Agence France-Presse: German Chancellor Angela Merkel on Tuesday urged the US Congress to take action on climate change, likening the struggle against global warming to the Berlin Wall. In a rare address to a joint session of Congress marking the fall of the Berlin Wall 20 years ago, Merkel said next month’s high-stakes climate summit in Copenhagen hinged on strong US and European commitments. “I’m convinced, just as we found the strength in the 20th century to bring about the fall of a wall made of …