Agence France-Presse: The United States must do more to tackle climate change, the EU presidency said Wednesday, in a challenge to President Barack Obama ahead of a key international summit in Pittsburgh. “I hope to speed up the talks all over the climate issue,” Swedish Prime Minister Fredrik Reinfeldt said in online comments, the day before a EU summit Brussels. While acknowledging a promise by Japan’s incoming prime minister, Yukio Hatoyama, to target 25 percent cuts in greenhouse gas emissions, …