aboard papal plane pope francis saturday urge world leaders turn back brink possible human annihilation suggest irrational attitude towards nuclear weapons pope make comment reporters aboard plane take back rome trip myanmar bangladesh dominate crisis rohingya refugees affect countries speech last month pope suggest ready officially harden decades-old church teach possess nuclear weapons deterrence morally acceptable long ultimate goal elimination speech nov. 10 francis say even mere possession nuclear weapons condemn appear little intention world leaders reduce number aboard plane ask prompt consider change official church position specifically felt war word u.s. president donald trump north korean leader kim jong un change irrationality attitude toward nuclear weapons francis say today limit say debate opinion conviction reach limit moral licitness use nuclear weapons say today sophisticate nuclear arsenal risk destruction humanity least great part humanity say pope past suggest third nation try negotiate deal unite state north korea urge side cool rhetoric stop trade insult limit limit ask question ... today licit keep nuclear arsenals today order save creation save humanity necessary turn back south korea say friday north korea late missile test put washington within range pyongyang still need prove master critical missile technology re-entry terminal stage guidance warhead activation test prompt warn unite state north korea leadership would utterly destroy war break statement draw sharp criticism russia pope decry 'irrational attitude towards nuclear weapons