BBC: The head of the UN body tasked with delivering a global climate treaty broke down in tears at a meeting in London as she spoke about the impact of global warming on coming generations.
Christiana Figueres told the BBC that the lack of an agreement was "condemning future generations before they are even born".
Ms Figueres said this was "completely unfair and immoral".
Despite the slow pace of negotiations, she said a deal can be done by 2015.
Costa Rica-born Christiana Figueres has been...