BBC: The US faces "diplomatic consequences" if a new President decides to pull out of the Paris Climate Agreement.
American climate envoy Todd Stern said the reaction would be far greater than when the US left the Kyoto Protocol under President Bush.
Many countries are worried that a Republican victory in November's presidential election would see the US walk away from the landmark Paris deal.
But Mr Stern said he thinks this is unlikely given the global reaction.
The recent decision by the...