (bdnews24.com/Reuters) - The United States is ready to take a leading role in tackling climate change, President Barack Obama said on Sunday, receiving a cautious welcome from European hosts at a summit in the Czech capital Prague. "Together, we must confront climate change by ending the world's dependence on fossil fuels, by tapping the power of new sources of energy like the wind and sun, and calling upon all nations to do their part," Obama said in a speech to the crowd outside the medieval Prague Castle. "I pledge to you that in this global effort, the United States is now ready to lead." Obama has taken a more assertive stance on global warming, which scientists say is caused by the release of gases such as carbon dioxide, than his predecessor George W. Bush. Last month, he invited 16 "major economies" including the European Union to take part in a forum on climate change to help ensure a UN pact on global warming is reached at a conference in Copenhagen in December. "The United States will be an active partner in the Copenhagen process and beyond," Obama told the 27 EU leaders at the EU-US summit. "We must not only reach an agreement among ourselves but also present a common approach that will bring other countries into the dialogue." Jose Manuel Barroso, the head of the EU's executive, the European Commission, said the United States and Europe had now come closer to agreeing on the subject. "We welcome the steps taken by the new American administration and the increasing convergence between the European and US position on that matter," he told reporters after the summit in Prague, but added there was further to go. The climate change talks in Copenhagen should lead to a new pact on fighting the global warming, replacing the UN's 1997 Kyoto Protocol.