Agence France-Presse: Some 125 world leaders are expected to commit to action on climate change at a UN summit Tuesday called to inject momentum in struggling efforts to tackle global warming. The gathering will be the largest ever of governments and heads of states on climate change and the first of its kind since the Copenhagen summit collapsed in disarray in 2009. US President Barack Obama is to outline his vision for limiting global warming, but key polluters China and India are sending lower-level representatives...