Reuters: The United States and other rich nations must do more to help clinch a landmark deal on climate change this year, a top U.N. official said at a meeting of global environment ministers. The three-day meeting of the Group of Eight industrial countries and major developing economies, which opened in Sicily on Wednesday, has been hailed as a stepping stone to a U.N. deal on climate change, due to be signed in December in Copenhagen. All eyes were on the U.S. delegation since …