CNN: For the world's two largest economies -- and largest emitters of greenhouse gas -- to announce a sustained commitment to reducing carbon emissions by almost a third by the year 2030 is a watershed moment for climate politics on so many fronts.
Firstly, it raises the tempo worldwide regarding just how seriously we should be listening to the science and the Intergovernmental Panel on Climate Change (IPCC).
Secondly, it provides a new benchmark for international negotiations to break the lethargy...