Reuters: Negotiators facing a Friday deadline hammered out an initial draft U.N. climate pact overnight that calls for a two degree Celsius cap on global temperatures and billions in aid for poor nations, sources said. U.S. President Barack Obama will join more than 120 other world leaders on the final day of the climate talks, designed to strike a deal to boost international efforts to curb greenhouse gas emissions widely blamed for heating up the planet. The draft still under …