BBC: Climate change is high on the agenda at the G8 summit in L’Aquila. Leaders of the major industrial countries are discussing targets for reducing global warming with counterparts from developing countries. Here are the promises that countries and supra-national bodies have already made. G8 The G8 leaders said on Wednesday that rich nations should cut emissions by 80% by 2050, while the world overall should reduce them 50% by 2050. They said they had agreed to try to limit …