COP 21: David Cameron asks conference ‘what would we tell our grandchildren if we fail?’ – video

David Cameron makes a passionate appeal to other world leaders, calling on them to do what it takes to agree on a global climate change deal. Speaking to the Paris climate change conference on Monday, Cameron says the world needs a deal with a binding legal mechanism, with a five year review so we can 'see how we are doing.' He also calls for the transfer of technologies from the richest countries to the poorest countries