covered a lot of ground. he shook a few hands. conducted a few interviews. visited a few sites. even took a train ride. final stop, back to the united nations, where he used his address to press for a stronger commitment to end global warming, with a stark warning of the enduring consequences if countries didn't step up. we will see decertification, drought, crop failure and mass movements of humanity on a scale not seen before, not because of some unforeseen natural event or disaster, but because of us, because of what we are doing now. and our grandchildren will know that we are the culprits. the prime minister chose to focus solely on the subject of climate change. he used this global stage to make a strong speech ahead of the climate