Agence France-Presse: Leaders of the world’s established and emerging economic powerhouses will be under pressure at this week’s G8 summit to give a badly-needed jolt to the quest for a new global climate pact. Negotiators struggling to seal an agreement in Denmark by year’s end say the three-day summit, opening on Wednesday in L’Aquila, Italy, is a golden opportunity to haul the process out of a rut. “It’s time to make a difference,” Yvo de Boer, executive secretary of the UN’s Framework Convention …